Building a Solar Future: Repowering America's Homes, Businesses and Industry with Solar Energy

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Building a Solar Future Repowering America’s Homes, Businesses and Industry with Solar Energy Building a Solar Future Repowering America’s Homes, Businesses and Industry with Solar Energy

Environment America Research & Policy Center Tony Dutzik and Rob Kerth, Frontier Group Rob Sargent, Environment America Research & Policy Center Bernadette Del Chiaro, Environment California Research & Policy Center

March 2010 Acknowledgments

Environment America Research & Policy Center thanks Jigar Shah, CEO of the Carbon War Room; Carrie Hitt, president of the Solar Alliance; Justin Baca, manager of market research and analysis for the Solar Energy Industries Association; Adam Browning, executive director of Vote Solar; Larry Chretien, executive director of the Energy Consumers Alliance of New England; Wilson Rickerson, executive vice president of Meister Consul- tants Group; DeWitt Jones, president of DCC Solar Energy Advantage; and Bill Powers of Powers Engineering for their thoughtful review and insightful suggestions. Thanks also to Elizabeth Ridlington, Susan Rakov and Travis Madsen of Frontier Group for their editorial support.

Environment America Research & Policy Center thanks the John Merck Fund, the En- ergy Foundation, the Richard and Rhoda Goldman Fund, the Arntz Family Foundation, the Meadows Foundation, the Cynthia and George Mitchell Foundation, the Park Foun- dation, Fred Stanback, and the Kresge Foundation for making this report possible.

The authors bear responsibility for any factual errors. The recommendations are those of Environment America Research & Policy Center. The views expressed in this report are those of the authors and do not necessarily reflect the views of our funders or those who provided review.

Environment America Research & Policy Center is a 501(c)(3) organization. We are dedicated to protecting America’s air, water and open spaces. We investigate problems, craft solutions, educate the public and decision makers, and help Americans make their voices heard in local, state and national debates over the quality of our environment and our lives. For more information about Environment America Research & Policy Center or for additional copies of this report, please visit www.environmentamerica.org.

Frontier Group conducts independent research and policy analysis to support a cleaner, healthier and more democratic society. Our mission is to inject accurate information and compelling ideas into public policy debates at the local, state and federal levels. For more information about Frontier Group, please visit www.frontiergroup.org.

Cover photos: Top row (l to r): VELUX/ESTIF; Kevin Dooley, reprinted under Creative Commons license; Alex Snyder, Wayne National Forest; Gregory Kolb, Sandia National Laboratory; Sacramento Municipal Util- ity District; Solar panels: istockphoto.com, Daniel Schoenen Fotografie Layout: Harriet Eckstein Graphic Design Table of Contents

Executive Summary 1 Introduction 6 Why Solar? Why Now? 8 Building a Solar Future for America: The Tools 11 Photovoltaic Power 11 Concentrating Solar Power 12 Solar Water Heating 13 Passive Solar Lighting and Heating 14 Active Solar Heating and Cooling 15 A Solar Future for America 17 Solar Homes 17 Solar Businesses 20 Solar Factories 21 Solar on Farms 24 Solar in Transportation 26 Solar in Communities 28 Solar Grid 32 Mapping Out a Solar Vision 36 America’s Solar Potential 36 A Near-Term Goal 38 Achieving a Solar America 41 Understanding the Barriers to a Solar America 41 Policies to Build a Solar America 44 Notes 52

Executive Summary

merica has virtually limitless po- and light trucks, or nearly half as much as tential to tap the energy of the sun. we currently obtain from burning coal. ASolar energy is clean, safe, proven A comprehensive suite of public policy and available everywhere, and the price of strategies can remove many of the com- many solar energy technologies is declin- mon barriers to solar energy development ing rapidly. By adopting solar energy on and help to make this vision a reality. a broad scale, the nation can address our biggest energy challenges—our depen- There are many ways to take advan- dence on fossil fuels and the need to ad- tage of the sun’s energy. Solar energy dress global warming—while also boost- can be converted to electricity, or used ing our economy. for lighting, heating and cooling. It can America has the potential to obtain a replace the fossil fuels we burn at electric large and increasing share of our energy power plants, in factories, in our homes, from the sun. In the near term, America and even in our cars. Solar energy tech- should set the ambitious goal of ob- nologies include: taining 10 percent or more of our total energy consumption* from the sun • Photovoltaics (PV) – Photovoltaics by 2030, using a wide variety of tech- directly convert solar radiation into nologies and tools. Achieving that target electricity. PV can take the form would result in the sun providing us with of panels or be incorporated into more energy than we currently produce building materials. PV is scalable, at nuclear power plants, more than half as generates electricity anywhere much as we currently consume in our cars the sun shines, including in cold climates, has no essential moving parts, uses virtually no water, and is one of the few power generation * Note: This goal refers to total energy consumption from all sources in the United States, not just electric- technologies well suited for use in ity consumption. urban areas.

Executive Summary 1 • Concentrating solar power (CSP) Solar energy can help power virtual- – CSP plants use mirrors to focus ly every aspect of America’s economy. the sun’s energy to harness heat that can be used directly or to generate Solar Homes electricity. Because heat is cheaper and easier to store than electricity, • New homes can be built to maximize CSP plants with thermal storage use of the sun’s energy through can be designed to provide energy passive solar design and the use of from the sun even at night. CSP solar PV panels and water heating plants have been reliably generating systems. Solar energy can be paired power in desert areas of the West for with advanced energy efficiency decades and are now experiencing techniques to create zero net energy a resurgence due in part to falling homes, which produce as much costs and increasing demand for energy as they consume. Zero net utility-scale renewable electricity. energy homes have already been built in parts of the country, are possible in • Solar water heaters – Rooftop- all climates, and often save money for mounted collectors capture solar consumers over time. energy as heat and produce hot water. Solar heat collectors can be • Many existing homes can also extremely efficient; low-temperature incorporate solar technologies. heaters can capture up to 87 percent Photovoltaic panels can be installed of the solar energy that reaches on the roofs of 35-40 percent of them. Solar water heaters can also homes nationwide, and solar heat be adapted for uses ranging from collectors on 50 percent of residential residential water heating to large- roofs. scale industrial use.

• Solar space heating and cooling – Collectors similar to those used Solar Businesses for hot water can also be used to heat air in place of furnaces • Commercial buildings—such as or boilers. These systems can big-box stores, strip malls and contribute 50 percent or more of the office complexes—also have many energy needed to heat a building. opportunities to take advantage of Solar energy can even be used to solar energy. About 60 to 65 percent cool buildings through the use of of commercial roof space nationwide absorption chillers. is suitable for photovoltaics. Large- scale commercial photovoltaic and • Passive solar design – For solar water heating installations are centuries, skilled builders have also cheaper per unit of energy than designed homes and other buildings smaller residential installations. that take the best possible advantage of solar energy. “Passive” solar • Many businesses present unique design can contribute to the overall opportunities to tap solar energy: efficiency of a building, reducing the need for energy for lighting, heating o Walmart’s use of skylights in and cooling. some its big box stores has cut

Building a Solar Future energy costs by 15 to 20 percent powering our transportation system. by reducing the need for electric Toyota, for example, is developing lighting. solar charging stations for its Toyota Prius plug-in hybrid vehicle, due o Laundry facilities, hotels, hospi- on the market in 2011. In addition, tals and even baseball’s Boston America’s vast areas of highways and Red Sox have adopted solar parking lots could house solar panels. water heating to reduce their consumption of natural gas for • New transportation technologies water heating. create new opportunities to use solar power. California’s high- speed rail authority has committed Solar Factories to powering the state’s new rail system with renewable energy, Manufacturing facilities consume vast while major shipping companies are amounts of energy to create heat, much experimenting with the use of “solar of it at temperatures that could be sup- sails” to reduce the environmental plied by solar water heating systems. Food impact of shipping. processors, chemical companies and textile plants are among those that are good candidates for solar energy. For example, Solar Communities a Frito-Lay plant in California uses solar concentrators to provide heat for cooking • Government facilities such as offices, snack foods. At full capacity, the system schools and wastewater treatment replaces as much natural gas as is used by plants, as well as community insti- 340 average American homes. tutions such as churches, are often excellent candidates for solar energy.

Solar Farming • New policy tools enable members of a community to work together to Solar photovoltaics can provide a large finance solar energy installations, share of the electricity needed to operate enabling even individuals without a farm and keep harvested crops cool, and suitable roofs to take part in expand- are especially useful for pumping water, ing solar power. providing irrigation and meeting other needs in remote areas that aren’t easily • Housing developments in Europe reached by the electric grid. Many farms and elsewhere have created neigh- could also take advantage of solar energy borhood-wide solar district heating for heating greenhouses, ventilating barns systems that reduce fossil fuel con- or drying crops. sumption for space heating and water heating by 25 percent or more.

Solar in Transportation Building the Solar Grid • The development of plug-in vehicles—both plug-in hybrids and fully • Concentrating solar power plants can electric vehicles—will allow renew- replace coal and other fossil fuels for able energy to play a larger role in base load electricity generation.

Executive Summary 3 • Since photovoltaics generate energy • Renewable electricity standards best when demand is highest—on (RES), such as those now in place hot, sunny summer days—they can in 29 states, can ensure that utilities reduce the effective peak demand integrate solar into their energy pro- that utilities have to meet, provid- files. Solar carve-outs, which require ing stability to the grid, reducing the that a share of the RES be met with need for expensive new power plants solar energy, can ensure a diversified and transmission lines, and curbing mix of renewable resources and en- air pollution. courage the development of distributed renewable resources. • Photovoltaic cells and solar water heaters distributed on buildings • New financing tools can help in- around the country will reduce the dividuals and businesses absorb the amount of energy that needs to flow large upfront costs of solar instal- from central power plants or energy lations and begin reaping benefits providers to consumers. immediately. Municipalities can use their power to borrow at low inter- • Investing in forms of “smart grid” est rates to finance residential solar technologies can expand the amount installations, which can be paid back of electricity the nation can generate through assessments on property tax from distributed solar power while bills. Utility on-bill financing can maintaining reliable electricity achieve similar aims, while low-in- supplies. terest loans and loan guarantees can help reduce the payback time for so- America can obtain a large share of lar energy investments by businesses. its energy from the sun. But it will not happen on its own. Local, state and • Advanced building codes and stan- federal governments must implement dards can ensure that builders take public policies that remove the barriers maximum advantage of passive solar currently impeding the spread of solar heating and lighting in new build- energy and adopt policies to make solar ings and create new opportunities for energy an important part of America’s integrating solar energy into existing energy future. buildings. Solar-ready building standards guarantee that new homes are • Financial incentives, such as grants, built with solar energy in mind, and tax credits and feed-in tariffs help can be broadened to require that so- to compensate homeowners and lar energy be offered as an option on businessowners for the benefits their new homes. Some states and coun- investments in solar energy deliver to tries have gone so far as to require society and can create a robust early the use of solar energy (specifically, market for solar technologies, build- solar water heating systems) on new ing the economies of scale needed residential buildings. to lower the price of solar energy. To create a stable market, financial • Consistent rules to ensure ac- incentives should be applied con- cess to solar energy are needed to sistently over a long period of time, overcome bureaucratic barriers that instead of as intermittent, on-again can prevent individuals and busi- off-again programs. nesses from using solar power. Solar

Building a Solar Future access laws prevent homeowners’ labeling requirements for buildings associations and municipalities from can ensure that the energy-sav- adopting rules that effectively ban the ing value of passive and active solar use of solar energy, while revisions to energy systems is fully understood permitting rules and utility regula- when properties change hands. tions can reduce the hassle and cost of installing solar energy and ensure • Investments in a solar grid will be that people are compensated fairly needed to fully tap America’s solar for the solar power they supply to the energy potential. A well-designed grid. “smart grid” can ensure that solar power is an asset to the electric grid, • Public education and workforce while limited investments in new development efforts are critical to transmission capacity can help to tap expanding the use of solar energy. the nation’s best solar resources. Public education programs can help answer consumers’ questions about • Research and development pro- solar energy and make it easier to grams can help ease the integration “go solar.” Workforce training can of existing solar technologies, further expand the number of workers with develop emerging technologies with the skills needed to partake in the great promise for the future, and in- dramatic growth of America’s solar vestigate new potential uses for solar energy market. Meanwhile, energy energy.

Executive Summary 5 Introduction

merica’s energy system is all-impor- damage left behind by our consumption tant to our economy, but it is so in- of fossil fuels. Some of that damage is Ategrated into our daily lives that it invisible, such as the health-threatening has become all but invisible to most of us. pollutants that foul our air and infiltrate Few of us ever stop to marvel at the our lungs or the leaking underground oil path that a drop of oil must take from a storage tanks that slowly pollute drinking Saudi Arabian well to the gas tanks of our water. Sometimes the damage is inflicted cars—the drilling technology that allows far away from where most Americans live, the crude oil to be pumped from deep be- appearing as the melting of Arctic ice neath the earth, the pipelines that carry due to global warming, or the filling in that oil to a port, the military power that of a remote Appalachian hollow resulting keeps the shipping lanes open for the tank- from mountaintop mining. As people in ers to transport that oil halfway around America and worldwide have awakened the world to our shores, the giant refiner- to the environmental dangers posed by ies that convert the crude oil into gasoline, fossil fuels, we have built even more and the extensive distribution infrastruc- infrastructure to mitigate those dangers— ture that gets the gasoline into our tanks. from installing scrubbers on coal-fired Similarly, few of us see the immense power plants to training hazmat teams to infrastructure that turns a lump of coal clean up oil spills. mined in Montana into the electricity that Over the course of more than a century, powers a computer in Alabama—the gi- and with the investment of untold ant machines that mine the coal, the trains billions of dollars, America has built that carry it across the country, the mas- an energy system that does a masterful sive power plants that convert it into elec- job of unlocking the energy stored in tricity, the ubiquitous web of wires that underground deposits of fossil fuels and transmit that electricity across great dis- transforming that energy into the heat, tances and through neighborhoods to our electricity and kinetic energy that power homes. our economy. However, that same system Even fewer of us see the environmental does a poor job of taking advantage of the

Building a Solar Future powerful renewable energy sources all and availability of fossil fuels in an era of around us—especially the sun. growing worldwide demand—all of these Indeed, as America has built its econ- are powerful reasons to look for alterna- omy around the expectation of continued tives. And never before have so many good access to cheap fossil fuels, we have turned alternatives been available. our backs on centuries of received wisdom Solar energy has the potential to dra- about how to use the sun’s energy to our matically reduce our use of fossil fuels in benefit. Once upon a time, skilled builders virtually every area of our economy. It is oriented homes to take maximum advan- clean, safe, ubiquitous and flexible. It is tage of the sun and wind, installed awnings also increasingly cost competitive with and deciduous trees to block the sun’s rays conventional sources of energy. in summer, and used light-colored build- Taking advantage of America’s limitless ing materials to reflect solar energy in hot solar energy potential would deliver great climates. Today, many of these practices rewards to the nation, but it won’t be easy. have been eschewed in the quest for mass- It will take creativity to transform our en- produced “cookie cutter” homes that are ergy system from one based on fossil fuels cheaper to build but more expensive to and centralization to one that efficiently operate, solidifying our dependence on reaps solar energy at the places where that fossil fuels. energy is used. Realizing a “solar future” Cheap fossil fuels have also caused us for America will require new habits of to turn our backs on newer technologies thinking, new policy tools, and, most of to tap the power of the sun. Solar water all, a roadmap of where we are headed. heaters have been standard equipment on The immense infrastructure that brings homes in some parts of the world for de- fossil fuels to our homes is a potential cades (and were common in parts of the obstacle to that transformation, but it is U.S. in the early part of the last century), also an inspiration. If America and the yet are rare in the United States today. For world can surmount the challenge of us- years, technologies such as solar photovol- ing a drop of oil from a desert half a world taic panels and concentrating solar power away to power a trip to the grocery store plants have stood ready to play an impor- in Omaha, how much easier must it be to tant role in supplying us with energy, only harness the heat and light that strikes our to falter for lack of consistent government homes every day? support of the kind enjoyed by the fossil The time has come for America to em- fuel industry. brace a vision of a clean energy future, Today, America is experiencing the with solar energy as a key contributor, and downsides of our dependence on fossil fu- to lay the groundwork for that future by els as never before. The ominous specter adopting smart public policies that can of global warming, the continued pollu- transform our economy and preserve our tion of our air and water that results from environment. fossil fuel use, and worries about the cost

