The energy storage system is planned to involve a combination of solar PV panels, hydrogen production and fuel cells, which are to be placed as solar balloons above the clouds enabling solar PV to continue generating power even when it is cloudy.
NextPV lab co-director and senior researcher, Jean-Francois Guillemoles, said: “The main problem with photovoltaic energy is that sunlight can be obscured by clouds, which makes electrical production intermittent and uncertain. "But above the cloud cover, the sun shines all day, every day.” Guillemoles furthered explained that: “Anywhere above the planet, there are very few clouds at an altitude of 6km—and none at all at 20km.
"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 colour, direct illumination becomes more intense: the concentration of solar energy results in more effective conversion, and hence higher yields.”
It's an interesting concept, and one that we might well have to utilise in the future for areas that see a lot of cloud cover. One of the biggest obstacles here is ensuring they don't coincide with flight paths; after-all these would essentially be the rocks of the sky.