Solar Power Towers: The Ultimate in Utility Scale Solar Energy
What is that? What the fuck is it, right? Doomsday weapon? Observatory? No, it's a solar power plant. Those aren't solar panels either, but thousands of mirrors on motorized, pivoting mounts. The mirrors focus sunlight onto the tip of the tower, heating it up to boil water, which then drives a steam turbine.
Besides looking like something out of a science fiction film, solar power towers leverage the benefits of solar energy while avoiding the relatively high cost of photovoltaic panels and batteries. Photovoltaic panels have come down quite a lot, but batteries are still terribly expensive, and solar power towers have no need of them.
How can that be, you think. How can it store energy without using batteries? Since the energy generated is heat, why not store it as heat? That cuts out a lossy conversion step. There is a secondary chamber around the water boiler which contains not water, but molten salt. As it turns out, salt is extremely efficient at retaining heat.
A set of pumps circulate molten salt from the holding tanks at the base of the tower up into the chamber where it's heated by the focused sunlight. After the sun goes down, the stored up heat continues to boil water, generating electricity. Some towers include sufficient molten salt storage for up to 14 hours of after-dark operation.
The result is a means of generating energy from sunlight which, on very large scales, is more efficient and economical than just using loads of photovoltatic panels. Of course solar panels remain the right choice for the roof of your home, as you can't exactly fit a solar power tower up there. They aren't going away any time soon, just being relegated to applications that require either portability or where there isn't enough space for all the mirrors that a solar tower requires.
What say you? Is this the way to a brighter future? Or are there compelling reasons why we shouldn't give over desert land to projects like this? If you weigh the importance of increasing clean energy generation to fight climate change against loss of habitat for desert dwelling species, in the long run, which is more important?
More projects like this!
I remember watching a documentary about the solar power plants using concentrating solar towers as being an efficient alternative to only using solar power panels, it is interesting stuff. If I remember correctly the one on the first photo was somewhere in Spain?
Yes, the PS10.
where there's molten salt, there could also be a thorium reactor :) 2 birds, 1 stone.
I've been under the impression for quite a while that some iteration of the sun furnace concept would be vastly superior to the photovoltaic panels which are comparatively expensive to produce in terms of raw material footprint.
Except if we choose to make the deserts green farmland again, building a few of these should be a rational and logical use of desert space - with enough room left for desert-dwelling ecosystems.