Solar energy and the environment

Impact
Land Hazardous wastes (lead-acid batteries in PV and solar thermal)
Heavy metals (used in PV)
Land use (from large interconnected PV systems)

During operation, solar energy technologies produce no air pollution, no noise and require no transportable fuels.

One environmental concern with PV and solar thermal technologies is the lead-acid batteries used in some systems. The impact of these batteries is lessening, however, as batteries become more recyclable and longer-life batteries are used.

Another environmental concern is the potential impacts of heavy metals used in PV cells. Advanced PV technologies rely on semiconductor materials that incorporate heavy metals such as cadmium and selenium. While these metals are toxic, the quantities involved are small (for example, a PV module of one metre may contain six grams of cadmium, compared with 2.5 grams in a nickel cadmium penlight battery).

Also, when constructed as large interconnected systems, PV solar installations may require large amounts of land, which in turn can affect local ecosystems (utility-scale solar power plants would require about one square kilometre for every 20 to 60 megawatts). However, small-scale distributed applications are more common, taking advantage of unused space on the roofs of homes and buildings and in city and industrial lots.