Solar Energy News

Grid-connected Photovoltaic Systems
Grid-connected photovoltaic systems, also called grid interface systems, supply surplus power back through the grid to the utility, and take from the utility grid when the home system’s power supply is low. These systems remove the need for battery storage, although arranging for the grid interconnection can be difficult. In some cases, utilities allow net metering, which allows the owner to sell excess power back to the utility.

Stand-Alone Photovoltaic Systems
Stand-alone systems produce power independently of the utility grid. In some off-the-grid locations as near as one-quarter mile from the power lines, stand-alone photovoltaic systems can be more cost-effective than extending power lines. They are especially appropriate for remote, environmentally sensitive areas, such as national parks, cabins, and remote homes. In rural areas, small stand-alone solar arrays often power farm lighting, fence chargers, and solar water pumps, which provide water for livestock. Direct-coupled systems need no electrical storage because they operate only during daylight hours, but most systems rely on battery storage so that energy produced during the day can be used at night. Some systems, called hybrid systems, combine solar power with additional power sources such as wind or diesel.

Building-Integrated Photovoltaics (BIPV)
Building-integrated photovoltaic materials are manufactured with the double purpose of producing electricity and serving as construction materials. They can replace traditional building components, including curtain walls, skylights, atrium roofs, awnings, roof tiles and shingles, and windows.

Concentrator Collectors
Concentrating photovoltaic collectors use devices such as Fresnel lenses, mirrors, and mirrored dishes to concentrate sunlight onto a solar cell. Certain solar cells, such as gallium arsenide cells, can efficiently convert concentrated solar energy into electricity, allowing the use of only a small amount of semiconducting material per square foot of solar collector. Concentrating collectors are usually mounted on a two-axis tracking system to keep the collector pointed toward the sun.