QUADRENNIAL TECHNOLOGY REVIEW AN ASSESSMENT OF ENERGY TECHNOLOGIES AND RESEARCH OPPORTUNITIES Chapter 1: Energy Challenges September 2015 1 Energy Challenges Energy is the Engine of the U.S. Economy Quadrennial Technology Review 1 1 Energy Challenges 1.1 Introduction The United States’ energy system, vast in size and increasingly complex, is the engine of the economy. The national energy enterprise has served us well, driving unprecedented economic growth and prosperity and supporting our national security. The U.S. energy system is entering a period of unprecedented change; new technologies, new requirements, and new vulnerabilities are transforming the system. The challenge is to transition to energy systems and technologies that simultaneously address the nation’s most fundamental needs—energy security, economic competitiveness, and environmental responsibility—while providing better energy services. Emerging advanced energy technologies can do much to address these challenges, but further improvements in cost and performance are important.1 Carefully targeted research, development, demonstration, and deployment (RDD&D) are essential to achieving these improvements and enabling us to meet our nation’s energy objectives. This report, the 2015 Quadrennial Technology Review (QTR 2015), examines science and technology RDD&D opportunities across the entire U.S. energy system. It focuses primarily on technologies with commercialization potential in the mid-term and beyond. It frames various tradeoffs that all energy technologies must balance, across such dimensions as diversity and security of supply, cost, environmental impacts, reliability, land use, and materials use. Finally, it provides data and analysis on RDD&D pathways to assist decision makers as they set priorities, subject to budget constraints, to develop more secure, affordable, and sustainable energy services. The energy science and technology RDD&D opportunities described in this report, if successfully conducted and commercialized at scale, would significantly impact the energy security, economic, and environmental challenges that face the United States and the world. 1.2 The U.S. Energy System A vast and complex array of systems and associated technologies extract energy resources, convert them into usable forms of energy, and deliver them to end users to provide desired services such as manufactured goods, thermal comfort, lighting, and mobility. The overall flow of energy through the U.S. energy system is illustrated in Figure 1.1.2 It illustrates the initial energy resources, their conversions into fuels and electricity, and their use in the buildings, industry, and transportation sectors to provide the energy services that support our economy and our way of life. It also illustrates energy losses (rejected energy) that result from the fact that energy conversion processes are never 100% efficient. 1 Energy Challenges Figure 1.1 The Sankey Diagram depicts the flow of energy resources (left) to end-use sectors (right). Credit: Lawrence Livermore National Laboratory Estimated U.S. Energy Use in 2014: ~98.3 Quads Net Electricity Imports 0.164 Solar 0.170 0.427 8.33 12.4 25.8 Nuclear Electricity 8.37 8.33 Generation Rejected 2.44 38.4 Energy Hydro 16.4 59.4 2.47 4.12 1.73 4.79 Wind 1.73 0.159 Residential 0.252 11.8 7.66 0.0197 Geothermal 0.945 0.202 0.580 5.20 3.13 0.0197 4.63 Natural Commercial Gas 8.93 5.81 27.5 3.55 Energy 0.561 Services 0.0257 0.0470 38.9 4.95 3.26 0.119 Coal 9.46 Industrial 17.9 24.7 19.8 8.16 1.51 2.30 0.507 Biomass 21.4 4.78 1.27 0.0265 0.294 0.942 Trans- 24.8 portation 27.1 Petroleum 5.68 34.8 1.2.1 U.S. Energy Supply and Use Figures 1.2 and 1.3 provide more detail on the energy inputs and applications within the buildings, industrial, and transportation sectors. Fossil fuels supply about 82% of the primary energy use in the United States. The challenges and opportunities associated with fossil fuels are explored in Chapters 4 (Advancing Clean Electric Power Technologies) and 7 (Advancing Systems and Technologies to Produce Cleaner Fuels), as well as elsewhere throughout the report. There are many pathways to produce electricity, with the generation mix currently dominated by coal, natural gas, and nuclear resources. Options for improving the performance of the electricity grid are described in Chapter 3 (Enabling Modernization of the Electric Power System), while options for developing cleaner, more competitive, and more secure supplies are described in Chapter 4. The buildings sector is the largest consumer of electricity, and electricity supplies the majority of primary energy that is consumed in buildings. Buildings sector energy technology opportunities, discussed in Chapter 5 (Increasing Efficiency of Building Systems and Technologies), are thus heavily weighted toward technologies powered by electricity. The industrial sector is the most diverse consumer of energy, and also has the most diverse set of energy applications. This sector includes manufacturing (the focus here) as well as agriculture, construction, and mining. Opportunities to address energy challenges in the manufacturing sector, in particular, are likewise diverse, and are discussed in Chapter 6 (Innovating Clean Energy Technologies in Advanced Manufacturing). 