Building-integrated photovoltaics (BIPV) are photovoltaic materials that are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades. They are increasingly being incorporated into the construction of new buildings as a principal or ancillary source of electrical power, although existing buildings may be retrofitted with similar technology. The advantage of integrated photovoltaics over more common non-integrated systems is that the initial cost can be offset by reducing the amount spent on building materials and labor that would normally be used to construct the part of the building that the BIPV modules replace. These advantages make BIPV one of the fastest growing segments of the photovoltaic industry.
The term building-applied photovoltaics (BAPV) is sometimes used to refer to photovoltaics that are a retrofit - integrated into the building after construction is complete. Most building-integrated installations are actually BAPV. Some manufacturers and builders differentiate new construction BIPV from BAPV.
PV applications for buildings began appearing in the 1970s. Aluminum-framed photovoltaic modules were connected to, or mounted on, buildings that were usually in remote areas without access to an electric power grid. In the 1980s photovoltaic module add-ons to roofs began being demonstrated. These PV systems were usually installed on utility-grid-connected buildings in areas with centralized power stations. In the 1990s BIPV construction products specially designed to be integrated into a building envelope became commercially available. A 1998 doctoral thesis by Patrina Eiffert, entitled An Economic Assessment of BIPV, hypothesized that one day there would an economic value for trading Renewable Energy Credits (RECs). A 2011 economic assessment and brief overview of the history of BIPV by the U.S. National Renewable Energy Laboratory suggests that there may be significant technical challenges to overcome before the installed cost of BIPV is competitive with photovoltaic panels.
Building-Integrated Photovoltaic modules are available in several forms.
- Flat roofs
- Pitched roofs
- Modules shaped like multiple roof tiles.
- Solar shingles are modules designed to look and act like regular shingles, while incorporating a flexible thin film cell.
- It extends normal roof life by protecting insulation and membranes from ultraviolet rays and water degradation. It does this by eliminating condensation because the dew point is kept above the roofing membrane.
- Facades can be installed on existing buildings, giving old buildings a whole new look. These modules are mounted on the facade of the building, over the existing structure, which can increase the appeal of the building and its resale value.
- (Semi)transparent modules can be used to replace a number of architectural elements commonly made with glass or similar materials, such as windows and skylights.
Transparent and translucent photovoltaics
Transparent solar panels use a tin oxide coating on the inner surface of the glass panes to conduct current out of the cell. The cell contains titanium oxide that is coated with a photoelectric dye.
Most conventional solar cells use visible and infrared light to generate electricity. In contrast, the innovative new solar cell also uses ultraviolet radiation. Used to replace conventional window glass, or placed over the glass, the installation surface area could be large, leading to potential uses that take advantage of the combined functions of power generation, lighting and temperature control.
Another name for transparent photovoltaics is “translucent photovoltaics” (they transmit half the light that falls on them). Similar to inorganic photovoltaics, organic photovoltaics are also capable of being translucent.
In some countries, additional incentives, or subsidies, are offered for building-integrated photovoltaics in addition to the existing feed-in tariffs for stand-alone solar systems. Since July 2006 France offered the highest incentive for BIPV, equal to an extra premium of EUR 0.25/kWh paid in addition to the 30 Euro cents for PV systems. These incentives are offered in the form of a rate paid for electricity fed to the grid.
- France €0.25/kWh
- Germany €0.05/kWh facade bonus expired in 2009
- Italy €0.04 - €0.09/kWh
- Spain, compared with a non- building installation that receives €0.28/kWh (RD 1578/2008):
- ≤20 kW, €0.34/kWh
- >20 kW: €0.31/kWh
- USA - Varies by state. Check Database of State Incentives for Renewables & Efficiency for more details.
