Space-based solar power

Solar energy generation has grown far cheaper and more efficient in recent years, but no matter how much technology advances, fundamental limitations will always remain: solar panels can only generate power during the daytime, and much of the sunlight is absorbed by the atmosphere during its journey to the ground. What if instead we could collect solar power up in space and beam it down to the surface? ESA is seeking ideas for technologies and concepts for solar power satellites that will do precisely this.

Incident solar radiation
In orbit, the intensity of sunlight is much higher than the intensity at Earth’s surface.

Sunlight capture and energy regulation
Sunlight is converted into a current, then prepared for radio frequency beaming to Earth, the Moon or another planetary surface.

Power beaming
Energy is sent down to Earth using phased arrays, laser emitters or other wireless technologies. The energy beam must be accurate, reliable and should retain as much of its power as possible as it travels through Earth’s atmosphere.

Beam capture and energy conversion
The energy beam is captured with photovoltaic cells or with an antenna that converts electromagnetic energy into electricity. Satellites can beam energy down to a single ground site, or to several locations around a planetary object.

Power transmission
Systems that collect the space-based solar power on Earth must be safely and sustainably integrated into existing power grids. Power distribution is also vital in science, exploration and colonisation missions.

Energy utilisation
As well as having the potential to aid Europe’s goal of becoming carbon neutral by 2050, space-based solar power technologies could provide the flexibility and reliability required for science and exploration missions where other power sources are limited, for example rover missions during the lunar night.