Scientists at MIT and RWTH Aachen University may have revolutionized the effectiveness of concentrated solar plants – by emulating the pattern found on a sunflower, otherwise known in science as Fermat’s spiral. By rearranging the CSP’s massive heliostats, or mirrors, to resemble the yellow flower’s petals, the solar power harvester can take up 20% less space. Making the system more compact increases the CSP’s efficacy, giving it a higher potential for energy generation.
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A traditional CSP plant, like PS10 in Spain, can generate enough solar energy to power 6,000 homes. But the drawback is the sprawling space needed to install the hundreds of almost 40 foot mirrors that siphon the power of the sun. As the sun moves throughout the day, the mirrors track it, and transfer the power to a central tower that rises over 300 feet. The process is effective, producing ample amounts of clean energy, but limits where it can be located due to the space needed.
Because the huge mirrors can cast shadows on each other, rendering them temporarily useless, a new pattern was needed to maximize effectiveness. From ancient Greeks to mathematicians, the “golden angle” of the sunflower, or 137 degrees, has been long respected, and researchers noticed the pattern could be used to optimize solar plants.
Using the magic 137 degrees to arrange and angle the helistat mirrors, the CSPs took up 20 percent less space, and also have reduced shading and blocking! The reduced land space and increased effectiveness means that CSPs can be installed in more and more areas of the world, creating potential for green energy to be produced.
Via Science Daily
Images ©Wikimedia Commons
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Once again, nature >> humans
The barrier to competitiveness of solar thermal has never been land space; it’s cost. 20% less land usage probably results in less than 1% (or even 0.1%) cost savings. Land is expensive in Spain, where the pictured plant is located, however the solar resource is terrible in Spain compared to other places (where land is dirt cheap, literally). The only reason companies have built there is because Spain “had” a ridiculous subsidy: something like 30 euro-cents per kWh! Compare that to my electricity cost here in CA of about 8 us-cents. Cheaper heliostats and higher cycle efficiency is where it’s at.