Integrating Thin­Film Photovoltaics Onto Building Envelope Surfaces Michael Gumm Corporate Roof Consultants, LLC Seminole, Florida Proceedings of the RCI 23rd International Convention Gumm ­ 101 ABSTRACT This paper covers design and installation methods for Building Integrated Photovol­ taics (BIPV) using the new thin­film photovoltaic module technologies with conven­ tional construction products over the following building envelope surfaces: • Single­ply, modified bitumen, and metal roofs • EIFS and concrete and masonry wall surfaces • Concrete surfaces, such as parking lots and architectural elements Installation methods include thin­film photovoltaic modules laminated to single­ply membranes; flexible photovoltaic modules combined with elastomeric coatings applied over roofs, concrete, and walls; and re­deployable photovoltaic systems with magnetic membranes for metal roof applications and self­ballasted insulated roof panels. The subject matter covers new construction and building restorations. Information for array design and the various finance options available to owners is also provided. SPEAKER Michael Gumm has been actively involved in the roofing industry for the past 25 years in manufacturing, sales, contracting, and consulting. He is the founder and president of SolarPower Restoration Systems Inc. and SolarSeal Technologies Inc. Both companies are engaged in developing new building­integrated photovoltaic (BIPV) application technologies. Mr. Gumm is a BIPV pioneer and inventor with five patents pending covering a number of BIPV application technologies using conven­ tional building products with photovoltaic systems to create new building envelope surfaces that both weatherproof and generate renewable energy from the sun Contact Information: Phone – 727­230­3269; E­mail – [email protected] Gumm ­ 102 Proceedings of the RCI 23rd International Convention Integrating Thin­Film Photovoltaics Onto Building Envelope Surfaces INTRODUCTION: Crystalline Silicon The industry standard for We are all familiar with the solar technology since photovolta­ basic photovoltaic glass module ic systems have been installed on mounted on racks or posts. buildings has been glass­mount­ Glass­encapsulated photovoltaics ed, silicon­based solar panels. are the most common type of Today, a new type of photovoltaic solar module. Most rack­mounted technology called thin­film photo­ PV modules consist of crystalline silicon – either as a single or as a voltaic technologies is ready to Figure 1 – Crystalline sili­ poly­crystalline wafer to generate change the way photovoltaics are con array on the New York electricity. installed on buildings. This paper State Energy Research & is written to give our industry a Development Authority’s • Silicon­based photovol­ broad overview of both old and Voorheeville, NY, school. taics have the highest new solar technology plus insight electrical output of any on designing and applying these photovoltaic material per photovoltaic systems. According sq ft. to the Solar Energy Industry These newer technologies, called Association, solar power in 2006 • Typical power production thin­film photovoltaics, include represented only one­tenth of one is between 12 to 15 watts very thin layers of photovoltaicly percent of the added electrical per sq ft. active material placed on a glass power capacity to the U.S. power • Silicon wafer photovoltaics superstrate, flexible metal, or grid. In three years, solar will are more expensive and plastic substrates. Flexible thin­ grow to 15 percent of added require large amounts of film PV modules are made by capacity and by 2018, solar is energy to manufacture. depositing semiconductor materi­ expected to contribute 50 percent Silicon modules costs als on stainless steel foil or a plas­ of the annual U.S. power increase. $4.85 per watt on aver­ tic carrier and encapsulating with If you have not seen solar on a age.1 a solar transparent plastic poly­ project in the past, chances are • In 2006, solid silicon pho­ mer. you will in the near future. tovoltaic modules repre­ Semiconductor materials used sented about 95% of all PHOTOVOLTAIC BASICS in thin­film photovoltaics include: solar panels installed. Photovoltaics (PV) are one of • Amorphous silicon (a­Si) : Uni­solar and MWOE­ the most promising sustainable Other building system appli­ solar energy technologies. Solar PV cations include semi­transparent modules produce electricity on photovoltaic glass modules for • Copper indium gallium site, directly from the sun, with windows and skylights using diselenide (CIGS): Mia the least environmental harm. crystalline silicon, and one PV solé, NanoSolar and Solar has the smallest environ­ manufacturer has integrated thin Global Solar mental impact of any of the silicon