They look like foil party balloons, but they are actually very efficient solar concentrators. These solar “balloons” were developed by a company called Cool Earth, based in California, and it has just received $21 million dollars in investor funding. The company is now planning to build a 10-megawatt plant of solar balloons in the next couple years. This power plant would be comprised of 10,000 balloons, and cover roughly 80 acres!
So what exactly are these solar balloons? One half of the solar balloon is reflective mylar, the other side is clear film. The balloons are lightweight and easy to string up but rugged enough to withstand 100 mph winds, according to the company. The delicate photovoltaic technology is protected inside the balloon.
The company says:
Our system works like a conventional concentrated photovoltaic cell (CPV) system, but we are unconventional in our mechanical approach to forming and pointing our mirrors. Instead of rigid aluminum or glass structure to focus light, we use metalized plastic films and instead of ribs, trusswork, or material heft to maintain the mirror shape, we use active inflation air.
Unlike most other CPV companies, we actively water cool our photovoltaic cells to remove waste heat rather than relying on large, material intensive, heat spreaders and sinks.
You can read Cool Earth’s FAQ about the balloons here.