Editing Heliostat (section)

==Large-scale projects==
In a solar-thermal power plant, like those of [[The Solar Project]] or the [[PS10]] plant in Spain, a wide field of heliostats focuses the Sun's power onto a single collector to heat a medium such as water or molten salt. The medium travels through a heat exchanger to heat water, produce steam, and then generate electricity through a steam turbine.{{Cn|date=March 2025}}

A somewhat different arrangement of heliostats in a field is used at experimental solar furnaces, such as the one at [[Font-Romeu-Odeillo-Via|Odeillo]], in France. All the heliostat mirrors send accurately parallel beams of light into a large paraboloidal reflector which brings them to a precise focus. The mirrors have to be located close enough to the axis of the paraboloid to reflect sunlight into it along lines parallel to the axis, so the field of heliostats has to be narrow. A [[Control theory#Closed-loop transfer function|closed loop]] control system is used. Sensors determine if any of the heliostats is slightly misaligned. If so, they send signals to correct it.{{Cn|date=March 2025}}

It has been proposed that the high temperatures generated could be used to split water producing hydrogen sustainably.<ref name=Hydrogen>{{Cite journal| first1 = D.| first2 = N.| first3 = M.| first4 = M.| first5 = C.| title = Economic comparison of solar hydrogen generation by means of thermochemical cycles and electrolysis| journal = International Journal of Hydrogen Energy| volume = 33| issue = 17| pages = 4511–4519| last1 = Graf| year = 2008| doi = 10.1016/j.ijhydene.2008.05.086| last2 = Monnerie| last3 = Roeb| last4 = Schmitz| last5 = Sattler}}</ref>