Sunflower-Inspired Pattern Could Boost Concentrated Solar Power Efficiencies

Arranging heliostats at certain angles could reduce land footprints for big solar plants

2 min read
Sunflower-Inspired Pattern Could Boost Concentrated Solar Power Efficiencies

New research from MIT and RWTH Aachen University in Germany joins a growing list of biomimetic concepts—from whale-inspired wind turbines to artificial photosynthesis—that are helping renewable energy push forward. This time, the researchers copied a seemingly appropriate source to boost the efficiencies of concentrating solar power (CSP) technology: the sunflower.

The florets on the face of a sunflower are arranged in what is known as a Fermat's spiral, with each individual floret sitting at approximately a 137-degree angle to the one next to it. The researchers, led by Corey Noone of MIT, found that arranging mirrors—or heliostats—that sit around a central tower at such angles to each other

yield big improvements in CSP output. An existing field, the PS10 plant in southern Spain (pictured above), would gain 0.36 percent in efficiency while also reducing its land footprint by 15.8 percent. They note in their paper, published in the journal Solar Energy, that "the improvement in area becomes more pronounced with an increased number of heliostats." The improvements come from an increase in the amount of sunlight that hits each mirror and decreases in shading and blocking from the heliostats around it.

“Concentrated solar thermal energy needs huge areas,” said senior author Alexander Mitsos in a press release. “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.”

CSP has not taken hold in a big way yet, but some of the largest solar projects in the world are using such technology. Construction is under way in the Mojave Desert, for example, on Brightsource Energy's Ivanpah Solar Electric Generating System. The 392-megawatt facility will cover 3,600 acres of land, and with continuing objections regarding public land use and concerns over native flora and fauna, reducing land footprints for such projects is a noble goal.

(Images via afloresm and lucapost)

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This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

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