
The Savonius turbine is one of the simplest turbines. , it is a -type device, consisting of two or three scoops. Looking down on the rotor from above, a two-scoop machine might resemble the letter "S" in . Because of the , the scoops experience less drag when moving against the wind than when moving with the wind. The differential drag causes the Sa.

CSP is used to produce electricity (sometimes called solar thermoelectricity, usually generated through ). Concentrated solar technology systems use or with systems to focus a large area of sunlight onto a small area. The concentrated light is then used as heat or as a heat source for a conventional (solar thermoelectricity). The solar concentrators use.