Over the years, solar energy has made great strides. In the U.S., utility-scale solar project developers have negotiated sales agreements to utilities at prices averaging 5 cents/kWh, the Lawrence Berkeley National Laboratory reported in September. And installed project costs have dropped more than 50% since 2009.
But for all the technological advances made, there’s one thing that can’t be controlled by man: the whims of the weather.
Jean-François Guillemoles, the director of the French National Center for Scientific Research and the French director for NextPV, wants to change that. Not the weather, but how we collect solar energy. The answer: balloons.
“What if, instead of waiting for sunlight to reach solar panels on the ground, balloons were used to capture solar energy up in the air, where space is not restricted, where yields would be multiplied and clouds would never interrupt production?” he muses in a post.
The French-Japanese laboratory NextPV is looking into the idea by studying lightweight polymers.
According to Huffpost Science, the balloons would be equipped with generators and tethered to the ground.
“There are very few clouds at an altitude of 6 km—and none at all at 20 km,” he writes. “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. Under these conditions, the energy source is five times more abundant than on the ground.”
The idea isn’t as far-fetched as it sounds. Already, Google has tested Internet balloons at heights of 20 km.
In the proposal, excess solar energy captured by the balloon would be sent into a fuel cell, which converts the current into hydrogen through water electrolysis to keep the balloon floating. At night, the fuel cell recovers the hydrogen, which mixes with oxygen and produces water and an electric current.
“Such a solar generator would be very easy and fast to install as well as to move or remove when required,” Guillemoles told Fast Company. “And, land use is minimal. It has the potential to make solar energy more sustainable and faster to deploy at large scale.”