Perhaps we shouldn’t be surprised that the fast-growing, brilliantly bright sunflower offers guidance on how best to gather solar energy. Researchers from MIT and RWTH Aachen University in Germany recognized that possibility, and they ran with it. They’re reporting now that by mimicking the spiral pattern of the sunflower in laying out the heliostats in power tower concentrating solar power (CSP) plants, they can reduce both the amount of land and the number of heliostats needed.
Power tower CSP plants use big mirrors – heliostats – to direct sunlight at the top of a tower several hundred feet high. The energy is received by the tower and used to heat water, generating steam and then power. There are plants like this already operating in Europe and several are either under construction or planned for construction in the United States, including some that use molten salts to store the heat that’s been gathered so it can be used to produce power long after the sun goes down.
The researchers used the first power tower plant ever built, Abengoa’s PS10 in Andalucia, Spain, as the model for their theoretical work as they sought to find ways to optimize the heliostat layout to improve efficiency. Some initial efforts to squeeze the mirrors together yielded encouraging results; the amount of land the mirrors took up was trimmed by 10 percent without degrading the efficiency of the mirrors. And the researchers noted something interesting about the resulting pattern: It had some spiral elements similar to layouts in nature. That’s when the sunflower-shaped light bulb went off.