Concentrating Solar Power

Renewable Energy World has a comprehensive overview of Concentrating Solar Power. Spain is the big player now, the US plans multi-gigawatts of CSP soon. Progress has been slow due to permits and delays, but production should be ramping up fast in the next few years.

CSP uses mirrors to focus the sun on pipes filled with liquid, often water, heating it up to create steam which then powers turbines. It costs more than photovoltaics, however the heat can be stored for later use in molten salt, thus it can produce energy at night too.