Introduction 7 Why Solar? Why Now?

merica urgently needs to reduce our fuels for home, business and transporta- consumption of fossil fuels to pro- tion use.2 For every dollar that an Ameri- Atect our environment and ensure can household spends each year, about 9 our continued economic prosperity. Solar cents goes toward the purchase of energy, energy can replace many of the fossil fu- most of it for fossil fuels.3 els we currently use to power our homes, Perhaps the greatest challenge posed by communities, farms, businesses, factories our dependence on fossil fuels is the dam- and cars. age those fuels do to our environment and our health. Fossil fuel combustion contributes to the formation of smog and soot, which damage the lungs and make the air in areas housing 186 million Americans unhealthy to breathe.4 The burning of America’s Dependence on coal contributes to the formation of acid Fossil Fuels: Harming Our rain and contaminates our waterways with mercury, a neurotoxin that makes fish in Environment and many waterways unsafe to eat. Threatening Our Future The toll of fossil fuel extraction on The vast majority of the energy America our environment is widespread and se- uses each year, 84 percent of it, comes vere—from oil spills off our coast to the from fossil fuels.1 Coal, oil and natural gas fragmenting of natural habitat for natural are inherently limited resources, requiring gas drilling. Coal mining in the 19th and tremendous effort and expense to discover, 20th centuries fouled approximately 9,000 extract, process and distribute. Fossil fuels miles of rivers in Appalachia with acid mine represent one of the most important day- drainage.5 “Mountaintop removal” mining to-day expenses for American families and in many of these same areas threatens new businesses—in 2006, the United States environmental damage in the 21st century. spent nearly 7 percent of its gross domes- No issue, however, poses as great a tic product, or $921.2 billion, on fossil long-term threat to our environment as

Building a Solar Future global warming. Global warming is un- average temperatures below 2° C, emis- derway, and its impacts can already be felt sions of global warming pollutants must in the United States and worldwide. Al- peak soon and be cut by roughly half by ready, plants and animals are being forced mid-century. The United States, as the northwards by rising temperatures, put- world’s second-largest emitter of global ting populations at risk.6 In the oceans, warming pollution, and the country re- rising temperatures and acidity are rap- sponsible for more of the global warming idly destroying coral reefs and threatening pollutants in the atmosphere than any other ecosystems.7 other, must go farther and faster than the Disturbing though these changes are, world as a whole. they are only a fraction of what will take Achieving these emission reductions place if we fail to rein in our emissions. will require us to use every resource avail- In the few years since the Intergovern- able to us to decrease our use of fossil mental Panel on Climate Change issued fuels. While energy efficiency will likely its most recent report, global warming’s account for the first major steps we take harmful effects have already outpaced the towards averting a climate crisis, we will scientists’ worst predictions.8 Worse yet, also need to replace existing dirty energy scientists report that we are approaching sources with new clean fuels. Solar ener- “tipping points” at which the effects of gy—in the form of solar power plants, so- global warming will accelerate, and efforts lar panels and collectors on our homes and at mitigation become more and more dif- businesses, and new buildings that take ad- ficult.9 vantage of the sun’s energy through their If global warming emissions continue design—will be a critical tool for achiev- unabated, global temperatures may in- ing this goal. crease by as much as 11.5° F and sea levels could rise 6.5 feet by the end of the century, causing massive flooding and displace- ment.10 If global warming is allowed to take place on this scale, the consequences will likely include the extinction of as much as Solar Energy: 70 percent of all species on earth, intense A Powerful Solution heat waves with temperatures reaching Solar energy technologies are a power- 120° F in large parts of the United states, ful solution to reduce the environmental and droughts across as much as a third of damage caused by our dependence on fos- the globe.11 sil fuels. In 2008, our nation emitted more than Life-cycle analyses of solar photovoltaic 7 billion metric tons of global warming (PV) systems show that they dramatically pollution, the vast majority of it result- reduce emissions of global warming polluting from the production and use of fossil ants and smog- and soot-forming pollut- fuels.12 In order to preserve a reasonable ants compared with fossil fuels, even when chance of keeping the increase in global the emissions created in the manufacturing

The decision to install solar PV yields 26 to 27 years of true fossil fuel-free electricity.

Why Solar? Why Now? of the PV systems are included. For some dramatically reduce fossil fuel use and PV technologies, life-cycle emission reduc- emissions. According to one analysis, a tions are as high as 89 to 98 percent.13 concentrating solar power plant generates According to the U.S. Department of enough energy in its first five months in Energy, the “energy payback” time for a operation to “repay” the energy used to PV system—the amount of time it takes build the plant.15 to save as much energy as was used to pro- Solar energy can dramatically reduce duce the system—ranges from three to our use of fossil fuels and our emissions four years and is decreasing over time. As- of global warming pollutants. There are suming a system lifetime of 30 years, the many solar technologies that can play a decision to install PV yields 26 to 27 years role in America’s energy system, and many of true fossil fuel-free electricity.14 ways to use those tools to help power our Concentrating solar power plants also economy.

10 Building a Solar Future Building a Solar Future for America: The Tools

hen most people think about so- envision when considering solar power— lar energy, they think of solar and “thin films,” inexpensive sheets of Wpanels sitting on rooftops, or, less material that can be used in panels or be frequently, mirrors spread out across the spread across roofs and other architectural desert. While these technologies are im- features. Crystalline silicon PV panels are portant, they represent only part of the frequently more expensive, but are more potential for solar energy to transform our efficient at converting sunlight into elec- energy system. tricity, and can be mounted on a roof or The sun is a ubiquitous and tremen- can stand alone on top of a pole or piece of dously flexible source of energy. Solar en- machinery. Thin films, while less efficient, ergy can be converted directly into elec- cost less and require less silicon to pro- tricity, stored as heat for later conversion, duce. They can also be integrated unob- or used in the forms—light and heat—in trusively into buildings—rolled out across which it arrives. It can be captured cen- rooftops or walls as a barely visible sheet. trally and then distributed to users, or col- PV systems are easily transportable and lected right where it will be used. There installable, and can be used to generate are many technologies and tools that can electricity where it will be used, even at be used to harness solar energy. locations the electric grid doesn’t reach.16 PV is also modular, so installations can be scaled to the appropriate size for a given use.17 PV’s scalability allows it to be used for both large-scale power plants and to power handheld calculators, and it dis- Photovoltaic Power tinguishes PV from almost every other Photovoltaic (PV) cells use the sun’s radia- power generation technology—imagine, tion to generate a direct flow of electric- for instance, a coal-powered calculator, ity. The two most common forms of PV or a nuclear-powered roadside cell phone are crystalline silicon PV—the traditional, call-box. self-contained PV panels most Americans PV has other advantages as well. PV

Building a Solar Future for America: The Tools 11 Solar photovoltaics help to power the Indian Pueblo Cultural Center in Albuquerque, New Mexico, one of many community buildings that can make good use of solar energy. Credit: Sandia National Laboratories

is one of the few power-generating tech- for PV systems far outstrips the number nologies that is a good fit for urban- ar installed today. America’s residential and eas—it produces no air pollution and can commercial rooftops, for example, could be installed on buildings, parking lots and host as much as 712 gigawatts of solar other developed areas without interfering panels (roughly 700 times the capacity of with human activities. As a result, there all solar installations today) if every inch is no additional land required for siting a of suitable rooftop were to be covered, distributed PV system. PV systems, un- enough to produce roughly a quarter of like steam generators, do not use water America’s electricity using current tech- for anything other than routine cleaning nologies.19 Central-station photovoltaic of the panels, making them a good fit for systems in sunny areas, PV systems along areas with low water availability. And PV roads or over parking lots, and PV instal- systems generate the greatest amount of lations at factories could add to this total. electricity at the times when it is most needed, particularly hot, sunny summer days. Photovoltaic installations are increasing rapidly in the United States. Between Concentrating Solar Power 1998 and 2008, the amount of installed PV Whereas PV technologies produce elec- capacity increased by a factor of more than tricity only when the sun is shining on 10, from 100 megawatts (MW) to 1,173 them, concentrating solar power (CSP) MW.18 (See Figure 1.) But the potential can provide a steady and uninterrupted

12 Building a Solar Future Figure 1. Installed Photovoltaic Capacity, United States20

1,400

1,200

1,000

800

600

400

200 CumulativeInstalled Photovoltaic Capacity, U.S. (Megawatts) 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 stream of power by storing the sun’s heat have been reliably producing power for and using it to power a generator. These decades, while at least six new plants have systems are particularly suitable for large come on line since 2006. 22 power stations, but can also be deployed Concentrating solar can also be used for smaller scale on-site generation. on a smaller scale, with satellite dish-like All concentrating solar power technol- mirrors focusing energy on a small receiv- ogies use mirrors to focus light on a re- er that contains a heat exchange engine. ceiver to heat a fluid. Once heat has been These systems have less storage capability, captured, it can be stored until it is needed, but are also more modular, requiring less or it can be used immediately to power a access to vast open spaces. steam generator or heat engine. Large-scale concentrating solar plants can take several forms—either focusing heat on a single central tower, or on long pipes that carry heated fluid to a central Solar Water Heating collector. These technologies are versa- Solar water heating systems are among tile enough to use as a stand-alone power the simplest uses of sunlight for energy. plant, as a preheating system for the wa- In solar water heating systems, water (or a ter used in fossil-fuel plants, or in a hy- heat transfer fluid) is piped to the roof of brid configuration alongside existing fossil a building, where it is heated by traveling fuel generators.21 CSP plants in California through sunlight-absorbing pipes. Because

Building a Solar Future for America: The Tools 13 cloudy days. Overall, solar collectors can typically provide for 50-80 percent of a building’s water heating needs.26 Solar water heating has already become widely used in some countries. In Israel, for example, 90 percent of homes currently use solar water heating and Hawaii has recently adopted a standard requiring solar water heating on all new homes built in that state, though with some exceptions.27

Passive Solar Lighting Solar “power towers” such as this one in California use arrays of mirrors to focus and Heating sunlight on a central receiver, and can incorporate thermal storage, which enables the For most of human history, skilled build- plant to deliver electricity even at night. Credit: Sandia National Laboratory ers designed buildings to take advantage of the sun for lighting and heating. That changed in the mid-20th century as builders began to rely on cheap energy to make capturing heat from sunlight is simple and up for deficiencies in a building’s design. efficient, solar water heating systems can A renewed focus on energy conservation, absorb as much as 87 percent of the energy however, has brought the practice of day- radiated at a given section of roof.23 Solar lighting and passive solar heating back into water heating can be used for swimming the forefront of architectural thought. pools, to replace conventional residential In its simplest form, daylighting is the and commercial hot water heaters, and in art of bringing a comfortable amount of larger-scale industrial settings. light into living and work spaces during A range of collector types is avail- the day, without causing excessive glare able for heating water with solar energy. or heat transfer through windows. The least expensive systems raise water Lighting designers can use windows, temperatures only about 18° F above the skylights, reflective surfaces, and exterior ambient air temperature and are typically features that direct or diffuse light to used to heat swimming pools.24 A slightly illuminate rooms and decrease the need more expensive collector can heat water for artificial lighting.28 A well daylit space to temperatures suitable for a home hot will have comfortable levels of light in all water system.25 These collectors can func- different areas, throughout the day, and tion in all climates, and in warm climates all year round. Daylighting can reduce they can be made less expensive by storing total building energy costs by as much water on the roof near the collector. The as one third.29 Solar lighting systems most expensive collectors are designed for can be augmented by electric lights that applications requiring extremely hot wa- are controlled automatically by dimmer ter, or for heating large volumes of water switches and that supplement sunlight for commercial or industrial use. Solar when necessary. Advanced systems, water heating systems should have a con- meanwhile, can use fiber optic cables to ventional fuel backup to provide heat on deliver light from collectors on the roof

14 Building a Solar Future to fixtures that also hold electric lights, automatically decreasing the amount of electricity used as appropriate.30 Passive solar heating, much like passive solar lighting, aims to admit solar energy to a building when it is needed, while keeping it out when it is not. South-facing windows that admit winter sunlight (usu- ally positioned so as to be shaded during the summer), skylights, and air circulation features that move solar heat through the house all assist in reducing the need for Passive solar design techniques such as daylighting can active heating.31 Passive solar features can create attractive living spaces while reducing electric- Credit: U.S. Department of En- also include sunspaces such as enclosed ity consumption. ergy Solar Decathlon, reprinted under Creative porches, which provide a pocket of warm Commons license air outside the building envelope. Thermal storage walls (dark-colored walls behind glass that can conduct heat to the interior) can store solar energy during the day and release it at night.32

While solar heating is fairly intuitive, it may be more surprising to learn that solar energy can also be used to cool buildings, Active Solar Heating even without being converted into elec- and Cooling tricity. In a solar cooling system, air is cy- Solar heat can also be captured through ac- cled through a dessicant material that pulls tive systems, either for heating residential the humidity out of the air. That material and work spaces or for industrial purpos- is then baked dry by solar heat—captured es. The collectors used for these systems just as in a solar heating system—allow- generally resemble those used for solar ing it to be reused. The dry air can then hot water heaters; either glazed plates (for evaporate water from another source, such most home space heating applications) or as an indoor fountain, which cools the evacuated tubes (for commercial, industri- air—just as the evaporation of sweat cools al, or solar cooling applications) are used.33 a human body. Such systems can save ap- In some cases, solar space heating and wa- proximately 50 percent of the energy used ter heating systems can be combined. to air condition a building.35 They are also When used for home heating, active at their most effective on sunny days when solar systems generally provide for 40-80 the need for air conditioning is likely to be percent of a building’s heating needs.34 greatest.