wafers into a single­ply • Cadmium telluride (CdTe): renewable energy systems. Photo­ roofing product. Leading silicon First Solar voltaic modules are solid­state panel manufacturers include devices that simply make electric­ SunPower, Sharp, Schott Solar, Other new solar technologies ity from sunlight. They require lit­ Sharp Corporation, and Canon Inc. tle maintenance, produce no pol­ in development include dye­sensi­ lution, and don't deplete any non­ Thin­Film Photovoltaics tized solar cells using a dye­ impregnated layer of titanium renewable fossil energy resources A number of new photovoltaic dioxide to generate electricity. such as oil, natural gas, and coal. technologies have begun to Dye­sensitized solar cells will be emerge into the marketplace. printed onto various polymer Proceedings of the RCI 23rd International Convention Gumm ­ 103 films with equipment resembling The power storage system computer printers. Thin­film pho­ is essentially free. tovoltaic materials are used in • Both the building owner both glass­encapsulated and flex­ and the utility benefit with ible­membrane solar modules. grid­tied BIPV, as on­site Thin­film photovoltaics' differ­ solar power production is ence over traditional silicon mod­ typically greatest during a ules include: building and power com­ pany's peak energy needs. • Thin­film photovoltaics • The photovoltaic system Figure 2 – Flexible, thin­ generate less power per sq reduces energy costs for film photovoltaic module ft than crystalline silicon, the building owner, and at Grand Valley State but produce more overall the exported surplus solar University, displaying Uni­ total power output over energy provides additional Solar thin­film solar cells. the solar day compared to power to the utility grid silicon­based photovol­ during the time of its taics. Thin­film photo vol­ greatest energy demand. taics do this because they because rebates and incentives produce more power in low • The utility company can are priced out in watts. and overcast light condi­ maintain needed power tions compared with crys­ production capacity with­ BUILDING INTEGRATED PHOTO­ talline silicon. Most power out the capital investment VOLTAICS (BIPV) SYSTEMS measurements for silicon of building new power gen­ are taken during peak Building­Integrated Photovol­ eration plants. power production times at taics (BIPV) is a new sustainable­ • The building owner can midday. energy­source building technolo­ draw back the net­metered gy. Photovoltaics are one of the power at night, typically • Thin­film photovoltaics on most promising renewable ener­ when electrical costs are average produce 6 to 10 gy­source building technologies. A lower, helping to reduce watts of power per sq ft, BIPV system consists of integrat­ the cost of utility­generat­ depending on the type of ing photovoltaic modules into the ed power. semiconductor material building envelope with conven­ used. • Photovoltaic systems can tional building products, such as • Thin­film solar photovol­ become the building's pri­ the roof, windows, or walls. BIPV taics' power production is mary energy source in the is simultaneously both the build­ not affected by higher en­ event of a power failure ing envelope surface and the vironmental operating and energy can be stored building energy source. temperatures. Silicon­ onsite for emergency back­ based modules start drop­ BIPV Advantages up using batteries. ping power output once • A building owner's BIPV BIPV systems are available for module temperature ex­ system is connected with a number of building­envelope ceeds 25 degrees C. the local utility grid, and surfaces, including roofs, walls, • Solar shading does not with net metering, can windows, and concrete. lower the entire thin­film export surplus energy to module power output. the utility for use later, ROOFING AND BIPV when the building requires Placing rigid solar photovolta­ Thin­film photovoltaics cost utility energy. ic roof panels as a stand­alone or less than silicon modules. Aver­ • The building becomes a roof­top, equipment­mounted age cost, depending on the type of power distributor at the power module array has been semi­conductor material used point of use by net meter­ around since the invention of and if the module substrate is ing the building's surplus solar­photovoltaic cells. The cre­ glass or polymer­encapsulated, is power production. Think ative idea of integrating thin­film between $3.00 and $4.24 a watt.2 of net metering as a PV modules into a roofing system Power production per sq ft varies method to bank or deposit dates back to the 1980s. Only between manufacturers; the solar surplus solar energy pro­ recently, with the commercial industry tends to price product duction during the day development of newer,