Solar power is the result of converting sunlight into electricity. Sunlight can be converted directly into electricity using photovoltaics (PV), or indirectly with concentrating solar power (CSP), which normally focuses the sun's energy to boil water which is then used to provide power. The largest solar power plants, like the 354 MW SEGS, are concentrating solar thermal plants, but recently multi-megawatt photovoltaic plants have been built. Completed in 2008, the 46 MW Moura photovoltaic power station in Portugal and the 40 MW Waldpolenz Solar Park in Germany are characteristic of the trend toward larger photovoltaic power stations. Much larger ones are proposed, such as the 550 MW Topaz Solar Farm, and the 600 MW Rancho Cielo Solar Farm.
Solar power is a predictably intermittent energy source, meaning that whilst solar power is not available at all times, we can predict with a very good degree of accuracy when it will and will not be available. Some technologies, such as solar thermal concentrators with an element of thermal storage, have the potential to eliminate the intermittency of solar power, by storing spare solar power in the form of heat; and using this heat overnight or during periods that solar power is not available to produce electricity. This technology has the potential to make solar power "dispatchable", as the heat source can be used to generate electricity at will. Solar power installations are normally supplemented by storage or another energy source, for example with wind power and hydropower.