Building a Solar Future for America: The Tools 15 Solar water heating systems, which are common in parts of the world, can provide 50 to 80 percent of a building’s hot water needs. Credit: VELUX/ESTIF

16 Building a Solar Future A Solar Future for America

olar energy can be integrated into vir- What a Solar Home Looks Like tually every part of American life—the Solar homes use the energy of the sun to Shomes we live in, the offices where avert the need to burn fossil fuels or tap we work, the farms and factories that pro- electricity from the grid. New homes have duce the products we buy, and the schools the greatest potential to take advantage of where our children learn. With creativity solar energy, but solar technologies can and sound public policy, solar energy can also be integrated easily into many exist- make a major contribution to America’s ing homes. energy future. New Homes New homes are the easiest places to take maximum advantage of the sun’s energy. Solar energy can play an important role in Solar Homes the construction of “zero-energy homes,” There are more than 128 million hous- which produce as much energy as they use ing units in the United States, includ- over the course of a year. ing more than 80 million single-fam- Most of the features that distinguish ily homes.36 Virtually all of these homes a “solar home” are subtle. Well-posi- consume fossil fuels for heating, lighting, tioned windows and skylights decrease air conditioning and other purposes, yet the amount of time that electric lighting only a tiny fraction currently produce en- is needed each day. Thoughtful building ergy from the sun. Tapping America’s full orientation and the proper use of shading potential for powering our homes with elements—such as overhangs, awnings or the sun could dramatically reduce our deciduous trees—allow warming sunlight dependence on fossil fuels and our emis- in during the winter while keeping it out sions of global warming pollution while during the summer. “Thermal mass” ele- also creating thousands of installation ments, such as stone walls or floors, can jobs that can’t be outsourced. be used to store the sun’s warmth during

A Solar Future for America 17 the day and release it at night. Replacing generate $5 billion worth of revenue by conventional wood-frame walls with ther- 2015, and which will take less than half as mal mass walls made of concrete, for ex- long to install as conventional solar pan- ample, could reduce whole-house energy els.40 Other companies are developing consumption by 6 to 8 percent.37 similar products. Not only are many of these design el- Home builders with standardized so- ements energy savers, but many of them lar home designs can incorporate solar also add to the beauty and comfort of a energy features less expensively than the new home. owner of an existing home, and may be able to shave costs further by ordering solar components in volume and devel- 38 Figure 2. Elements of a Passive Solar Home oping a trained workforce. California, for example, has seen the development of new residential subdivisions—amounting to hundreds of homes—that incorporate solar technologies either as an option or a standard feature.41 Residents of solar homes have generally been happy with their purchase. A 2006 survey of California solar home owners found that 92 percent would recommend the purchase of a solar home to a friend.42 Builders of solar homes also benefit because solar homes sell faster than conventional homes.43 When combined with advanced energy efficiency technologies, passive and active solar energy can dramatically reduce fossil fuel consumption in New homes also provide an opportu- homes, while saving homeowners money. nity to take full advantage of “active” solar A study in the U.S. Southwest estimated energy technologies such as photovoltaics that “zero-energy” homes could reduce and solar water heating systems. Instead net energy consumption by 60 percent or of having to retrofit a building’s electricity more. These homes would cost an added or plumbing systems to accommodate so- $15,000 to $20,000 for construction, but lar energy, solar technologies can be built in all cases the homeowner would save into new homes right from the start, and more in energy bills than was spent on the the home and surrounding vegetation can energy-saving features.44 be deliberately designed to maximize the Nor do solar homes only work in the solar energy potential of the home. Southwest or other sunny regions of the Installing a solar water heater in a new United States. A Massachusetts state task home, for instance, can cost just half of force, for example, concluded that the en- what it would to install one in an existing ergy savings of a zero-energy home in that home.39 Photovoltaics, meanwhile, can be cold-weather state more than compensate incorporated into building materials so for the additional upfront cost. In fact, in- that they require little technical expertise corporating passive solar features can ac- to install. In October 2009, Dow Chemi- tually reduce some of the costs associated cal announced that it would be rolling out with building a new home by allowing for a line of solar shingles that it expects to the installation of smaller, less expensive

18 Building a Solar Future heating and air conditioning systems.45 equator, which receive direct sunlight Some building design experts are con- throughout most of the day. Current templating “Energy-Plus” building de- estimates suggest that 35-40 percent signs that make homes net energy produc- of residential buildings are suitable for ers. These homes are built using extremely photovoltaic panels.47 airtight construction materials and tech- Solar water heaters typically decrease niques and use designs that take optimal the amount of natural gas or electricity advantage of sunlight. The international required for water heating by 50 to 80 Passive House design standard, for ex- percent.48 A National Renewable Energy ample, saves up to 90 percent of the en- Laboratory study estimated that 50 per- ergy used in home space heating.46 These cent of residential buildings nationwide buildings could be paired with active so- could use solar water heating systems.49 As lar systems to be net sources of energy to with solar photovoltaic panels, solar water their communities. heating systems—in which a rooftop collector is used to pre-heat water for house- Existing Homes hold use—can be installed in any climate, Existing homes may not have been built although different types of systems work to take advantage of the sun, but many are better in different parts of the country. good candidates for incorporating solar Solar water heating systems are smaller, energy. technologically simpler, less expensive, Photovoltaic panels can be installed on and more efficient at capturing the energy almost any roof, but they are most effective at sunlight than solar PV panels. Installing on flat or lightly-sloped roofs facing the a solar water heater in an existing home

Solar homes—such as those in this California development—are increasingly common and sell more rapidly than conventional homes. Credit: Sacramento Municipal Utility District

A Solar Future for America 19 costs about $6,000.50 State and federal in- to expand its production of solar centives can defray some of the cost of in- electricity in the years to come.53 stalling solar water heaters. • Warehouses also use a great deal of energy on lighting, and can benefit from incorporating passive solar lighting features. Temperature-controlled warehouses can save energy Solar Businesses by incorporating appropriate passive America’s commercial buildings—its solar heating or cooling features.54 big-box stores, strip malls, hotels, office buildings, and the like—are just as depen- • Laundromats use a great deal of dent on fossil fuels as our nation’s homes. energy to heat both water for washers Commercial buildings are responsible for and air for dryers, and can use solar nearly roughly 14 percent of the nation’s energy for both of these purposes. 51 energy consumption. For certain types For example, the World’s Largest of businesses, fossil fuel expenditures can Laundromat in Berwyn, Illinois, be a major business expense. A growing installed a solar water heating system number of firms nationwide are coming designed to produce 2,400 gallons of to recognize that adopting solar energy hot water every day after natural gas makes good business sense, as well as good prices spiked in 2001.55 Other kinds environmental sense. of businesses and institutions with large laundry facilities, such as pris- What a Solar Business Looks Like ons and hotels, can use solar energy America’s commercial sector is extraor- in a fashion similar to laundromats. dinarily diverse, with businesses of many types ranging in size from mom-and-pop • Restaurants and other businesses that stores to giant office complexes. Differ- serve food to many customers can use ent kinds of commercial buildings present solar water heating for their water different kinds of opportunities for using heating needs. Baseball’s Boston Red solar energy. Businesses that use a particu- Sox, for example, installed solar water larly large amount of energy for any one heaters on the roof of Fenway Park, purpose have the potential to take advan- reducing consumption of natural gas tage of the economies of scale described for water heating at the facility by for homes in offsetting that need with so- more than one-third.56 lar energy. • Businesses and institutions with large • Big box stores are single-story build- public meeting spaces or other open ings and use a great deal of electricity spaces can use 50 percent or more for indoor lighting during the day- of their total energy on heating, and time. By installing just one skylight could use solar heating systems to per 1,000 square feet of store space offset their need for conventional and using dimmable indoor lights, heating.57 Walmart has been able to save 15-20 percent of total building energy costs As with solar homes, newly built com- in many of its superstores.52 In addi- mercial buildings can be designed to in- tion, Walmart has installed solar PV corporate passive and active solar fea- systems on 20 of its stores and plans tures from the very beginning, reducing

20 Building a Solar Future their cost. A 2007 assessment of several categories of “green buildings” (some of which incorporate passive or active solar energy systems), for example, found that there was no significant difference in the cost of building green versus non-green buildings.58 A similar analysis of buildings meeting the Leadership in Energy and Environmental Design (LEED) standards found that buildings meeting the criteria of the lowest three tiers of the LEED program cost an additional 2 percent or less to build, while cutting energy consumption by 28 to 48 percent.59 Commercial buildings are much more likely than residential buildings to have flat roofs, meaning that many of them can Workers install solar panels on the roof of the supervisor’s office at Wayne National Forest in Ohio. Many office buildings can take advantage of solar energy. Credit: play host to properly oriented photovoltaic Alex Snyder, Wayne National Forest panels or solar water heating systems. A report for the National Renewable Energy Laboratory estimated that 60-65 percent of commercial roof space nationwide would benefits in reduced energy costs. Feed-in be suitable for PV panel installation.60 tariffs and third-party financing tools can Many businesses have larger roofs, and help to surmount these obstacles. (See use more energy, than residential energy page 43.) customers. This makes it possible for them to take advantage of the significant economies of scale that come with purchasing and installing active solar installations of larger sizes. Large photovoltaic systems with between 500 and 750 kilowatts (kW) Solar Factories of capacity, for instance, cost about 30 per- Historically, manufacturing facilities have cent less per Watt of capacity than small been thought of as environmental pollut- residential systems.61 The high-efficiency ers, not potential contributors to a green heat collectors often used for commercial future. But America’s manufacturing sec- solar heating applications, meanwhile, can tor has a great deal to gain from a transi- be installed in large numbers and coupled tion to cleaner sources of energy. with mirrors to enhance their effective- Manufacturing is extremely energy in- ness. These measures can reduce the per- tensive. Food processing facilities, cement square-foot cost of these high-efficiency plants, steel mills and other industrial fa- collectors to 50 percent or more below the cilities use energy on a vast scale. They are average cost of residential units.62 responsible for roughly 28 percent of the One potential barrier is that commer- global warming pollution emitted in the cial establishments are disproportionately United States.63 Reducing fossil fuel con- likely to rent their buildings, creating sumption in factories is not just a matter of potential “split incentive” problems, in environmental concern. American manu- which builders bear the cost of installing facturers face the challenge of international solar energy systems but tenants reap the competition—reducing energy costs is just

A Solar Future for America 21 one way to remain competitive. in a kiln obviously requires process heat, Solar energy cannot replace all the en- but so does distilling ingredients in a phar- ergy that is used by America’s manufactur- maceutical plant, pasteurizing milk in a ing sector, but it can make an important food processing plant, or bleaching cloth contribution to meeting the energy needs at a textile mill. of many of America’s factories. Uses of process heat are classified by the temperatures required. Some processes take place at temperatures well What a Solar Factory Looks Like above what can be achieved economically America’s manufacturers use energy for a using solar energy, but many others take wide array of purposes. Electricity is used place at lower temperatures. About 30 to light shop floors and power machinery, percent of process heat is used at “low” fossil fuels are burned in boilers to create temperatures—below the boiling point steam and process heat and to generate of water—and another 27 percent is used electricity. Solar energy can help to alle- at “medium” temperatures—between 100 viate energy demand in several of these and 400° C.65 Solar heat is most useful for areas. processes occurring at less than 250° C.66 The creation of “process heat” uses In certain key industries—such as food, more energy in America’s manufacturing textiles, and paper—60 percent or more of sector than any other single activity.64 process heat is needed at these tempera- Melting iron in a mill or cooking cement tures.67 Solar water heating is potentially

Audi installed a solar cooling system (above) at its training center in Ingolstadt, Germany. Credit: Solahart/ ESTIF.

22 Building a Solar Future well-suited to several uses of industrial pianos, while during the winter the system heat, including cleaning, drying, preheat- helps heat the facility.74 ing of boiler water, and sterilization.68 Solar photovoltaics can be used to help Industrial plants that use large amounts meet the electricity needs of factories. of process heat at low and medium tem- Like commercial buildings, large factories peratures can potentially install large ar- are likely to have flat roofs and be exposed rays of solar thermal collectors to provide to sunlight. Installing photovoltaics on that heat. Worldwide, approximately 90 factories can reduce demand for electric- solar process heat systems are currently ity, provide power to drive motors and in place, including several in the United industrial machinery, and deliver electric- States.69 The largest solar process heat ity back into the grid during peak demand system in operation in the United States times on hot summer days. is located at a Frito-Lay factory in Cali- Passive solar design can also reduce en- fornia. It uses a 5-acre field of solar con- ergy demand in factories. About 5 percent centrators to create steam, which is used of the energy used in the manufacturing to heat the oil used to cook the company’s sector is actually used for lighting and cli- SunChips brand of snack foods.70 At full mate control in workspaces.75 Passive solar capacity, the system can produce 14.7 bil- design elements such as daylighting can re- lion BTU of energy per year, equivalent to duce the need for artificial light. Ford Mo- the annual natural gas use of 340 average tor Company’s Rouge Center truck plant American homes.71 in Dearborn, Michigan, for example, was The industries with the most existing redesigned to incorporate daylighting of solar process heat plants are food, chemi- work areas, augmented by well-controlled cals, transport and textiles.72 The kinds of electric lights.76 solar heat collectors used can vary with the The use of solar energy in industry can temperatures needed, and with the scale of avert the consumption of fossil fuels, while the application. Rooftop collectors similar providing a hedge against volatile fossil to those used for residential hot water are fuel prices for energy-intensive industries. appropriate for some industrial applica- The vast amount of energy used in indus- tions, while large-scale collector arrays try means that the potential for energy similar to those used for concentrated savings and emission reductions is large. A solar power plants can serve large scale, study by the International Energy Agency, high temperature uses. For fairly low tem- for example, estimated that solar process perature uses, process heat can actually be heat could provide for roughly 4 percent generated at the same time as electricity of industrial heat demand, reducing con- through the use of photovoltaic/thermal sumption of fossil fuels.77 collector arrays, which capture the waste The expansion of solar energy use in heat generated by sunlight striking photo- industry faces unique hurdles, however. voltaic panels.73 Solar process heat, for example, seems like Solar process heat is just one of many a perfect fit for many industries that rely opportunities to tap solar energy in indus- on hot water—industrial facilities are hun- try. The Steinway & Sons piano factory gry for options to reduce energy costs and in New York City, for example, recently the technology to provide solar hot water installed the world’s largest solar cooling is relatively cost-effective and technologi- system. During the summer, the system cally proven. cools and dehumidifies the factory, - pre However, industrial facilities, like other venting moisture from affecting the preci- businesses, are often driven by short-term sion parts of the company’s world-famous economics, rather than the potential to

A Solar Future for America 23 generate energy savings over the long sector, and the United States could follow term. A mid-1990s review of cancelled so- suit.79 lar process heat projects in the U.S. found that two projects were rejected by companies because they sought a three-year payback time, while the proposed projects delivered payback in 4.4 and 5.2 years, re- Solar on Farms spectively.78 In the 1930s, the United States brought In addition, integrating solar water electricity to remote towns and dwellings heating into an existing industrial plant across the country through rural electrifi- can be technologically challenging—es- cation—one of the signature accomplish- sentially requiring the re-engineering of ments of the New Deal. Access to cheap key processes. Resolving those issues re- energy, however, has also resulted in many quires the existence of experts trained in tasks that were once carried out using so- integrating solar energy into industrial lar energy—such as crop drying—being processes. Unfortunately, the solar process shifted to fossil fuels. heat industry in the United States is rela- Agriculture represents only a small por- tively undeveloped. The European Union tion (approximately 1 percent) of America’s is working aggressively to develop markets total energy consumption.80 But, for indi- for and expertise in the solar process heat vidual farmers, fossil fuel costs can repre-

P-R Farms in California’s San Joaquin Valley uses the electricity created from a photovoltaic system to power its cold storage and packing operations, resulting in a dramatic reduction in monthly energy bills. Credit: PowerLight

24 Building a Solar Future sent a large share of their total expenses. fuels for some greenhouse and crop drying Farmers spent $28.8 billion on energy in applications. Many greenhouses that derive 2003, about 14 percent of their produc- growing light from the sun, but heat from tion expenses.81 gas or propane, could be replaced with The distributed, modular nature of buildings that rely on passive solar heat- solar energy makes it uniquely suitable ing for much of their needs. These passive to provide electric power and heat on solar greenhouses are oriented to capture farms and ranches around the country. more direct sunlight from the south, and Farms and ranches may need electricity use thermal mass and insulation to store for pumps and fences and on-site pro- heat from the day through the night.83 In cessing operations, space heating for warmer climates, crop drying can be per- barns and greenhouses, and hot water formed in sheds with glazed south-facing for cleaning at locations where running walls that admit heat, requiring no active electric wires from the grid or frequent- heating system.84 ly refilling fuel tanks can be inconve- Active solar heating is most useful on nient and expensive. Photovoltaic panels farms for heating barns. Barns contain a and solar heat collectors, which require large volume of air, and also need more minimal maintenance, no refueling, and ventilation than many large buildings, no connection to a grid, can provide a because of the dust and livestock emis- simple and economical solution. sions that quickly build up in them.85 Solar heating systems can replace gas or propane heaters in barns, and can also be What a Solar Farm Looks Like used to promote air circulation during the Solar energy is already commonly used on summer. Active heating systems can also farms for remote applications. Photovol- be used for crop-drying applications, but taic panels, for instance, are often used for are most cost-effective for this purpose powering water pumps in remote pastures. when the solar collector provides heat These PV-powered pumping systems cost both to a drying shed and other build- a total of $2,500 to purchase and install, ings, as needed.86 and operate completely independent of the Farmers who need to clean barns or grid.82 Solar electricity can also be used to machinery use a significant amount of power electric fences, irrigation systems, energy for heating water. Dairy farms and building machinery. These remote so- in particular (which have both barns and lar systems, while small, can deliver out- milking machines to clean on a regular sized environmental benefits, since they basis) need large energy inputs for water often replace inefficient and highly pollut- heating—as much as 40 percent of the ing diesel generators. farm’s total energy use.87 A solar water There are, however, many other poten- heater can replace half the fossil fuel used tial applications for solar energy on farms. for water heating, preventing emissions Space heating and ventilation, for exam- and saving money.88 ple, are important on many farms, pro- Some farms are adopting photovolta- viding winter heat for animal barns and ics to provide electricity to keep harvested greenhouses and keeping the air in animal crops cool and to run equipment. As of enclosures free of dust, gases and odors. early 2009, more than 50 California win- Farmers also use heat to dry crops—a tra- eries had installed solar panels, with doz- ditional role for solar energy that is now ens more planning to follow suit, taking sometimes performed by heat from fossil advantage of California’s abundant sun- fuels. Passive solar heat can displace fossil light to help power their operations.89

