CSP: STORING SOLAR HEAT

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One of the attractions of CSP is that it is possible to store solar heat in melted salts (such as nitrates of sodium or potassium) so that electricity generation may continue through the night or on cloudy days. This has been demonstrated in the Solar Two power tower and in the parabolic trough type of CSP plant. There is more information on the NREL page about solar thermal storage.

With the use of heat storage, it is possible for a CSP plant to deliver both 'dispatchable' power (power that can respond flexibly to peaks and troughs in demand) and 'base load' power (background supplies that do not respond to variations in demand).

A related point is that CSP plants of the type that raise steam and drive a turbine can use gas power as an alternative source of heat as a backup when there is no sun. This strengthens the plant's capability for supplying dispatchable power.