Space-based solar power infographic
Graphic shows proposed SPS-Alpha space-based solar power station.


The Sun never sets in space

By Duncan Mil

May 12, 2022 - Solar Power Satellites (SPSs) will collect the Sun’s energy and beam it securely to a fixed point on Earth. Each SPS can generate more than three gigawatts (GW) of electricity.

One significant barrier to the uptake of renewable energy technologies is that they don’t provide a constant energy supply. Wind and solar farms only produce energy when the wind blows, or the Sun shines. One possible solution would be to capture solar power in space.

Averaged over the entire planet, the amount of sunlight arriving at the top of Earth’s atmosphere is approximately 340 watts per square metre. In addition, typical panels collect light just 29 per cent of the time due to day and night cycles, positioning, and weather.

If we could place solar panels in Geostationary Earth Orbit (GEO is 35,786km from Earth), the incident sunlight would reach 1,358 watts per square metre.

A single solar power station such as the SPS-Alpha may have to cover 28 million square metres -- equivalent to 3,920 football pitches. Using lightweight modular units will also be critical, as the most significant expense will be the cost of launching the station into space. The modular design also means robots can assemble the satellite in GEO.

The SPS-Alpha, designed by American John Mankins, would convert electricity from the solar panels into microwave energy and beam it to an antenna on the Earth’s surface.

The antenna would then convert the waves back into electricity. SPS-Alpha would supply two gigawatts of power to the Earth’s grid -- the equivalent of a nuclear power station. To produce that much power with solar panels on Earth, you need more than six million.

Solar power stations in space will likely become a reality within decades.

PUBLISHED: 12/05/2022; STORY: Graphic News