Photovoltaics.

Solar cells, or photovoltaic cells, transform light, usually sunlight, into electric current. Few power-generation technologies are as clean as photovoltaics (PV). As it silently generates electricity, PV produces no air pollution or hazardous waste. It doesn't require liquid or gaseous fuels to be transported or combusted. And because sunlight is free and abundant, PV systems, especially baseload Space Solar Power, may eliminate uncertainties surrounding oil, gas, or other energy fuel supplies from politically unstable regions.