A Solar Future for America 25 Solar in Transportation them roads and parking lots.90 Most of this area is unshaded and has little current The phrase “solar cars” brings to mind use other than for storing or transporting images of toy-store science projects and cars, meaning that it could easily be used experimental, Batmobile-style vehicles. for generating solar energy. But any transportation vehicle—a car, Finally, the hundreds of millions of truck, train or even boat—can be a “solar” cars on America’s roads could someday vehicle, so long as it is capable of being help expand the use of renewable energy powered by electricity, and that electricity sources such as solar energy. Plug-in cars comes from solar power. can allow for the short-term, distributed America has many reasons to look for storage of electricity in vehicle batteries, alternative sources of energy for its trans- providing a source of emergency power to portation system. The nation’s dependence smooth out the peaks and valleys of elec- on petroleum has severe environmental, tricity supply and demand. economic and national security implications. Shifting more of America’s transportation system to operate on electricity What Solar Transportation would enable the nation to use a wider Looks Like variety of fuels, including solar power and Small solar panels are increasingly com- other forms of renewable energy. mon sights along highways across the America’s transportation system also United States, providing electricity for represents a powerful, if less obvious, set roadside signs, emergency call boxes and of opportunities for the utilization of solar other roadside equipment without the power. The nation’s transportation system need to operate generators or run wires takes up a tremendous amount of land. to distant locations. States such as Oregon According to one estimate, approximately are going further by installing photovolta- 43,000 square miles of land in the United ic arrays designed to power all of the lights States—an area roughly the size of Ohio— at a highway interchange.91 is covered by impervious surfaces, most of But these applications account for only a tiny portion of the energy used in powering the nation’s transportation system, the vast majority of which goes toward moving vehicles. The introduction of “plug-in” vehicles—electric vehicles and plug-in hybrids—could enable solar power to make a meaningful contribution toward powering our transportation system. Plug-in vehicles are similar to today’s hybrid-electric vehicles, which store the energy captured by regenerative braking and use that energy to help power the vehicle. However, plug-in vehicles have larger batteries that can also store electricity drawn from the grid. In a plug-in hybrid, grid electricity augments energy from a Solar garages, such as this one at Arizona State University, shade ve- fossil fuel-powered internal combustion hicles while providing power to the grid, and could someday be used to charge plug-in vehicles. Credit: Kevin Dooley, reprinted under engine. In an electric vehicle, there is no Creative Commons license. internal combustion engine at all; the

26 Building a Solar Future Oregon’s “solar highway” project involves the installation of solar panels along roadsides in the state. Credit: Gary Weber, Oregon Department of Transportation photo/video services vehicle is powered entirely by electricity al warming pollution. Powering plug-in drawn from the battery. vehicles with renewable energy, however, Plug-in vehicles are currently a rarity in dramatically increases their environmen- the United States, but that could change tal benefits.94 within the next couple of years. Several Plug-in vehicles also provide new op- major automakers are working to develop portunities for tapping solar energy and plug-in hybrids—General Motors’ Chev- for integrating renewable energy into the rolet Volt is scheduled to enter the market electric grid. Almost all vehicles spend the in late 2010, and Toyota’s Prius plug-in majority of their day sitting still—often in hybrid will be put out for testing in early exposed parking lots at a place of work. So- 2010 with a full release in 2011.92 Several lar powered charging stations in parking other automakers are exploring plug-in lots would enable drivers to charge their technologies, including the potential for vehicles during the day, while also pro- fully electric vehicles, with the Nissan viding a source of shade to keep vehicles Leaf all-electric vehicle to be introduced cool. Toyota is developing solar charging in late 2010.93 stations for plug-in vehicles in Japan, and Plug-in vehicles make environmen- several companies in the United States tal sense virtually regardless of how the have built solar parking lots that feed clean electricity that powers them is generated. energy into the grid.95 Solar charging has Electric motors are inherently more en- the potential advantage of channeling the ergy efficient than internal combustion direct current produced by solar panels engines. Even with the very dirtiest elec- into a vehicle battery without the need to tricity, electric cars are about equivalent to convert to alternating current—eliminating today’s conventional cars in terms of glob- the loss of energy that occurs when DC

A Solar Future for America 27 power is converted to AC and vice versa. global warming pollution in 2007.99 A In any case, pairing the expansion of plug- major Chinese shipping firm, for example, in cars with solar power installations can is experimenting with the use of “solar give plug-in hybrid owners the option of sails”—large arrays of photovoltaic pan- charging up during the daytime without els—on some of its ships, while a small adding strain to the electric grid. number of solar ferries already ply the wa- In addition to parking lots, highways ters of harbors around the world.100 provide another possible location for solar panels. Oregon is considering the expansion of its “solar highway” program and solar panels have been installed along roadsides in Europe for decades.96 Airports are also proving to be fertile Solar in Communities ground for solar panel installations. Nu- “Going solar” has traditionally been an in- merous airports across the country—individual affair, with pioneering homeown- cluding facilities in Denver, San Francisco ers or businessowners deciding to install and Austin—have installed solar arrays that their own solar energy systems. The ben- provide a share of the power for airport op- efits of solar energy, however, can be even erations.97 Buffer land surrounding runways greater when entire communities work to- also provides large swaths of unshaded area gether to build solar energy systems. that could be used to house solar panels. Some forms of solar energy technol- While electric cars are in the early stag- ogy—such as neighborhood solar heating es of deployment, parts of America’s trans- systems with seasonal heat storage—are portation system are already powered by only practical on the community level. electricity. Subway and light rail systems, Community involvement can also create along with many commuter rail lines and new opportunities for individuals to adopt some intercity train lines, are powered by solar energy, even if their homes are poor electricity. The recent expansion of light candidates for solar panels. Meanwhile, rail systems in cities such as Los Angeles, many community buildings are good can- Salt Lake City, Phoenix and Denver prom- didates for solar energy. ises to shift more travel away from gaso- Moreover, broad adoption of solar en- line-powered vehicles and toward electric ergy in a community can create important transportation. In addition, the nation is economies of scale. The greater the lo- beginning to invest in creation of a high- cal market for solar photovoltaics or hot speed rail network that would likely be water systems, the greater the base of ex- powered by electricity, and leading states pertise that can develop among the many are working to ensure that the electricity individuals and businesses involved in the that powers the system is renewable. Cali- process—solar system installers, electri- fornia’s High Speed Rail Authority, for ex- cians, builders, banks, utilities, etc. In the ample, has committed to generating 100 many American cities, particularly on the percent of the power for the state’s high- East Coast, that face challenges in meet- speed rail system from renewable energy ing electricity demand, intense develop- and has evaluated the potential role of so- ment of solar power can help alleviate the lar power in achieving that target.98 need to build new power plants in densely Solar energy can even help alleviate emis- packed urban areas or build expensive sions from the global shipping industry. The transmission lines to bring in power from shipping industry is estimated to have pro- elsewhere—saving money for ratepayers duced just over 3 percent of the world’s as a whole.

28 Building a Solar Future This solar thermal array, installed at Arnold Schwarzenegger Stadium in Graz, Austria, provides heat for the town’s district heat system. Credit: SOLID/ESTIF

What a Solar Community a profitable use for the steam left over after generating electricity. New York Looks Like City’s system is the largest in the United Solar communities can take many forms. States.101 Denver, Los Angeles, Boston, A few potential ways that solar energy can Chicago and Kansas City are among the be integrated into communities are dis- many other cities with downtown heating cussed below. systems.102 Nationwide, more than 300 universities and 120 hospitals also use dis- Solar District Heating trict energy in the form of heat, cooling A “district heating” system is one in which or both.103 steam or hot water from a central plant is Solar energy can help to power district piped to residential and commercial build- energy systems. In Europe, several hous- ings in a city, neighborhood, industrial ing developments have been built with park or college campus. In other words, solar district heating systems. In these sys- instead of each individual building having tems, rooftop solar collectors heat water, a furnace or boiler, all the buildings in a which is then piped to a central storage district heating system receive heat from tank. The storage tank is typically de- one central power plant. signed with thick concrete walls and bur- District heat has a long history in the ied underground to retain heat for use in United States. District heat systems were times of day when the sun is not shining or built in many American cities to provide even, with the installation of seasonal stor-

A Solar Future for America 29 age, colder months of the year.104 The solar the solar power generated by his or her district heating system in Friedrichshafen, panel.108 A similar program was recently Germany, which uses seasonal storage to launched in Utah.109 supply heat and hot water to more than Some states are working to create new 500 apartments, covers approximately 25 opportunities for community-based solar percent of the neighborhoods’ space heat- power. Colorado legislators have intro- ing and water heating energy needs; other duced a “solar gardens” bill that would solar district heating installations in Ger- enable individual homeowners to partner many provide an even greater fraction of to build, and receive the benefits of, - so home heating or hot water.105 Such systems lar energy systems not located on their are even viable in extremely cold climates. properties.110 Massachusetts has adopted A 52-unit housing development in Alber- a “neighborhood net metering” policy in ta, Canada, will use solar energy to supply which groups of 10 or more individuals in 90 percent or more of the complex’s space a single town can share in the benefits of a heating and hot water needs.106 solar power installation.111 Solar district heating has gotten the greatest traction in Europe, but the largest Solar in Community Buildings such project is currently being built in the Community institutions—schools, church- United States. The 900,000-square-foot es, municipal buildings and the like—are Fletcher Business Park in western North among the largest and most visible build- Carolina will be heated and cooled by a ings in any city or town. Many of these solar district energy system.107 buildings also have unique characteristics Solar energy collectors can also be used that make them particularly well-suited to augment steam production in existing to take advantage of solar energy. Con- district heat systems, reducing the need to sider schools, which are primarily occu- burn fossil fuels. pied during daylight hours and devote one quarter of their total energy consumption Community-Owned Solar Energy Systems to lighting.112 Schools, therefore, provide Two of the biggest hurdles to the installa- an excellent opportunity to take advantage tion of household solar power systems are of daylighting, reducing electricity needs the upfront cost of the system and the lack and creating a more pleasant learning en- of an appropriate rooftop. Homeowners vironment. Most schools also have large who wish to “go solar” have another op- amounts of available roof space, and could tion for using solar power, however—to use rooftop solar collectors for much of go in with their neighbors on a commu- their heating needs. nity-owned solar system. Other community institutions present Across the nation, recent years have similar opportunities: brought a growing movement toward community-owned renewable energy. Re- • Churches and other large community newable energy installations can be built spaces use as much as 60 percent of by institutions controlled by local resi- their energy for heat.113 Solar heat dents, such as municipal utilities, munici- collectors could provide much of this pal governments or electric cooperatives. energy, particularly during daytime For example, in Colorado, an electric co- services. Church office buildings operative offers its customers the ability to frequently have large, flat roofs. lease a solar panel installed on the utility’s property. The homeowner receives a • Libraries, museums, and other public credit on the monthly bill for the value of buildings use significant amounts

30 Building a Solar Future of energy on heat and lighting, and often have large flat roofs available for PV panels or solar heat collectors. Skylights and other passive design features can be used to daylight the top stories of these buildings.

• Wastewater treatment plants are also good candidates for solar energy, with large open spaces that can easily host solar panels to help meet the facilities’ energy needs.

One advantage that churches, schools, President Obama and Vice-President Biden inspect solar panels on the and other public buildings have over ho- roof of the Denver Museum of Nature & Science, one of many com- meowners in installing solar technologies munity buildings that can benefit from solar energy. Credit: White is that they generally expect to remain House, Pete Souza in the same building for decades, which gives them greater certainty that they will receive the full lifetime benefit of any solar project. Additionally, schools, libraries, and government office buildings are owned and operated by the same local of installations decline.114 Moreover, this governments that are often responsible effect is local, meaning that the develop- for extending credit and incentives to ho- ment of a vigorous solar market in a com- meowners for solar projects. By taking ad- munity or state can help bring costs down, vantage of their ability to issue municipal creating a virtuous circle that makes solar bonds at low interest rates, local govern- energy accessible to a greater number of ments can finance solar projects in a way homeowners and businesses. that spreads the costs and benefits of so- Installing large amounts of solar power lar improvements out over the same time in an area can also reduce peak demand frame. for electricity in areas where the grid is strained—reducing the need to construct The Benefits of Solar Communities expensive new power plants or transmis- When many homeowners and institutions sion lines. Because solar photovoltaics in a community “go solar,” the benefits are generate the most electricity at precisely often magnified. the times when electricity demand is high- For example, as a vigorous market for est (hot, sunny summer days), they can solar energy develops in a community, the play a major role in reducing peak demand demand for trained solar energy installers on the electricity system. In New Jersey, increases and the amount of experience for example, 10 megawatts (MW) of solar gained by those installers grows. Instal- power capacity can be counted on to offset lation costs can represent a large share 4 to 7 MW of conventional peak genera- of the total cost of a solar energy system tion, meaning that carefully located solar and reducing those costs is a key step in panels can dramatically reduce the need making solar energy cost competitive. Re- to run expensive “peaking” power plants, search suggests that, as solar installers gain build new power plants, or expand trans- experience and “learn by doing,” the cost mission lines to serve peak demand.115

A Solar Future for America 31 Solar Grid supplying electricity to our homes at times when the sun is not shining and Solar energy, as we have seen, can be cap- delivering solar electricity to places where tured in American homes and business- it is needed. The grid also enables us to es—even entire communities—sharply take advantage of excellent solar resources decreasing fossil fuel consumption. These that are far removed from any source of solar technologies are “distributed”– they demand. are implemented at or near the places Centralized solar power facilities—such where energy is used. Distributed re- as photovoltaic farms and concentrat- sources have many advantages over the ing solar power plants—can augment or current centralized system of generating replace many fossil fuel resources in our and distributing electricity: they do not electricity system, while investment in rely on the expansion of expensive long- “smart grid” technologies can help Amer- distance transmission networks, they are ica better tap the solar resources in our more energy efficient, and, with proper own backyards. integration, they can make a large contribution to the resiliency of the electric grid and reduce the need for expensive peaking Utility-Scale Solar Resources power plants and transmission lines. America’s desert Southwest and other But our existing electric grid can also sunny areas of country possess some of the play a role in moving America toward a best solar resources in the world. The so- solar future. The grid enables us to move lar radiation striking just a small portion power from places where it is not being of the southwestern U.S. contains enough used to places where it is in demand, energy to power the entire nation. There

Parabolic trough concentrating solar power plants, such as this one in California, have the potential to generate large amounts of power in sunny areas of the Southwest and elsewhere. Credit: Gregory Kolb, Sandia National Laboratory