12 Quadrennial Technology Review The energy inputs for the transportation sector are almost completely dominated by petroleum-based fuels. Energy use in this sector is dominated by light-duty vehicles. Opportunities to displace and/or improve the use of petroleum fuels in light-duty vehicles are considered first, with other important opportunities discussed in somewhat less detail. Chapters 7 and 8 (Advancing Clean Transportation and Vehicle Systems and Technologies) cover the fuels and transportation space. 1 U.S. Energy: Supplies and Sectoral Uses3 Figure 1.2a U.S. Primary Energy (a) Supply and (b) Consumption in the End-Use Sectors in quads and as a percent of total U.S. primary energy, respectively. Note that fossil fuels supply about 82% of U.S. primary energy consumption. 2014 Primary Energy Supply 2014 Primary Energy End Use by Sector Biomass, 2.8 Q, Wind, 1.7 Q, 2% Other 3% Renewable, 0.8 Other, 0.4 Q, 0% Q, 1% Hydropower, 2.4 Biomass liquids, Q, 2% 1.3 Q, 1% Transport, 26.8 Nuclear, 8.2 Q, Q, 27% 8% Buildings, 40.1 Q, 41% Oil and gas 98.5 Quads liquids, 34.7 Q, 98.4 Quads 35% Coal, 18.3 Q, 19% (2014) (2014) Natural gas, 27.9 Industry, 31.5 Q, Q, 28% 32% Figure 1.2b U.S. Electric Power by (a) Total Primary Input (quads) and Electricity Generation by Source (kWh and %); and (b) Electricity End Use by Sector in kWh and as a percentage of total U.S. electricity generation. Note that coal is the largest source of energy and the buildings sector accounts for 74% of electricity consumption. Primary Energy Input and Electricity Generation by Source Electricity Sales by Sector Solar, 18 BkWh, 0.4% Wind, 182 BkWh, 4.4% Biomass and Waste, 64 BkWh, 1.6% Other, 12 BkWh, 0.3% Transportation, Geothermal, 16.6 BkWh, 0.4% Industry, 8 BkWh, 0.2% 955 BkWh, 25.7% Hydropower, 259 BkWh, 6.3% Coal, 1,585 BkWh, 38.8% Nuclear power, 39 Quads 39 Quads 797 BkWh, 19.5% (2014) (2014) Petroleum, Buildings, 30 BkWh, 0.75% Natural gas, 2,760 BkWh, 74.1% 1,122 BkWh, 27.5% 13 1 Energy Challenges Use Sectors: Supplies and End Uses4,5,6,7 Figure 1.3a Building Sector Energy by (a) Primary Energy Supply and (b) Energy End Uses in quads and as a percent of total U.S. building energy supply and use. Note that the building sector directly uses large amounts of natural gas. Building Sector Energy Supply Building Sector End Use Marketed Furnace fans and renewables, 0.7 Other fuels, 0.7 boiler circulation Q, 2% Q, 2% pumps, 0.5 Q, 1% Other uses, 11.1 Ventilation, 1.6 Distillate Fuel Oil, Q, 28% Q, 4% 0.9 Q, 2% Space heating, 9 Natural Gas, 8.8 Q, 22% Q, 22% 40.1 Quads 40.1 Quads (2014) (2014) Electronics, 2.3 Q, 6% Electricity, 28.9 Appliances, 1.3 Space cooling, Q, 72% Q, 3% 3.5 Q, 9% Cooking, 0.8 Q, Lighting, 4.3 Q, 2% Refrigeration, 2.2 11% Q, 6% Water heating, 3.5 Q, 9% Figure 1.3b Industry Sector Energy by (a) Primary Energy Supply and (b) Energy End Uses in quads and as a percent of total U.S. industry energy supply and use. Note that natural gas and petroleum dominate energy use in the industry sector. Much of the energy is used for energy- intensive commodity materials processing. Industry Sector Energy Supply Industry Sector End Use Hydropower, 0 Q, Biomass, 1.3 Q, 0% Municipal waste, 4% Nonfuel uses, 4.3 0.2 Q, 1% Q, 14% Petroleum and Coal Products, Petroleum and Non- 5.2 Q, 17% Purchased other liquids, 8.2 manufacturing electricity, 10 Q, Q, 26% 32% heat and power, 4.0 Q, 13% 31 Quads 31 Quads Chemicals, 5.0 Q, 17% (2014) (2014) Other Sectors, 2.5 Q, 8% Biofuels heat and Food, 1.8 Q, 6% Paper, 3.3 Q, 11% coproducts, 0.6 Natural gas, 9.7 Q, 2% Q, 31% Nonmetallic Coal, 1.5 Q, 5% Mineral Products, Primary Metals, Wood Products, 1.1 Q, 4% 2.6 Q, 8% 0.7 Q, 2% Figure 1.3c Transportation Sector Energy by (a) Primary Energy Supply and (b) Energy End Uses in quads and as a percent of total U.S. transportation energy supply and use. As can be seen, the transportation sector is almost entirely dependent on petroleum.