The flavors of solar
Solar power refers to the sun’s energy — no matter how people harvest it. A house with “passive solar” simply means it has windows facing the south that can warm the home and lower heating bills.
The two principle ways to turn sunlight into electricity are photovoltaic panels and solar-thermal plants.
Photovoltaics: PV panels rely on the sun’s energy to excite electrons in the panel’s semi-conductor material. The excited electrons leave their normal positions around their atoms and become a part of an electrical flow. PV panels are a relatively expensive way to create electricity, but the prices are coming down. They work well on rooftops and for individual buildings.
Solar-thermal plants: Currently, it’s more cost-effective to build large solar-power plants using solar-thermal technologies to produce “concentrated solar power.” This technique uses large amounts of mirrors to focus the sun’s rays on a liquid. The liquid heats up and warms water to create steam that then powers a traditional turbine. These plants can also be easily hybridized with more traditional fuel sources to compensate when the sun isn’t shining.