32 Building a Solar Future are several ways to harness that resource. advantage of both distributed and central Concentrating solar power (CSP) plants solar resources such as CSP to take a seri- use mirrors to focus the sun’s rays on a ous bite out of our dependence on fossil central collector fluid, with the captured fuels. Careful location of CSP systems to heat used to generate electricity (or, less minimize environmental impacts, the use commonly, to provide heat for industrial of air-cooled systems that reduce water processes or space heating). CSP plants consumption, and limited investments in have been providing reliable electricity expanded transmission capacity can ensure in California for decades, and a new gen- that CSP delivers the maximum benefits eration of plants is currently in operation, to our environment. under construction, or in the early stages In addition to stand-alone plants, CSP of approval. Six new CSP plants have be- also has the potential to be used in con- gun operation in the United States since junction with fossil fuel power plants. In 2006, with many more—and larger—proj- Florida, a 75 megawatt CSP facility is be- ects in the pipeline.116 In California alone, ing built as part of a “hybrid” power plant developers have proposed more than 10 with an existing natural gas fired genera- gigawatts of concentrating solar power tor.119 Pairing solar energy with conven- projects—an amount roughly comparable tional power generation can reduce fos- to 1 percent of America’s current electric- sil fuel consumption and global warming ity generating capacity.117 Similar levels of emissions while ensuring a steady and reli- solar development have been proposed in able source of electricity to the grid. Arizona and Nevada. In addition to the potential for distrib- The potential for CSP development is uted use on rooftops, photovoltaic (PV) virtually limitless—CSP plants covering modules can also be used in “solar farms” just 9 percent of the area of Nevada could to generate electricity for the grid. Large- power the entire country.118 The most scale PV installations can be built quickly important limitations on the technology to respond to emerging power needs, can stem from its surroundings—specifically, be located optimally in areas with good the difficulty of finding adequate water solar resources, and use very little water, supplies in desert areas, potential conflicts making them a perfect fit in arid regions with sensitive desert ecosystems, and the of the nation. Moreover, installing PV in a challenge of transporting electricity long single location, using standardized equip- distances to population centers. ment on a large scale, can be less expensive But while CSP has some disadvantages than installing the same amount of capac- compared with distributed solar power, ity in bits and pieces on rooftops. it also has some advantages. One major In 2009, the largest PV farm in the na- benefit of CSP is that the heated fluid tion—a 25 megawatt facility consisting of produced by the system can be easily and more than 90,000 solar panels—came on cost-effectively stored (as opposed to elec- line in Florida.120 Another 6,000 mega- tricity, which requires costly batteries for watts of PV has been proposed for other storage). CSP plants with thermal storage large-scale projects across the country.121 can deliver electricity even when the sun is not shining, enabling them to compete directly with “base load” sources of power Solar Power in a Smart Grid such as coal and nuclear power, thereby The nation’s electricity system was de- expanding the share of electricity demand signed as a one-way street—a small num- that can be satisfied by solar power. ber of large, central power plants gener- Ultimately, the nation will need to take ate electricity, which is then delivered to

A Solar Future for America 33 millions of homes and businesses. To keep to integrate solar energy into the existing the grid running reliably, generators must grid.122 But maximizing the share of our be turned off and on to ensure a perfect electricity that comes from solar power balance between the supply and demand will likely require changes in the way we at every second of the day. produce and deliver electricity—as well The spread of solar photovoltaic power, as investments in a well-designed “smart however, will make the job of keeping the grid.” With creativity and investment, grid in balance more complicated. Instead experts suggest that as much as 20 to 30 of homes and businesses being electricity percent of our electricity could someday consumers, many will also be electricity come from photovoltaics—greatly producers, feeding power into the grid. In expanding the ability of solar energy to addition, solar energy is variable in ways address the nation’s energy needs.123 that are both predictable (night versus A well-designed “smart grid” is one day) and unpredictable (the passing of a that is much more sophisticated in manag- stray cloud). ing electricity supply and demand than the America has a long way to go before current grid. It might include: solar energy begins to have a meaningful impact on the grid. The nation can • Smart inverters—Technology to en- dramatically expand the amount of solar able utilities to control the flow of power in today’s grid without reliability power from solar PV inverters—the problems, and an even greater fraction can devices that transform DC power be provided if thoughtful steps are taken from solar panels to the AC power

Plug-in vehicles, such as these plug-in hybrids, can contribute to stabilizing the grid by providing electricity storage capacity. Energy storage is a key technology that can enable renewable sources of energy such as solar energy to play a larger role in America’s energy future. Credit: Argonne National Laboratory

34 Building a Solar Future used in the grid and in homes. Utili- batteries to provide quick backup ties could use these “smart inverters” power during cloud passages and to to manage the flow of solar electricity store excess solar power produced into the grid to maximize grid stability. during peak periods. There are many possible ways to incorporate energy • Smart controls—Homeowners could storage into the grid, including the use smart controls to make the maxi- installation of batteries at various mum use of solar electricity—for ex- points in the grid and the use of bat- ample, by heating hot water, running teries in plug-in vehicles.124 space heating or cooling equipment, or (someday) charging plug-in ve- These investments in smart grid tech- hicles at times when solar panels are nologies have the potential to deliver large producing the maximum amount of returns. A recent study by Navigant Con- electricity instead of, for example, the sulting found that investment in a “PV evening hours when solar panels do Smart Grid” would deliver positive eco- not produce electricity but demand nomic benefits, while improving the eco- for power remains high. nomics of investments in PV and dramatically increasing the amount of solar power • Smart energy storage, including the that can be integrated into the grid.125 installation and remote control of

A Solar Future for America 35 Mapping Out a Solar Vision

merica’s potential for solar energy Distributed solar PV – A 2004 study development is virtually limitless. by Navigant Consulting estimated the ASolar energy can meet a wide variety technical capacity for PV on residential of energy needs, it is available everywhere and commercial rooftops in 2010 at 712 in the United States, and the prices of key gigawatts—roughly enough to supply solar technologies are declining—in some about a quarter of America’s electricity us- cases, rapidly. ing current photovoltaic technologies.127 The nation should set a course to Rooftops, however, aren’t the only places maximize our use of solar energy, putting where solar panels can be installed. Fac- America on a path toward an energy sys- tory roofs, roadsides, parking lots, former tem that relies primarily on clean, renew- industrial sites, airport buffer lands, waste- able sources of energy. A good place to water treatment plants and other built-up start would be to ensure that at least 10 areas could also play host to solar PV. percent of all the energy used in America Moreover, PV could be used “off the grid” in 2030—and preferably more—comes to offset energy demand, as has increas- from the sun. (See “Energy vs. Electricity: ingly been the case in recent years with What Does the 10 Percent Target Mean?” the advent of solar powered streetlights, page 38.) emergency call boxes, water pumps, etc.

Utility-scale solar—The American Southwest and other sunny areas of the country have almost endless potential to produce solar energy. Analysis by the National Renewable Energy Laboratory America’s Solar Potential (NREL) has found that prime locations The nation’s potential for solar energy in the Southwest—those in proximity to dwarfs our current consumption of ener- transmission lines, on flat topography, and gy, as well as projected energy use in the outside of environmentally sensitive ar- future. eas—could host 11,000 gigawatts of con-

36 Building a Solar Future Figure 3. U.S. Photovoltaic Resource Map

America’s solar resource compares favorably with the resource in two leading countries for solar energy development: Germany and Spain. Even the least sunny areas of the contiguous U.S. have solar resources on a par with Germany, while much of the southwestern U.S. has a better solar resource than Spain. Credit: National Renewable Energy Laboratory

centrating solar power plants, enough to earlier, the International Energy Agency produce six times more electricity than the estimates that industrial solar process heat entire nation consumes today.128 could displace 4 percent of industrial heat demand—reducing America’s energy con- Solar water heating—Solar water sumption by at least another 0.15 percent. heating presents the potential for great Passive solar and active solar heat- energy savings. A national analysis of ing, cooling and lighting—America’s technical potential by NREL estimated potential for passive solar energy—and for that the nation could avoid 0.5 quadril- the development of “active” solar heat- lion Btu of fossil fuel consumption (about ing, cooling and lighting technologies—is 0.5 percent of America’s current energy difficult to quantify, but the technology use), along with the consumption of large clearly exists to build homes and commer- amounts of electricity, through wholesale cial buildings that use dramatically less en- adoption of solar water heating. As noted ergy than conventional buildings.

Mapping Out a Solar Vision 37 Energy vs. Electricity: What Does the 10 Percent Target Mean?

any targets for renewable energy development are set in terms of the percent- Mage of our electricity supply that comes from renewable sources of power. State renewable electricity standards (RES) typically take this approach, with solar “carve outs” in RES policies sometimes setting goals for a percentage of electricity that will come from solar photovoltaics and/or concentrating solar power. About 40 percent of America’s total energy consumption is devoted to the generation of electricity.126 But, as this report shows, solar energy can do much more than generate electricity—it can be used to improve the energy efficiency of our buildings and to substitute directly for fossil fuels such as natural gas and oil. The target proposed in this report—getting 10 percent of America’s total energy from the sun—is, therefore, broader and more ambitious than a target of obtaining 10, or even 20 percent of our electricity from solar power. While shifting a large share of our electricity production to solar power is an important component of maximizing America’s solar energy potential, the nation must also take full advantage of the potential for solar energy to offset fossil fuel use through passive solar heating and lighting and to replace fossil fuels in our homes and businesses, as well as our transportation system. The target proposed in this report recognizes the broad range of ways that solar energy can power our economy and sets an ambitious goal for its future development.

A Near-Term Goal us on the road to an America that is free America’s solar potential is nearly limit- from dependence on fossil fuels and the less. But tapping that potential—and do- environmental damage those fuels cause. ing it on a timeline that will make a mean- A goal of obtaining 10 percent of ingful contribution to addressing global America’s energy from the sun by 2030 is warming and fossil fuel dependence—will just such a challenging target. We already require a bold national commitment to have the technology to get most of the rebuild our energy system around clean, way there. But achieving that goal would renewable energy. also challenge the nation to develop new The project of rebuilding our energy technologies, and to begin to undertake system will take time. Our existing systems the type of systemic changes that will en- for extracting, processing and delivering able solar energy to play an even bigger energy from fossil fuels are more than a role in decades to come. century in the making and the result of Achieving a 10 percent goal for solar untold billions of dollars in investment. energy would result, in two decades’ time, However, it is imperative that we begin in the sun providing us with more ener- the job of rebuilding our economy around gy than we currently produce at nuclear renewable energy now, and commit to power plants, more than half as much challenging short-term goals that will put as we currently consume in our cars and

38 Building a Solar Future light trucks, or nearly half as much as we Under that scenario, obtaining 10 per- currently obtain from burning coal. To- cent of our energy from the sun would gether with efforts to improve energy ef- require the nation to offset roughly 8.8 ficiency and develop other renewable en- quads of energy consumption. Much of ergy sources, solar energy can play a major this energy can come from solar electricity role in weaning the nation from polluting, generation—both photovoltaic and con- dangerous, unstable and, in some cases, centrating solar power. As noted above, increasingly expensive forms of energy. the nation has enough solar energy poten- The first step to getting a large share of tial to power our entire economy several our nation’s energy from solar energy is to times over. A scenario in which the nation reduce our use of energy overall through obtains 20 percent of its projected electric- improved energy efficiency. A recent draft ity use in 2030 from solar energy (taking report by the National Academy of Sci- into account the energy savings resulting ences (NAS) found that the nation could from the efficiency improvements in the cost-effectively reduce its overall ener- NAS study) would offset approximately gy consumption by 26 to 31 percent by 6.4 quads of primary energy use at elec- 2030.129 The NAS report includes some, tric power plants.131 (A team of researchers but not all, passive solar technologies, as led by experts at the National Renewable well as the introduction of plug-in hybrid Energy Laboratory is exploring the poten- vehicles, and estimates that, by taking full tial and implications of a 20 percent solar advantage of the nation’s energy efficien- electricity scenario as this report goes to cy potential, energy consumption could press.) be reduced to 82 to 88 quadrillion Btus The remaining 2.4 quads could come (quads) by 2030, compared to a projected from a variety of other sources. Taking ad- 118 quads.130 vantage of the half the nation’s potential

America has tremendous potential to capture energy from the sunlight that strikes rooftops and paved areas, such as this parking lot in San Diego. Credit: Envision Solar

Mapping Out a Solar Vision 39 for solar water heating on homes and com- • Installation of solar district heating mercial buildings could reduce America’s and active solar space heating and projected primary energy consumption in cooling systems. 2030 by a minimum of 0.3 quads. Tapping the potential for solar process heat in in- • Deployment of distributed solar dustry would provide additional savings. energy systems in agriculture, for Other measures that could increase the vehicle charging, and other share of our nation’s energy that comes applications. from the sun include: Getting 10 percent of our energy from • Widespread deployment of technolo- the sun will not be easy. It will take a gies to further reduce energy con- dedicated and concerted effort starting sumption beyond the levels discussed now, as well as great creativity in develop- in the NAS study, including wide- ing public policies that can surmount the spread adoption of net zero-energy barriers to the rapid deployment of solar buildings and shifting of vehicle and energy and ensure that the transition to a airline trips to highly efficient modes clean energy system happens both quickly such as public transportation and rail. and smoothly. If America can muster the creativity and will to achieve that goal, • Increased use of solar electricity however, the benefits for the nation’s en- generation, possibly through the vironment, energy security and well-being development of energy storage. would be dramatic.

40 Building a Solar Future Achieving a Solar America

olar energy has a great deal going for consumption, including air pollution, it. It is enormously popular—polls global warming and national security im- Sconsistently find that the vast major- plications, are not factored in. ity of Americans back increased govern- But cost is actually one of the less-im- ment support for solar energy, and that portant barriers to solar energy. There are Americans prefer expansion of renew- a host of regulatory, legal, information and able energy technologies, including solar, financing barriers—sometimes erected by over other approaches to addressing the nation’s energy challenges.132 Solar energy is available everywhere, can be used for many purposes, and the fuel is free. But despite these advantages, achieving a solar future for America won’t happen on its own.

Understanding the Barriers to a Solar America Conventional wisdom holds that solar energy hasn’t made serious inroads in the United States because it is too expensive. And to a certain extent that is true: “active” solar energy systems such as photovoltaics and solar water heating systems Solar energy can power communities across the nation, even in northern cli- have historically been more expensive mates. The Drake Landing solar community in Okotoks, Alberta, Canada, just south of Calgary, relies on the sun for 90 percent of its space heating than conventional sources of energy—es- needs through the use of a solar district heating system with seasonal storage. pecially when the social costs of fossil fuel Credit: Natural Resources Canada

Achieving a Solar America 41 companies with an interest in preserving benefits of passive solar techniques the status quo—that prevent solar energy or how to implement them in con- from gaining more traction in the United struction. Consumers or businesses States. These are barriers that can be sur- may be unaware of how to go about mounted by creative public policy. integrating solar energy into their The current cost barriers to solar en- buildings, or of how much energy ergy are falling, in some cases rapidly. Be- and money solar technologies can tween 1998 and 2008, the installed cost of save. All of these knowledge barri- photovoltaic systems declined by 31 per- ers hamper the deployment of solar cent, excluding the impacts of tax incen- energy. tives and subsidies.133 During 2009, prices declined even further, with the cost of PV • Regulatory barriers: In some places, modules falling by roughly 20 percent.134 installing solar panels on one’s roof The cost of concentrating solar power has or in one’s yard isn’t just a challenge; declined as well, from about 44 cents per it’s against the law. Restrictive hom- kilowatt-hour for the first plant built in eowners’ association rules may pre- the 1980s to roughly 15 to 16 cents per vent the installation of solar energy, kilowatt-hour today, and costs can be ex- or archaic zoning rules may limit pected to continue falling.135 homeowners’ ability to install solar By 2015, the cost of retrofitting a home energy facilities on their properties. with solar panels is projected to drop to $4.80 per Watt (from $7.40 per Watt in • Upfront costs: One common 2007) and could fall to as low as $3.10 per reason that people do not invest in Watt in that year if researchers meet the clean energy or energy efficiency targets established by the Department of technologies is that the costs occur Energy’s Solar America Initiative.136 immediately, while the benefits occur At those prices, solar photovoltaics will over the entire life of the system. In achieve “grid parity”—a price equivalent essence, buying a solar energy col- with the lifetime cost of an equivalent lector is like buying several decades amount of grid electricity—by the middle of energy all at one time. Even if the of this decade. (Indeed, in some states with overall cost is lower, it can be difficult high electricity prices and generous incen- for many families and businesses to tives for solar power, such as California, spend so much at once. grid parity has already arrived.)137 If the price of solar energy becomes • Capital availability: A related obsta- lower than that of conventional sources, cle is the fact that some homeowners one would think that the path would be or businesses that wish to install solar clear for solar energy to take on a leading energy systems may not be able to role in America’s energy picture. Unfortu- obtain the credit necessary to finance nately, it’s not that simple. the installation. Banks, especially Solar energy faces a set of additional ob- given the recent credit crunch, may stacles that must be overcome if America be unwilling to lend to homeowners is to achieve the benefits of a solar future: to finance the installation of a solar energy system. As a result, lower- • Knowledge barriers: The most income households, those with poor basic obstacle to the spread of solar credit, and many small businesses technologies is lack of knowledge. miss out on the opportunity to install Builders may not understand the solar energy.

