Harnessing the sun’s energy for use here on Earth is a fairly easy thing to do in areas where a lot of sunlight hits the ground (or rooftop, as it were). New developments in solar power technology are working to maximize energy conversion, from capturing as much sunlight as possible to increasing the amount of energy converted. But no solar panel on Earth can do what NextPV is hoping to achieve. The research group is aiming to capture solar energy in the one place where the sun is shining virtually all the time: above the clouds. They say solar balloons floating above the clouds could create high-flying solar farms capable of producing clean energy around the clock.
When it comes to solar power, there are a few images that typically come to mind. Solar panels on the rooftop of a private home, a ‘solar farm’ on the ground with rows of tilted panels, or perhaps one thinks of a solar-powered vehicle like a desert racer or electric airplane. Some companies, like Google, have indeed already created solar-powered balloons – but not for the express purpose of generating electricity to use on the ground. NextPV, which is a partnership between the French National Center for Scientific Research and the University of Tokyo, has been focused on doing just that.
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It’s not as simple as connecting photovoltaic panels to a weather balloon and sending it into the sky. The researchers explain how their solar balloons will directly convert sunlight to electricity during the day, and then produce hydrogen, which works as an energy storage medium for producing electricity in a fuel cell, at night. Essentially, this means the balloons could be generating electricity around the clock, and because of their position at least 3.7 miles above the Earth’s surface, there will be no clouds to interfere with their efficiency.
Right now, solar balloons like this are only a concept, but researchers working on the project believe the potential for clean energy generation is enormous – especially if groups of the balloons are floated together in a network like a big solar farm in the sky. NextPV believes chasing after sunlight above the clouds is a vastly more efficient means of harnessing solar energy. “Anywhere above the planet, there are very few clouds at an altitude of 6 km (3.7 miles)—and none at all at 20 km (12.4 miles),” says Jean-François Guillemoles, CNRS senior researcher and the French director of NextPV. “At those heights, the light comes directly from the Sun, as there are no shadows and hardly any diffusion by the atmosphere. As the sky loses its blue color, direct illumination becomes more intense: the concentration of solar energy results in more effective conversion, and hence higher yields.”
We’ll be watching this technology closely for developments as the team aims to build a working prototype in the next two years.
Images via PixScience.fr/Grégoire CIRADE for CNRS