Solar panels will be vital to powering the world in the future, but what will we do on days when the clouds block the sun’s rays? Energy scientists from France’s CNRS and the University of Tokyo are looking towards balloons for the answer. The scientists are developing solar panels attached to high-altitude balloons that would hypothetically float 20 kilometers above the ground, far beyond where most clouds reside. At that altitude, the direct illumination is five times more intense than on Earth, resulting in more effective energy conversion. One of the greatest appeals of these balloons is that they would be filled using hydrogen, and would be able to use that same hydrogen to store about 10 days equivalent of its own solar electricity production. Structural and installation costs have yet to be seen, but high-flying solar balloons could just provide another efficient alternative for renewable energy production.