42 Building a Solar Future • Payback times: A solar energy sys- Government and utility financial tem may pay for itself over time, but incentives can compensate for the individuals and particularly business- failure to take into account the true es will be reluctant to invest in solar costs and benefits of various energy if the payback period is too long. technologies. Economic research suggests that only a small percentage of customers will • Risk: When consumers draw power use a technology that takes five or from the electric grid, they are shel- more years to pay back its costs.138 tered from the financial risks posed For businesses, required payback by the failure of electric generating times can be even shorter—a review equipment. Even if ratepayers must of cancelled industrial solar process pay to replace a failed power plant, heat projects found that many com- the costs of doing so are spread panies required payback periods of among thousands or millions of three years or less for capital invest- customers. Owners of solar energy ments—a standard that the proposed systems, however, bear the risk that projects barely failed to meet.139 the system will fail or be destroyed and need to be replaced (though • Length of tenure: Even homeown- these risks can be mitigated through ers or businesses that are willing to warranties and insurance). accept longer payback times may be unwilling to invest in solar due to • Utility barriers: Traditionally regu- concerns that they will move out of lated utilities, which are assured a their current location before the solar return on investment for the invest- system pays itself off, or that the re- ments they make in electricity gen- maining value of the system will not eration and often benefit financially be received upon resale. by selling more power to consumers, have financial incentives to resist • Split incentives: When the owner the spread of customer-owned solar of a building is different from the systems that reduce the demand for person who pays the utility bills, the grid-supplied electricity. Utilities owner has less incentive to install a may create hassles for consumers or solar energy system. Unless they can businesses seeking to connect their be confident that they will receive the solar energy systems to the elec- benefits of their purchase, landlords tric grid, or establish limits on the will have little reason to consider number or size of systems eligible for solar technologies. net metering, in which consumers are compensated for the energy they • Failure to incorporate social supply to the grid. Utilities seeking benefits: Owners of solar panels to build their own solar projects may rarely receive checks in the mail run into barriers of a different sort: for the benefits their investments lack of access to the transmission deliver to society—reduced global capacity needed to carry their power warming impacts, reduced health to customers. care costs due to avoided pollution, enhanced national security, reduced It is these hurdles, more than cost, that need to invest in peaking electric often impede the spread of solar power. plants and transmission wires, etc. After all, Americans have a strong recent

Achieving a Solar America 43 track record of embracing exciting new Policies to Build a Solar green technologies—even those with higher upfront costs and uncertain pay- America back. The experience with hybrid-electric The first step in achieving a solar vision for vehicles—of which more than 1 million America is to take the many creative pub- have been sold in the United States over lic policy tools that are already promoting the past decade—demonstrates the appeal the adoption of solar energy at the local, of energy-saving technologies.140 Now, state and federal levels and implement thanks to early consumer demand, car them more broadly. The nation must also manufacturers produce hybrids in a variety lay the groundwork for future large-scale of styles and produce more of them, cut- adoption of solar energy in the decades to ting the price differential between hybrids come. and conventional vehicles. This dynamic Many public policies are making a real will enable hybrids to make even bigger difference in speeding the diffusion of so- inroads into the auto marketplace in the lar power. In California, for example, pro- years ahead. grams under the banner of the California The big difference between solar energy Solar Initiative have resulted in the instal- and hybrid vehicles is that switching from lation of 283 megawatts of solar PV since a conventional car to a hybrid is relatively the beginning of 2007, more than dou- easy. Hybrids are sold at the same dealer- bling the amount of solar power installed ships as traditional cars, are financed in in the state in less than three years.141 New the same way, use the same roads and can Jersey has achieved similar results, install- be parked in the same driveways. Adopt- ing more than 60 megawatts of solar PV in ing solar energy, on the other hand, is 2008 and 2009.142 “disruptive”—it challenges our traditional Among the many public policies that relationship with energy. Homeowners can contribute to the spread of solar en- transform from energy consumers to energy are the following: ergy producers; businesses and homeowners make long-term investments in clean energy rather than buying electricity by Spurring Demand through the kilowatt-hour over time; and the elec- Financial Incentives tric grid becomes a two-way rather than Financial incentives for solar power have one-way street. several public policy purposes. First, they Getting solar energy into America’s serve as a means for compensating consum- homes and businesses isn’t just about makers for the societal benefits of solar power. ing solar energy cheaper, though that will They also help to create a robust early help. It is about adapting our current ways market for solar technologies—a market of managing, delivering and financing en- strong enough to persuade companies to ergy to unlock the potential for solar en- invest in the research, development and ergy that is already at our doorstep. expanded manufacturing capacity needed By using public policy to remove the to hasten the day when solar power will “emergency brakes” that inhibit the de- achieve cost parity with fossil fuels. More- ployment of solar energy and finding ways over, financial incentives for solar energy to step on the accelerator, America can can balance the impact of the massive fed- make solar energy systems as common— eral subsidies currently received by fossil or more common—on America’s homes fuel producers. Between 2002 and 2008, and businesses ten years from now than for example, the federal government lav- hybrid cars are on the road today. ished $72 billion in subsidies on the fossil

44 Building a Solar Future fuel industry, compared with just $29 billion to renewable energy (with most of the renewable energy funds used to subsidize corn ethanol).143 California, New Jersey and other states have helped spur solar power installations through financial incentives. Financial incentives can come in several forms:

Cash incentives provide an upfront rebate to homeowners or businesses installing solar panels. California’s Million So- Fair net metering policies can ensure that consumers lar Roofs Initiative, for example, provides receive the full benefits of their investments in solar grants to homeowners who install solar energy. Credit: Kenn Kiser systems, with the amount of the rebate declining over time to reflect the anticipated declining cost of solar power. There are Vermont law, for example, is designed to various types of cash incentives including ensure that homeowners or businesses rebates paid upfront or over time, grants, receive the same return on equity for or access to a renewable energy credit their investment in solar as utilities would market. receive for their investments in power generation technology.146 Tax credits also encourage individuals and businesses to install solar energy. Net metering policies enable consum- Current federal law allows individuals to ers to receive fair compensation for the receive a tax credit for 30 percent of the excess solar electricity they feed into the cost of installing a qualified solar PV or grid. Net metering typically compensates hot water system.144 The federal govern- consumers at the retail or wholesale price ment also provides a similar investment of electricity rather than at an incentiv- tax credit for businesses adopting solar en- ized price. Not all net metering policies ergy.145 As with cash incentives, the value are created equal, however—some poli- of tax credits can be made to decline over cies require consumers to forfeit accumu- time as solar energy becomes increasingly lated credits on their electricity bills to the cost-effective. utilities at the end of the year, while other utilities and states set onerous limits on Feed-in tariffs are special rates paid the size of solar energy systems that are to owners of solar photovoltaic systems eligible for net metering or on the share of that supply electricity to the grid. The a utility’s overall electricity eligible for net idea behind a feed-in tariff is to reduce metering. Consistent, fair and generous the financial uncertainty facing would- net metering policies can make it much be installers of solar panels by providing more advantageous for homeowners and a long-term, guaranteed, incentivized businesses to install solar energy systems. rate for power supplied by a solar energy system to the grid. Feed-in tariffs have played a large role in the development Leveling the Playing Field of Germany’s world-leading solar power for Solar industry, and have recently been adopted Solar energy provides a vast array of benefits by Vermont and Washington state. The to electricity consumers, the environment,

Policies to Build a Solar America 45 and society at large. Public policies can as New Jersey enable individuals or busi- ensure that solar energy is treated fairly in nesses who install solar energy systems to the marketplace. receive payments from utilities seeking to meet their renewable energy obligations, Policies to encourage utility deploy- providing yet another financial incentive ment of distributed solar energy can be for the adoption of solar power. designed to ensure that the unique value of solar energy is taken into account when Government purchasing require- utilities decide which energy resources to ments are similar to RESs in that they re- use. For example, California includes a quire government agencies to “lead by ex- “time-of-delivery adder” in assessing the ample” by getting a share of their energy value of projects proposed for compli- from solar and other forms of renewable ance with the state’s renewable electricity energy. For example, federal law requires standard, ensuring that the added value of the U.S. government to get at least 7.5 electricity delivered during periods of peak percent of its electricity from renewable demand is factored into decision-making. power by 2013, dramatically reduce fossil The value of distributed solar energy in fuel use in government facilities, and de- avoiding transmission line expenses and ploy solar water heating equipment if it is other benefits of solar could also be taken cost effective over the entire life cycle of into account. the equipment.147

Putting a price on global warming pollution can ensure that decision-makers Overcoming Financing Barriers consider the environmental costs and ben- Local state and federal governments are efits of the energy choices they make. A developing novel public policy tools to cap-and-trade system for global warming surmount barriers to the financing of solar pollution, such as the one that has already energy projects. Among them: passed the U.S. House of Representatives, would begin to incorporate the real cost Municipal financing—Eighteen states of pollution from fossil fuel power plants now allow municipalities to finance indi- into the price of energy, and would help viduals’ solar energy installations, recoup- promote the development of clean energy ing the costs through a special assessment alternatives. on the property owner’s tax bill.148 This model—called property-assessed clean energy (PACE) financing—enables mu- Ramping Up Solar with nicipalities to use their ability to obtain Renewable Electricity Standards financing at low interest rates to pay for Renewable electricity standards (RES) the upfront cost of installing solar panels are requirements that utilities in a given on homes and businesses. Property own- state obtain a certain percentage of their ers then pay back the costs over a period electricity from renewable sources of en- of 20 years on their property tax bills. If ergy. Fourteen states have established so- a property owner sells the property dur- lar carve-outs in their standards to ensure ing that period, the charge to pay back that the RES encourages the development the solar panel remains on the property of solar energy. RESs encourage utilities tax bill for the new owner. The PACE to build large-scale solar projects and to system overcomes several barriers to the install distributed solar systems on homes deployment of solar power: it absolves ho- and businesses. In addition, states such meowners of the risk that they will move

46 Building a Solar Future out before they receive the full benefits power installations not located on their of the system, it provides low-interest fi- properties. This type of community solar nancing, and it enables homeowners to program enables consumers who are begin seeing the benefits of their invest- unable to install solar energy on their own ment right away through lower utility properties to participate in expanding the bills. A similar model, called utility on-bill reach of clean energy. While promising financing, offers home or business owners and capable of filling a unique niche for the opportunity to pay for their solar en- those who can’t go solar themselves, this ergy purchase through a small charge in program should not take the place of their utility bill—the same place that they opportunities for customers to own their will see savings from decreased reliance on own solar systems. fossil fuels. Low-interest loans and loan guar- Community solar—As noted earlier, antees reduce the pay-back time for solar at least one electric cooperative has energy installations. A PV array that will experimented with the idea of allowing take 20 years to pay for itself can become customers to purchase a solar panel immediately profitable if a homeowner located on utility land, with the value of can pay for it through a low-interest loan. the energy produced by the panel credited The U.S. Department of Agriculture, to the consumer on his or her bill. Several for example, operates a loan guarantee states are considering expanding this program for agricultural adoption of re- model to allow groups of homeowners newable energy technologies. Similarly, to finance and reap the benefits of solar federal renewable energy bonds enable

Government can help spur the development of a solar economy by taking the lead in installing solar energy systems on public buildings, such as this middle school in Missouri. Credit: Missouri Department of Natural Resources

Policies to Build a Solar America 47 local and state government agencies to fi- all new homes are designed to accommo- nance solar projects at very low interest date solar electricity or hot water. These rates.149 policies make it easier and less expensive for homeowners to implement solar energy when it suits them. New Mexico, for Implementing Advanced Building example, adopted legislation in 2007 Codes and Standards authorizing new construction standards New buildings present the greatest op- that require the proper strength and ori- portunity to integrate solar energy in a entation of roofs, wiring, and other pro- cost-effective way while combining it with visions to allow the future integration of 150 energy efficiency—a natural marriage. solar energy. Similar policies could re- Building codes can be designed to encour- quire homebuilders to offer solar as a stan- age the use of solar energy technologies in dard option on new homes, just as they do a variety of ways. choices of paint color or countertops.

Advanced building energy codes re- Solar requirements—One way to en- quire a dramatic increase in the energy courage the deployment of solar energy on efficiency of new residential and commer- new buildings is simply to require it. Such a cial buildings. Ambitious building energy policy may seem extreme at first blush, but codes can play a particularly important solar mandates are becoming increasingly role in encouraging the use of passive solar common worldwide and are beginning to design techniques in new buildings, and gain a foothold in the United States. Israel in ensuring that designers take a “whole has required the use of solar water heaters building” approach to integrating renew- since 1957 and Spain recently adopted a 151 able energy technologies with energy ef- similar policy. As of January 2010, Ha- ficiency to produce a new generation of waii, where approximately one-quarter of buildings that is far less dependent on fossil all homes already have solar water heaters, fuels. The ultimate goal is to design zero will require the use of solar water heating net energy buildings, which produce as in all new residential construction, with a 152 much energy as they use over the course few exceptions. of a year. Local and state governments can create incentive programs for the development of zero net energy buildings and Guaranteeing Access to commit to ratcheting up building energy Solar Energy codes over time to achieve that goal. Restrictive and outdated rules by homeowners’ associations, local governments Similarly, government green building and utilities can prevent willing home- requirements can ensure that new public owners and businesses from adopting solar buildings, including schools and govern- energy. Solar access laws guarantee indi- ment offices, achieve maximum levels of viduals the ability to develop solar energy energy efficiency and incorporate solar on their properties, in part by establishing energy technologies. These requirements the ground rules regarding individuals’ ac- assure that government buildings go be- cess to sunlight (i.e., what happens when a yond the baseline requirements of build- tree or neighboring structure blocks a so- ing energy codes to deliver exceptional lar panel), and in part by limiting the abil- energy-saving performance. ity of homeowners’ associations and local governments to restrict the installation of Solar-ready home policies require that solar energy systems.