Further to the announcement of a subsidy program for BIPV projects in March 2009 offering RMB20/watt for BIPV systems and RMB15/watt for rooftop systems, the Chinese government recently unveiled a photovoltaic energy subsidy program “the Golden Sun Demonstration Project”. The subsidy program aims at supporting the development of photovoltaic electricity generation ventures and the commercialization of PV technology. The Ministry of Finance, the Ministry of Science and Technology and the National Energy Bureau have jointly announced the details of the program in July 2009. Qualified on-grid photovoltaic electricity generation projects including rooftop, BIPV, and ground mounted systems are entitled to receive a subsidy equal to 50% of the total investment of each project, including associated transmission infrastructure. Qualified off-grid independent projects in remote areas will be eligible for subsidies of up to 70% of the total investment. In mid November, China’s finance ministry has selected 294 projects totaling 642 megawatts that come to roughly RMB 20 billion ($3 billion) in costs for its subsidy plan to dramatically boost the country’s solar energy production.
- Renewable energy
- Roof tile
- Solar cell
- Solar panel
- Solar power
- Solar thermal
- Zero-energy building
- Smart glass is a type of window blind capable of conserving energy for cooling
- Agrawal, Basant; Tiwari, G N (2011). 1 Building Integrated Photovoltaic Thermal Systems. Cambridge, UK: Royal Society of Chemistry. ISBN 978-1-84973-090-7.
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- Eiffert, Patrina; Kiss, Gregory J. (2000). Building-Integrated Photovoltaic Designs for Commercial and Institutional Structures: A Source Book for Architect. p. 59. ISBN 978-1-4289-1804-7.
- Eiffert, Patrina (1998). An Economic Assessment of Building Integrated Photovoltaics. Oxford Brookes School of Architecture.
- James, Ted; Goodrich, A.; Woodhouse, M.; Margolis, R.; Ong, S. (November 2011). "Building-Integrated Photovoltaics (BIPV) in the Residential Sector: An Analysis of Installed Rooftop System Prices." NREL/TR-6A20-53103.
- Eiffert, Patrina (2000). Building-Integrated Photovoltaic Designs for Commercial and Institutional Structures: A Source Book for Architect. pp. 60–61.
- Henemann, Andreas (2008-11-29). "BIPV: Built- in Solar Energy". Renewable Energy Focus (Science Direct) 9 (6): 14, 16–19. doi:10.1016/S1471-0846(08)70179-3.
- West, Mike (November 1992). "Transparent PV Panel". Energy Efficiency and Environmental News (Florida Energy Extension Service, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida). Retrieved October 5, 2011.
- "Subsidies: France moves up, Netherlands down". Eugene Standard. 2006. Retrieved 2008-10-26. "30 €ct per kilowatt-hour (40 €ct for Corsica) for twenty years, while an extra premium of 25 €ct/kWh is received for roof-, wall- or window-integrated PV. Moreover, individual households also can receive a 50% tax credit for their PV investments."
- "CLER - Comité de Liaison Energies Renouvelables". CLER. 2008-06-03. Retrieved 2008-10-26. "30 à 55* c€/kWh en France continentale"
- PV Subsidies: France up, Netherlands down | Leonardo ENERGY
- "DSIRE Home". dsireusa.org. 2011. Retrieved October 5, 2011.
- "China launches "Golden Sun" subsidies for 500 MW of PV projects by 2012". snec.org.cn. SNEC PV. 2011. Retrieved October 5, 2011. "China launched its much anticipated Golden Sun program of incentives for the deployment of 500 MW of large-scale solar PV projects throughout the country on July 21."
- "The Golden Sun of China". pvgroup.org. PV Group. 2011. Retrieved October 5, 2011.
- Wang, Ucilia (November 16, 2009). "Here Comes China’s $3B, ‘Golden Sun’ Projects". Greentech Media. Retrieved October 5, 2011.
- Building integrated photovoltaics an overview of the existing products and their fields of application
- Canadian Solar Buildings Research Network
- Wisconsin Public Service Corporation: Building-Integrated Photovoltaics (buildingsolar.com)[dead link]
- PV UP-SCALE, a European founded project (contract EIE/05/171/SI2.420208) related to the large-scale implementation of photovoltaics (PV) in European cities.