Building integrated photovoltaic : a sustainable and aesthetically pleasant energy source in buildings

Abstract

The use of PV power systems around the world is increasing. PV is rapidly changing from 'high-tech' electricity supply for space travel to an everyday source of energy. Photovoltaics are an elegant means of producing electricity on site, directly from the sun, without concern for fuel supply or environmental impact. Solar power is produced silently with no maintenance, no pollution and no depletion of resources. Photovoltaics are also exceedingly versatile - the same technology that can pump water, grind grain and provide communications and village electrification in situations where no electricity is available, can produce electricity for the buildings and distribution grids of the industrialized countries. In locations where no electricity grid is available, PV can be a technically feasible and cost-effective solution. The application of PV in stand-alone electricity consumers such as isolated houses, light buoys and telecommunication systems, represent a huge potential market. Indeed, from the Arctic to the Equator, numerous stand-alone systems are being equipped with PV, bringing renewable, environmentally friendly energy to offgrid areas. A different type of application of PV is the grid-connected PV-system producing clean solar power for the electricity grid. It is expected that in the next century this type of PV system will contribute substantially to the main-stream power production, though power produced by photovoltaics in most occasions is still more than five times as expensive as energy from the grid. Further substantial cost reductions are required. The economic improvement of photovoltaics occurs not only through the increasing efficiency of solar cells. Cost reductions can also be achieved through the integration of grid-connected photovoltaics into the built environment (BIPV). PV installations can be installed on surfaces of buildings, along roads or railways, allowing the possibility to combine energy production with other functions of the building envelope, such as roof and facade integration, sun blinds and solar thermal collectors. Cost savings through these combined functions can be substantial, e.g. in expensive facade systems where cladding costs may equal the costs of the PV modules. Additionally, no high-value land is required, and no separate support structure is necessary. Electricity is generated at the point of use. This avoids transmission and distribution losses and reduces the utility company's capital and maintenance costs. The integration of PV into the architectural design offers more than cost benefits, however. It also allows the designer to create environmentally benign and energy efficient buildings without sacrificing comfort, aesthetics or economy.