48 Building a Solar Future Solar energy installations can also run State and federal governments should cre- into permitting bottlenecks at the mu- ate and expand job training programs for nicipal level. Permitting reforms include solar workers and should work with pro- reducing or eliminating permitting fees, fessional organizations and government reducing the length of time necessary for research and development agencies to obtaining permits for solar installations, ensure that the latest knowledge about the and standardizing permitting require- most effective ways to harness solar ener- ments between jurisdictions, as well as en- gy is quickly disseminated to practitioners suring a well-trained and adequate num- in the field. ber of city level inspectors and permitting officials. Governments should also develop creative policies to encourage domestic Utility policies can also erect hurdles manufacturing of solar energy equip- to solar development by allowing utilities ment. As the United States builds up a to charge excessive “standby fees” for so- substantial domestic market for solar en- lar hookups, capping the amount of solar ergy, the nation should use that develop- energy eligible for net metering or, in the ment to take leadership in the global solar most extreme cases, not offering net me- energy market. Well-designed tax credits tering at all. Fair net metering policies and other policies can ensure that a greater allow for surplus solar power compensa- share of the clean energy jobs created by a tion where a solar system owner gets paid large expansion of solar energy remains in for surplus solar electricity generated over the United States. a year-long period, allow a wide range of solar projects to qualify for net metering, Consumers need far better tools to as- and eliminate unjustified restrictive caps certain the energy efficiency of buildings on the percentage of load that can be met and building designs. A consumer shop- with solar energy systems under net me- ping for a new clothes washer, for exam- tering. States without any net metering ple, can read the government-required policies should also establish them. EnergyGuide label to quickly determine the energy cost of that appliance over its expected lifetime compared with other Educating the Public and Training models. Building energy labeling re- a Solar Workforce quirements would require a home energy Knowledge barriers are among the most audit to be conducted prior to sale to allow fundamental impediments to the acceler- the purchaser of the building to determine ated deployment of solar energy. Consum- its level of energy efficiency. Building en- ers need the tools to evaluate whether so- ergy labeling would increase the likeli- lar energy makes sense for them and good hood that individuals would recapture the roadmaps for how to make the process of value of their investments in passive solar “going solar” as easy as possible. Build- technologies and solar panels on resale by ers, architects, electricians, plumbers and ensuring that would-be purchasers under- other professionals need to understand the stand the monetary savings that will result potential benefits of solar energy and how from those investments. to integrate it into their work. Public education programs can help Workforce training is critical to en- the public to understand the benefits of suring that America has the base of trained solar energy and provide easy ways (such workers necessary to build a solar future. as 1-800 numbers or directions to a Web

Policies to Build a Solar America 49 site) for consumers to start the process to connect areas with strong solar energy of “going solar.” These programs should potential to places where electricity is include targeted outreach to groups with used. It is important, however, that the specific information needs. Industrial plant nation not overbuild transmission capac- managers in particular, who can potentially ity and insist that new transmission lines install some of the largest and most cost are devoted to carrying renewable energy, effective solar energy systems, are likely to not paving the way for additional fossil avoid unfamiliar technologies when pro- fuel-fired plants. New transmission lines viding for critical energy needs.153 Educa- should be run, wherever possible, along tion efforts that familiarize these decision existing corridors, and should always be makers with the range of available solar carefully sited to minimize environmental options, and how those technologies can impacts. serve their needs, can lead to more use of solar energy for appropriate and beneficial Discovering New Solutions purposes. Many solar energy technologies are ready to make an immediate contribution to the Building the Solar Grid nation’s energy challenges. Solar photo- As noted earlier, investments in a smart voltaics, residential and commercial solar grid are critical to unlock the full poten- water heating systems, and concentrating tial of distributed solar electricity. Invest- solar power plants are all proven technol- ing the necessary resources in smart grid ogies. Research and development pro- development is important, but definitions grams can continue to hone and improve of “smart grid” vary and the nation can those technologies, increasing the ef- ill-afford to waste resources on technolo- ficiency of solar cells, helping to develop gies that are unnecessary or that do not efficient new manufacturing techniques, move the nation toward a clean energy and finding new ways to overcome bar- future. Smart grid investments should be riers to the integration of large amounts channeled toward those technologies that of solar energy into our economy. can contribute to the expansion of solar There are, however, several solar tech- power, including advanced inverters, im- nologies that, while promising, require proved communications, and deployment greater effort to develop. Technologies of electricity storage. such as industrial solar process heat, solar district heating, active solar lighting, and Similarly, efforts to build a smarter grid solar cooling have the potential to deliver should be undertaken alongside clean en- great benefits in energy savings and pol- ergy development efforts in other fields, lution reductions. These technologies specifically the development and deploy- would benefit from concerted and coor- ment of plug-in vehicles. Should plug-in dinated research efforts and development vehicles prove to be a grid asset—as the strategies. potential for short-term energy storage in Looking far down the road, research- vehicle batteries suggests they may—poli- ers will also need to develop methods cies should be put in place to ensure that for recycling solar energy systems that plug-in vehicle owners receive fair com- have reached the end of their useful lives, pensation for the services they provide to reclaiming as many useful materials as the grid. possible and ensuring that solar systems are disposed of without harm to the envi- Finally, the nation should ensure that ronment. adequate transmission capacity exists Finally, as this paper shows, there are

50 Building a Solar Future nearly as many potential ways to take funded by the agency is exploring the po- advantage of solar energy as the human tential to use living organisms to convert mind can imagine. Not all of these ways sunlight and carbon dioxide into trans- will turn out to be practical, but any idea portation fuel.154 Many—indeed, most— with a chance of making a meaning- of the ideas studied by ARPA-E will never ful contribution should be explored. In come to fruition. But redoubling Ameri- 2009, the U.S. provided funding for the ca’s commitment to basic energy research Advanced Research Projects Agency-En- will not only increase the chances of ergy (ARPA-E)—an agency specifically discovering the next transformative solar designed to explore experimental energy energy technology, but will also increase technologies with transformative poten- the chances that that technology will be tial. For example, one research project developed in the United States.

Policies to Build a Solar America 51 Notes

1 U.S. Department of Energy, Energy 5 River Network, Understanding the Information Administration, Annual En- Clean Water Act: Poor Mining Practices and ergy Outlook 2009: An Updated Reference Abandoned Mines, downloaded from www. Case, April 2009. rivernetwork.org/rn/poor-mining-prac- 2 2006 gross domestic product equaled tices, 31 December 2009. $13,178.4 billion in 2007 dollars. From 6 U.S. Global Change Research Pro- U.S. Bureau of Economic Analysis, Cur- gram, Global Climate Change Impacts in rent-Dollar and “Real” Gross Domestic the United States, Cambridge University Product, 29 April 2009. The United States Press, 2009. spent $921.2 billion in 2007 dollars on 7 Michael Roddy, “Climate Change fossil fuels in 2006. U.S. consumption Turning Seas Acid: Scientists,” Reuters, data from U.S. Department of Energy, 31 May 2009; David Adam, “How Global Energy Information Administration, State Warming Sealed the Fate of the World’s Energy Data System, Consumption, British Coral Reefs,” The Guardian, 2 September Thermal Units, 1960-2006, 28 November 2009. 2008. U.S. price data from U.S. Dep- partment of Energy, Energy Information 8 United Nations Environment Pro- Administration, Annual Energy Outlook: gramme, Impacts of Climate Change Com- Low-Price Case, Table 3. Energy Prices by ing Faster and Sooner: New Science Report Sector and Source, March 2009. Underlines Urgency for Governments to Seal the Deal in Copenhagen (press release), 24 3 U.S. Bureau of Labor Statistics, Con- September 2009; United Nations Envi- sumer Expenditure Survey, 2007: Table 2. ronment Programme, Climate Change Sci- Income Before Taxes: Average Annual Ex- ence Compendium 2009, September 2009. penditures and Characteristics, 28 Novem- ber 2008. 9 Ibid. 4 American Lung Association, State of 10 Temperature: A.P. Sokolov, et al., the Air 2009, 2009. Massachusetts Institute of Technology, Joint Program on the Science and Policy

52 Building a Solar Future of Global Change, “Probabilistic Forecast High Surface Temperatures?” Geophysical for 21st Century Climate Based on Un- Research Letters 35, L14703 (doi:10.1029/ certainties in Emissions (without Policy) 2008GL034071), 19 July 2008. Amazon: and Climate Parameters,” Journal of Cli- Rachel Warren, “Impacts of Global Cli- mate 22 (19): 5175-5204, October 2009 mate Change at Different Annual Mean (doi: 10.1175/2009JCLI2863.1); Vicky Global Temperature Increases,” in Hans Pope, United Kingdom Met Office, Head Joachim Schnellnhuber, ed., Avoiding of Climate Change Advice, “Met Office Dangerous Climate Change, Cambridge Warn of ‘Catastrophic’ Rise in Tempera- University Press, 2006; HM Treasury, ture,” The Times Online (London), 19 De- Stern Review: The Economics of Climate cember 2008. 6.5 feet: W.T. Pfeffer, et al., Change, 2006, 57. Institute of Arctic and Alpine Research, 12 U.S. Department of Energy, Energy University of Colorado, Boulder, “Kine- Information Administration, Emissions of matic Constraints on Glacier Contribu- Greenhouse Gases in the United States 2008, tions to 21st-Century Sea-Level Rise,” December 2009. Science 321: 1340-1343, September 2008. 13 Vasilis M. Fthenakis, Hyung Chul 11 Extinction: Intergovernmental Panel Kim and Erik Alsema, “Emissions from on Climate Change, Fourth Assessment Photovoltaic Life Cycles,” Environmental Report, Climate Change 2007: Synthesis Science and Technology, 42(6): 2168-2174, Report, 2007; Brian Walsh, “The New 2008. Age of Extinction,” Time, 1 April 2009. Drought: One third: E.J. Burke, S.J. 14 U.S. Department of Energy, Office Brown, and N. Christidis, “Modeling the of Energy Efficiency and Renewable En- Recent Evolution of Global Drought and ergy, PV FAQs: What Is the Energy Payback Projections for the Twenty-First Century for PV?, January 2004. with the Hadley Centre Climate Model,” 15 Greenpeace International, European Journal of Hydrometeorology 7: 1113–1125, Solar Thermal Industry Association and 2006; Susan Solomon, et al., U.S. Na- IEA SolarPACES, Concentrated Solar tional Oceanic and Atmospheric Admin- Thermal Power—Now!, September 2005. istration, “Irreversible Climate Change 16 U.S. Department of Energy, Of- Due to Carbon Emissions,” Proceedings fice of Energy Efficiency and Renewable of the National Academy of Sciences 106: Energy, Solar Energy Technologies Pro- 1704-1709, 10 February 2009. Wildfires: gram, PV in Simple, Stand Alone Systems, 5 Donald McKenzie, et al., U.S. Depart- January 2006. ment of Agriculture, “Climatic Change, Wildfire, and Conservation,”Conserva - 17 U.S. Department of Energy, Of- tion Biology 18(4): 890-902, August 2004. fice of Energy Efficiency and Renew- Hurricanes: Researchers at Florida State able Energy, Solar Energy Technologies University calculate that for every 1° C Program, Why PV Is Important, 5 January increase in sea-surface temperatures, the 2006. frequency of severe hurricanes (category 18 European Photovoltaic Industry 4 and 5) increases by nearly one-third. Association, Global Market Outlook for James Elsner, et al., “The Increasing Photovoltaics Until 2013, April 2009, cited Intensity of the Strongest Tropical Cy- in Earth Policy Institute, Cumulative clones,” Nature 455: 92-95, 4 September Installed Solar Photovoltaics Capacity in the 2008. Heat waves: Andreas Sterl, et al., United States, 1998-2008 (Excel spread- Royal Netherlands Meteorological Insti- sheet), downloaded from www.earth- tute, “When Can We Expect Extremely policy.org/datacenter/xls/update83_5.xls,

Notes 53 4 November 2009. Oak Ridge Company Putting Hybrid Solar 19 Assumes a 16 percent capacity factor Lighting On Map (press release), 30 Au- for solar PV. gust 2005. 20 European Photovoltaic Industry 31 Judy Fosdick, “Passive Solar Heat- Association, Global Market Outlook for ing,” Whole Building Design Guide, up- Photovoltaics Until 2013, April 2009, cited dated 22 May 2008, downloaded from in Earth Policy Institute, Cumulative www.wbdg.org/resources/psheating.php Installed Solar Photovoltaics Capacity in the 11 November 2009. United States, 1998-2008 (Excel spread- 32 Sustainable Sources, Passive Solar De- sheet), downloaded from www.earth- sign, downloaded from passivesolar.sus- policy.org/datacenter/xls/update83_5.xls, tainablesources.com/, 31 December 2009. 4 November 2009. 33 U.S. Department of Energy, Of- 21 Kevin Bullis, “Mixing Solar With fice of Energy Efficiency and Renewable Coal to Cut Costs,” Technology Review, 4 Energy, Solar Energy Technologies Pro- September 2009. gram, Solar Collectors, 8 August 2006. 22 “Six new” from Solar Energy In- 34 U.S. Department of Energy, Office dustries Association, Major Solar Proj- of Energy Efficiency and Renewable En- ects in the United States Operational, ergy, Energy Savers, Active Solar Heating, Under Construction and Under Develop- 24 March 2009. ment, Updated 1/27/2010, downloaded 35 Solar Server, Cooling with Solar Heat: from www.seia.org/galleries/pdf/ Growing Interest in Solar Air Conditioning, Major%20Solar%20Projects.pdf, 2 Feb- downloaded from www.solarserver.de/so- ruary 2010. larmagazin/artikeljuni2002-e.html, 31 23 Andy Walker, National Renewable December 2009. Energy Laboratory, Solar Water Heating, 36 U.S. Census Bureau, American Hous- updated 27 May 2008, downloaded from ing Survey for the United States: 2007, Sep- www.wbdg.org/resources/swheating.php, tember 2008. 11 November 2009. 37 J. Kosny, T. Petrie, et al., Oak Ridge 24 Ibid. National Laboratory, Thermal Mass—En- 25 Ibid. ergy Savings Potential in Residential Build- 26 Ibid. ings, undated. 27 Bernadette Del Chiaro and Timothy 38 U.S. Department of Energy, Office Telleen-Lawton, Environment California of Energy Efficiency and Renewable En- Research and Policy Center and Frontier ergy, Five Elements of Passive Solar Home Group, Solar Water Heating: How Califor- Design, downloaded from www.ener- nia Can Reduce Its Dependence on Natural gysavers.gov/your_home/designing_re- Gas, April 2007. modeling/index.cfm/mytopic=10270, 10 February 2010. 28 Gregg D. Ander, Southern California Edison, Daylighting, updated 5 November 39 See note 27. 2008, downloaded from www.wbdg.org/ 40 Matt Daily, “Dow Sees Huge Market resources/daylighting.php 11 November in Solar Shingles,” Reuters, 6 October 2009. 2009. 29 Ibid. 41 See: Environment California, Solar 30 Oak Ridge National Laboratory, New Home Developments, downloaded from

54 Building a Solar Future www.environmentcalifornia.org/energy/ sector as a whole also applied to total million-solar-roofs/solar-home-develop- energy consumption (which includes con- ments, 31 December 2009. sumption of fossil fuels at power plants 42 Bernadette Del Chiaro, Environment that supply electricity to commercial California Research & Policy Center, buildings). Rave Reviews for Solar Homes: A Survey of 52 Kevin Ferguson, “Box Stores Target Homeowners in California, March 2006. Lighting Inefficiencies,”New York Times, 43 U.S. Department of Energy, Office Green Inc., 20 July 2009. of Energy Efficiency and Renewable En- 53 Walmart, Walmart Powers Facilities ergy, A Homebuilder’s Guide to Going Solar, with Solar Energy, 1 September 2009. December 2008. 54 Ed Acker, “Warehouse,” in Whole 44 Steve Dunn, Southwest Energy Ef- Building Design Guide, updated 2 July ficiency Project,High Performance Homes 2009. Downloaded from www.wbdg.org/ in the Southwest: Savings Potential, Cost design/warehouse.php on 16 November Effectiveness and Policy Options, November 2009. 2007. 55 World’s Largest Laundromat, World’s 45 Massachusetts Zero Net Energy Largest Laundromat, downloaded from Buildings Task Force, Getting to Zero: Fi- www.worldslargestlaundry.com/solar. nal Report of the Massachusetts Zero Net En- html, 16 November 2009. ergy Buildings Task Force, 11 March 2009. 56 Boston Red Sox, Red Sox Unveil Solar 46 Passive House Institute US, What Is Hot Water Panels at Fenway (press release), a Passive House?, downloaded from www. 19 May 2008. passivehouse.us/passiveHouse/Passive- 57 U.S. Department of Energy, Energy HouseInfo.html, 7 January 2010. Information Administration, Commercial 47 P. Denholm, National Renewable Building Energy Consumption Survey 2003, Energy Laboratory, The Technical Potential September 2008. of Solar Water Heating to Reduce Fossil Fuel 58 Davis Langdon, Cost of Green Revis- Use and Greenhouse Gas Emissions in the ited: Reexamining the Feasibility and Cost United States, March 2007. Impact of Sustainable Design in the Light of 48 U.S. Department of Energy, Office Increased Market Adoption, July 2007. of Energy Efficiency and Renewable En- 59 Gregory H. Kats, Massachusetts ergy, Energy Savers, The Economics of a Technology Collaborative, Green Building Solar Water Heater, 24 February 2009. Costs and Financial Benefits, 2003. 49 See note 47. 60 J. Paidipati, L. Frantzis, H. Sawyer, 50 See note 27. and A. Kurrasch, Navigant Consulting, 51 Based on an estimate of total energy Inc. for National Renewable Energy consumption attributable to commercial Laboratory, Rooftop Photovoltaics Market buildings, based on data from U.S. De- Penetration Scenarios, February 2008. partment of Energy, Energy Information 61 Ryan Wiser, Galen Barbose, Carla Administration, Annual Energy Outlook Peterman, and Naïm Darghouth, Law- 2010 Early Release, 14 December 2009. rence Berkeley National Laboratory, We assumed that the ratio of delivered Tracking the Sun II: The Installed Cost of energy consumption in commercial Photovoltaics in the U.S. from 1998-2008, buildings compared to the commercial October 2009.

