From Watts Up With That?

Essay by Eric Worrall

University of Glasgow academic Onur Çelik has proposed huge space mirrors could allow solar panels to satisfy electricity demand in the morning and after sundown.

Reflectors in space could make solar farms on Earth work for longer every day

Published: January 12, 2024 4.24am AEDT
Onur Çelik
Postdoctoral Research Associate in Space Technology, University of Glasgow

If you happened to be looking at the sky in Europe on a cold night on February 5 1993, there is a chance you could have seen a dim flash of light. That flash came from a Russian space mirror experiment called Znamya-2. 

Znamya-2 was a 20-metre reflective structure much like aluminium foil (Znamya means “banner” in Russian), unfurled from a spacecraft which had just undocked from the Russian Mir space station. Its goal was to demonstrate solar energy could be reflected from space to Earth.

This was the first and only time that a mirror had ever been launched into space for that purpose. But, three decades on, colleagues and I believe it’s time to revisit this technology.

Unlike proposals to build solar power stations in space and transmit energy down to earth, all the generation would still happen down here. Crucially, these reflectors could help solar farms generate electricity even when direct sunlight is not available, especially during evening and early morning hours when demand for clean energy is greatest. Colleagues and I call this concept “orbiting solar reflectors”.

…Read more: https://theconversation.com/reflectors-in-space-could-make-solar-farms-on-earth-work-for-longer-every-day-220554

The following is a video of the concept;

Technically this seems feasible – but at what cost? Solar energy is already absurdly expensive. Adding large space structures might reduce battery backup requirements, but it still seems hideously expensive.

There is also a crucial difference between orbital solar panels and orbital mirrors – orbital panels could still transmit power to the ground when the weather is overcast.

Microwaves from an orbital solar power station can penetrate cloud cover, reflected sunlight not so much – unless there is enough concentrated sunlight to burn away the cloud cover.