Probably the most efficient way of harnessing solar power is by using Concentrated Solar Power plants, or CSPs. Their design, however, is based on large mirrors (heliostats) placed in rows around a central tower, onto which they reflect the sun’s energy.
These heliostats are placed in an expanding formation, the mirror in the back being placed between the two mirrors in front. The primary resources used by these plants to generate power are sunlight and land. This makes the current designs inefficient, because this arrangement increases the amount of shadowing throughout the day and it also uses a lot of space.
So, one trick of increasing the efficiency of such a design is to reduce the amount of land needed, while at the same time increasing the amount of sunlight that the mirrors can collect.
Researchers at MIT, along with their colleagues from RWTH Aachen University in Germany, have come up with an improved design, that does just that.
After thorough calculations, they realized that they could reduce the land needed by bringing the heliostats closer together, without affecting the sunlight reflecting efficiency. Turning out to be a similar pattern to those found in nature, the new spiral shaped layout lead the scientists to look at more of mother nature’s examples, and especially the sunflower.
The sunflower petals are arranged in a spiral pattern, being turned at an 137 degrees angle from one another. Thanks to this pattern, known as a Fermat Spiral, the scientist were able to reduce the land mass required up to 20% and increase the efficiency of sunlight reflection while at the same time reducing the number of heliostats needed.
Needing huge areas and representing up to a third of the total costs of a CSP, great care must be taken in the placement of this heliostat field. So, as Mitos says “If we’re talking about going to 100 percent or even 10 percent renewables, we will need huge areas, so we better use them efficiently.”
Dramatically reducing the required space without affecting the amount of energy gained, this new design is an important breakthrough.