Solar Balloons Above the Clouds Are Crazy Efficient

Engineers are building solar balloons that float above the clouds for constant sun

By Chloe Olewitz December 17, 2015

Solar farms have been making headlines lately, and solar power options are gaining in popularity as their efficiency levels improve. But a new photovoltaic solution is going to bring solar farms directly to the skies in order to supercharge that efficiency. Since cloud coverage creates uncertainty around the effectiveness of solar farms, why not bring the solar cells themselves above the clouds? Using stratospheric balloons, it may be possible to source solar power from the open skies without any kind of environmental interference.

An international consortium is working on the idea, under the direction of French-Japanese scientific research lab, NEXTPV. The main tenet of the concept is that there are very few clouds floating around at an altitude of about 3.7 miles (6 kilometers). At an altitude of approximately 12.4 miles (20 kilometers), there is no cloud interference at all. Eliminating cloud coverage and light diffusion that occurs in the many close layers of the Earth’s atmosphere leads to a higher concentration of sunlight. In turn, this concentrated solar power leads to higher energy yields from photovoltaic solar cells.

Hydrogen is the other key factor in the plan to make this sustainable idea a reality. The logistical plans that describe launching these huge solar cell balloons into the sky also require a strategy for keeping them afloat. These floating solar farms would use the excess electricity generated during the daylight hours to recombine hydrogen and oxygen in a fuel cell. That fuel cell would release power regularly or as needed overnight. And the same source of hydrogen isolated through water electrolysis for the fuel cell would keep the balloons in the air.

The solution keeps costs low, and its only byproduct is pure water molecules. The balloons would be made of low-energy polymers, which are easy to mass-produce. Initiatives like Google’s Project Loon are already making use of the same conceptual balloon approach. The consortium of researchers and scientists hopes that the low cost of the solution and the space-saving approach will make solar farms more plausible in the future. As it stands, functional solar farms and renewable energy plants take up enormous amounts of space on land. That’s one thing in the desert, but it’s another issue entirely in a city like Paris, London, or New York.

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