Inexpensive Solar Thermal Power Plant

[EdEarl]

 

thinkprogress.org

 

Converting sunlight directly into electricity, the photovoltaic (PV) solar panel industry has dominated the solar generation market recently because of its astounding price drops. Prices have fallen 99 percent in the past quarter century and over 80 percent since 2008 alone. This has also helped to slow the growth of the “other” form of solar, concentrating solar thermal power (CSP), which uses sunlight to heat water and use the steam to drive a turbine and generator.

A picture in that article shows Nevada's Crescent Dunes concentrating solar system that generates 110 Megawatts and stores heat for overnight generation.

It appears the mirrored area has been meticulously prepared; moreover, there might be a design that minimizes money spent for site preparation. It requires a swarm of mirrors on a cart with three independently steered wheels. The cart can point the mirror in any direction around the compass; thus, the mirror must position angular elevation. The site must be cleared of trees and brush, should be relatively flat and mowed.

 

Parts for the carts may be 3D printed and assembled by robot. The mirrors may be covered in graphine or gold to minimize deterioration. Electronics must include sensing neighbors, position of target, and a computer, which are common on drones and robots. Each member of the swarm can drive itself to a cleaning station periodically, and to an inspection station for a periodic check up. A maintenance drone might be able to replace a defective wheel without moving the broken mirror cart from service; such service is possible but it may be more practical to haul the defective unit into a maintenance facility.

 

Fixed solar requires access paths between PV or mirrors. A swarm does not; thus, it is possible to save about 30% on land. If one of the swarm is broken, the others can move to make an access path. Solar PV requires between 4 and 6 acres for 1MW. Solar thermal would require about 0.25 acres (10,000 sq ft = 0.1 hectare) of mirror according to http://www.solarmango.com/scp/area-required-for-solar-pv-power-plants/. If each mirror is 10sq ft (1 m ²), the swarm needs 1000 carts. If each cart cost $250, that's $250,000. An acre in my area can cost $250,000.

 

I think this design should be considered by solar thermal engineers.

 

[Ken Fabian]

Interesting idea to have each mirror independent and mobile. It would get down to relative costs and on the face of it they would be more complex and likely to be less reliable which may eat away at any advantage in site preparation and maintenance. Autonomous robotics may be put to better use ... in site preparation and the manufacture and maintenance of permanently placed mirror assemblies.

Edited July 8, 2016 by Ken Fabian

[EdEarl]

It might be possible to have two wheels be coasters, and only one steerable and powered; in which case, a cart would have only three motors, which is less expensive and less maintenance. A fixed mirror would require two motors I think.