Notes 55 62 See note 23. 74 Steinway & Sons, Steinway Installs 63 See note 1. World’s Largest Solar Cooling System (press release), 24 January 2009. 64 U.S. Department of Energy, Energy Information Administration, 2006 Manu- 75 U.S. Department of Energy, En- facturing Energy Consumption Survey, June ergy Information Administration, 2002 2009. Manufacturing Energy Consumption Survey, January 2007. 65 Claudia Vannoni, Ricardo Battisti, and Serena Drigo, International Energy 76 William McDonough and Partners, Agency, Solar Heating and Cooling Pro- Ford Truck Plant, downloaded from www. gramme, Potential for Solar Heat in Indus- mcdonoughpartners.com/projects/view/ trial Processes, 2008. ford_truck_plant, 31 December 2009. 66 European Solar Thermal Industry 77 See note 65. Federation, Solar Industrial Process Heat— 78 Clifton Carwile and Russell Hewitt, State of the Art, 25 August 2006. National Renewable Energy Laboratory, 67 See note 65. Barriers to Solar Process Heat Projects: Fif- teen Highly Promising (But Cancelled) Proj- 68 International Energy Agency, Solar ects, October 1994. Heat for Industrial Processes: Detailed Papers to Newsletter #1, downloaded from www. 79 European Union, Intelligent Ener- iea-ship.org/documents/papersofnewslet- gy—Europe: Project Fact Sheet: Solar Process terNo1.pdf, 31 December 2009. Heat, June 2009. 69 See note 65. 80 Randy Schnepf, Congressional Re- search Service, Energy Use in Agriculture: 70 Frito-Lay, Using the Power of the Sun Background and Issues, 19 November 2004. to Help Make Sunchips Multigrain Snacks (press release), 22 April 2008. 81 Ibid. 71 Alstrom Heat Transfer LLC, Frito- 82 Cathy Svejkovsky, National Sustain- Lay Solar System Puts the Sun in Sunchips, able Agriculture Information Service, Re- Takes Advantage of Renewable Energy, newable Energy Opportunities on the Farm, downloaded from www.alstromcorp. 2006. com/PDFCatalogue/Frito-Lay%20Solar 83 U.S. Department of Energy, Office %20%20Alstrom%20Newslatter_SE.pdf, of Energy Efficiency and Renewable En- 31 December 2009; 340 homes based on ergy, Energy Savers, Solar Energy Applica- average consumption per household of 43 tions for Farms and Ranches, 24 February million BTU from U.S. Department of 2009. Energy, Energy Information Administra- 84 Ibid. tion, 2005 Residential Energy Consumption Survey: Energy Consumption and Expendi- 85 See note 82. tures Tables, downloaded from www.eia. 86 See note 83. doe.gov/emeu/recs/recs2005/c&e/sum- 87 See note 82. mary/pdf/tableus4.pdf, 8 January 2010. 88 Ibid. 72 See note 66. 89 Wine Institute, California Sustainable 73 Soteris Kalogirou and Y. Tripanagnos- Winegrowing Alliance Highlights Progress topolous, “Industrial Applications of PV/T in Energy Savings (press release), 16 April Solar Energy Systems,” Applied Thermal 2009. Engineering, 27(8-9), 2007, 1259-1270.

56 Building a Solar Future 90 Lance Frazer, “Paving Paradise: The 101 Morris A. Pierce, University of Peril of Impervious Surfaces,” Environ- Rochester, Largest District Energy Systems, mental Health Perspectives 113(7): A456- downloaded from www.energy.rochester. A462, July 2005. edu/dh/largest.htm, updated June 2001. 91 Oregon Department of Transporta- 102 International District Energy As- tion, Innovative Partnerships Program, sociation, Downtown Utilities, downloaded downloaded from www.oregon.gov/ from www.districtenergy.org/assets/pdfs/ ODOT/HWY/OIPP/inn_solarhighway. DowntownUtilities.pdf, 31 December shtml, 31 December 2009. 2009. 92 Chevrolet Volt: Chevrolet, 2011 Volt: 103 International District Energy As- Introducing Chevrolet Volt, downloaded sociation, U.S. District Energy Systems, from www.chevrolet.com, 31 December downloaded from www.districtenergy. 2009. org/us-district-energy-systems, 31 De- 93 “Several other”: Plug-In America, cember 2009. Plug-in Vehicle Tracker, downloaded from 104 See, for example, European Com- www.pluginamerica.org/plug-in-vehicle- mission, Directorate-General for Energy tracker.html, 31 December 2009; Nissan and Transport, Solar District Heating: Leaf: Nissan, Nissan Unveils “LEAF”— Ballerup (Denmark), downloaded from The World’s First Electric Car Designed for www.energie-cites.org/db/ballerup_139_ Affordability and Real-World Requirements en.pdf, 31 December 2009; European (press release), 2 August 2009. Commission, Directorate-General for En- 94 Sherry Boschert, The Cleanest Cars: ergy and Transport, Solar District Heating: Well-to-Wheels Emissions Comparisons, May Friedrichshafen (Germany), downloaded 2008. from www.energie-cites.org/db/friedrich- shafen_139_en.pdf, 31 December 2009. 95 Toyota: Green Car Congress, Toyota Industries Corp. Develops Solar Charging 105 Thomas Schmidt, Janet Nussbicker Station for EVs and PHEVs, 26 December and Stefan Raab, Monitoring Results from 2009; “several companies,” Marty Gra- German Central Solar Heating Plants with ham, “Google Plants Solar Trees,” Wired, Seasonal Storage, paper presented to the 13 December 2006. ISES 2005 Solar World Congress, 6-12 August 2005. 96 See note 91. 106 B. Sibbitt, T. Onno, et al., The 97 Harriet Baskas, “Solar Powered Air- Drake Landing Solar Community Project— ports? It Could Happen,” USA Today, 28 Early Results, Power Point presentation April 2009. to Canadian Solar Buildings Conference, 98 Navigant Consulting, The Use of Re- 10-14 October 2007. newable Energy Sources to Provide Power to 107 EnerWorks, EnerWorks Supplies California’s High Speed Rail, 3 September World’s Largest Solar Heating and Cooling 2008. Installation, downloaded from www.ener- 99 International Maritime Organization, works.com/news_files/EnerWorks_Col- Prevention of Air Pollution from Ships, 9 lectors_Provide_Solar_CoolingTB.pdf, April 2009. 31 December 2009. 100 Christopher Shay, “Cleaning Up 108 Stephanie Simon, “Rural Electric Polluted Harbors with Greener Ships,” Co-ops Make Move into Alternative Ener- TIME , 28 October 2009. gy,” Wall Street Journal, 8 September 2009.

Notes 57 109 SunSmart, Governor Huntsman and faq.shtml, 20 January 2010. Mayor Help the St. George Utility Compa- 120 FPL, DeSoto Next Generation Solar nies Cut the Ribbon at the New SunSmart Center, downloaded from www.fpl.com/ Solar Farm (press release), 14 January environment/solar/desoto.shtml, 30 De- 2009. cember 2009. 110 Laura Snider, “Rep. Levy, D-Boul- 121 Solar Energy Industries Associa- der, to Introduce “Solar Gardens” Bill,” tion, Major Solar Projects in the United Daily Camera, 18 January 2010. States Operational, Under Construction and 111 North Carolina Solar Center and Under Development, Updated 1/27/2010, Interstate Renewable Energy Council, downloaded from www.seia.org/galler- DSIRE Solar: Massachusetts-Net Meter- ies/pdf/Major%20Solar%20Projects.pdf, ing downloaded from www.dsireusa. 2 February 2010. org/incentives/incentive.cfm?Incentive_ 122 P. Denholm and R. Margolis, Na- Code=MA01R&re=1&ee=1, 3 February tional Renewable Energy Laboratory, 2010. Very Large-Scale Deployment of Grid-Con- 112 See note 57. nected Solar Photovoltaics in the United 113 Ibid. States: Challenges and Opportunities, April 2006. 114 See, for example, Arthur van Ben- tham, Kenneth Gillingham and James 123 Ibid. Sweeney, “Learning-by-Doing and the 124 U.S. Department of Energy, Of- Optimal Solar Policy in California.” The fice of Energy Efficiency and Renewable Energy Journal, 29(3): 131-152, July 2008. Energy and Sandia National Laboratory, 115 Richard Perez, Clean Power Re- Solar Energy Grid Integration Systems “SE- search, Determination of Photovoltaic Effec- GIS”: Program Concept Paper, October tive Load Carrying Capacity for New Jersey, 2007. downloaded from www.cleanpower.com/ 125 Navigant Consulting, The Conver- research/capacityvaluation/ELCC_New_ gence of the Smart Grid with Photovoltaics: Jersey.pdf, 4 February 2010. Identifying Value and Opportunities, 20 116 See note 22. January 2009. 117 California Energy Commission, 126 U.S. Department of Energy, Energy Large Solar Energy Projects, downloaded Information Administration, Annual En- from www.energy.ca.gov/siting/solar/in- ergy Review 2008, 26 June 2009. dex.html, 30 December 2009. 127 Assumes a 16 percent capacity fac- 118 U.S. Department of Energy, Of- tor for solar PV. fice of Energy Efficiency and Renewable 128 Mark Mehos, National Renewable Energy, Solar FAQs—Concentrating Solar Energy Laboratory, Concentrating Solar Power—Applications, downloaded from Power, Power Point presentation to APS downloaded from www.eere.energy. Forum, 1-2 March 2008. gov/solar/cfm/faqs/third_level.cfm/nam 129 National Academy of Sciences, e=Concentrating%20Solar%20Power/ National Academy of Engineering and cat=Applications, 16 November 2008. National Research Council, Real Prospects 119 FPL, Martin Next Generation Solar for Energy Efficiency in the United States Energy Center FAQs, downloaded from (prepublication copy), 2010. www.fpl.com/environment/solar/martin_ 130 Note: these estimates are based on

58 Building a Solar Future previous estimates of energy consumption 135 15 cents: SolarPACES, ESTELA from earlier versions of the U.S. Energy and Greenpeace International, Concen- Information Administration’s Annual En- trating Solar Power Global Outlook 2009: ergy Outlook series of reports. Subsequent Why Renewable Energy Is Hot, 2009; 16 revisions that reflect both the economic cents: Mark Mehos, National Renewable downturn and the implementation of Energy Laboratory, Concentrating Solar more recent energy efficiency policies at Power, Power Point presentation to APS the state and federal level have reduced Forum, 1-2 March 2008. projected energy consumption in 2030 to 136 See note 60. 111 quads, per U.S. Department of En- ergy, Energy Information Administration, 137 Thomas P. Kimbis, U.S. Depart- Annual Energy Outlook 2010 Early Release, ment of Energy, Solar Energy Tech- 14 December 2009. nologies Program, Solar Energy Industry Forecast: Perspectives on U.S. Solar Market 131 The basis for this estimate is as Trajectory (presentation), 27 May 2008. follows: The U.S. Energy Information Administration’s Annual Energy Outlook 138 See, e.g., U.S. Department of En- 2010 report (see note 130 for full cita- ergy, Energy Information Administra- tion) projects that total primary energy tion, The Electricity Market Module of the consumption in 2030 will be approxi- National Energy Modeling System: Model mately 111 quadrillion Btu (quads). Of Documentation Report, February 2001. this figure, 46.6 quads are consumed in 139 See note 78. the production of electricity. The Na- 140 “more than 1 million” from Electric tional Academy of Science’s Real Prospects Drive Transportation Association, Hy- for Energy Efficiency in the United States brid Sales Figures/Tax Credits for Hybrids, (see note 129 for full citation) estimates downloaded from www.electricdrive. that cost-effective energy efficiency could org/index.php?ht=d/Articles/cat_id/5514/ reduce primary energy consumption for pid/2549, 20 January 2010. the production of electricity used in residential and commercial buildings by 14.4 141 California Solar Initiative, Califor- quads. Subtracting this from the AEO nia Solar Statistics, updated 30 December 2010 estimate results in primary energy 2009. consumption for electricity generation of 142 New Jersey Clean Energy Program, 32.2 quads. Assuming that PV averts 20 NJ Solar Installations as of 103109, (Excel percent of this energy consumption re- file), downloaded fromwww.njcleanen - sults in estimated savings of 6.4 quads. ergy.com, 7 January 2010. 132 See Schott North America, National 143 Environmental Law Institute, Esti- Poll Shows More Than Nine Out of 10 mating U.S. Government Subsidies to En- Americans Want Solar Now (press release), ergy Sources: 2002-2008, September 2009. 8 October 2009; ABC News/Washington 144 U.S. Department of Energy, NC Post poll conducted 13-17 August 2009, Solar Center and Interstate Renew- accessed at www.pollingreport.com/enable Energy Council, Database of State ergy.htm, 7 January 2010. Incentives for Renewables and Efficiency: 133 See note 61. Federal Residential Renewable Energy Tax 134 Jim Carbone, “Solar Photovoltaic Credit, downloaded from www.dsireusa. Systems Prices Continue Decline,” Pur- org/incentives/incentive.cfm?Incentive_ chasing, 2 December 2009. Code=US37F&re=1&ee=0, 7 January 2010.

Notes 59 145 U.S. Department of Energy, Council, DSIRE Solar: Federal Clean NC Solar Center and Interstate Re- Renewable Energy Bonds (CREBs), down- newable Energy Council, Database of loaded from www.dsireusa.org/solar/ State Incentives for Renewables and Ef- incentives/incentive.cfm?Incentive_ ficiency: Federal Business Energy Invest- Code=US45F&re=1&ee=1, 20 January ment Tax Credit, downloaded from 2010. http://www.dsireusa.org/solar/in- 150 New Mexico House Bill 610, 2007 centives/incentive.cfm?Incentive_ regular legislative session. Code=US02F&re=1&ee=0, 7 January 2010. 151 Lynda Arakawa, “Hawaii May Man- date Solar Water Heaters,” Honolulu Ad- 146 U.S. Department of Energy, Office vertiser, 14 March 2008. of Energy Efficiency and Renewable En- ergy, “Vermont Passes a Feed-in Tariff, 152 North Carolina Solar Center and Plus Other Clean Energy Measures,” Interstate Renewable Energy Council, EERE Network News, 3 June 2009. DSIRE Solar: Hawaii Solar Water Heating Requirement for New Residential Construc- 147 U.S. Department of Energy, Of- tion, downloaded from www.dsireusa.org/ fice of Energy Efficiency and Renewable solar/incentives/incentive.cfm?Incentive_ Energy, Federal Energy Management Pro- Code=HI13R&re=1&ee=1, 20 January gram: Federal Renewable Production and 2010. Consumption Requirements, downloaded from www1.eere.energy.gov/femp/tech- 153 European Solar Thermal Industry nologies/renewable_requirements.html, 4 Federation, Solar Industrial Process Heat— February 2010. State of the Art, 25 August 2006. 148 Eighteen states from North Caro- 154 U.S. Department of Energy, Trans- lina Solar Center, Interstate Renewable formational Energy Research Projects Win Energy Council, Property-Assessed Clean En- $151 Million in Funding (press release), 26 ergy, November 2009. October 2009. 149 North Carolina Solar Cen- ter and Interstate Renewable Energy

60 Building a Solar Future