Space Based Solar Power: Like Terrestrial Solar, but More Expensive

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Essay by Eric Worrall

“… we think we can build and commission a 2GW power station every year. …”

Space-based solar power: How it works, and why it’s being considered now

ABC Science / By technology reporter James Purtill

It’s an idea that sprang from mid-century science fiction and was being seriously considered in the 1970s, in the golden years of space flight.

Key points:

Space-based solar power involves beaming clean energy to Earth from orbital solar farms
If it works, it could supply non-intermittent renewable electricity 
But the technology is unproven and may end up costing more than projected

Space-based solar power (SBSP) was eventually dismissed as too expensive, and consigned to the attic of Space Age fantasies, along with lunar bases and ray guns.

Now, it’s back. Space agencies are returning to the idea of constructing enormous orbital arrays of solar panels, then beaming the power to Earth via microwaves.

Putting solar panels in space may seem unnecessary (when there’s still room on our roofs), but this vision of the future has powerful backers.

Millions of dollars are being ploughed into the concept of vast photovoltaic “islands in the sky”.

Martin Soltau is an analyst at Frazer-Nash Consultancy and co-chair of the UK’s Space Energy Initiative, which is a consortium of companies, universities and government helping to develop SBSP.

solar power station at the “gigawatt scale” is achievable within 12 years, he says.

“After that … we think we can build and commission a 2GW power station every year.“

A cost-benefit analysis commissioned by the ESA calculated the average cost of electricity generation by SPSP over the lifetime of a generator unit, including construction, maintenance and decommissioning.

It arrived at a figure of 0.038-0.106 euros per kilowatt-hour by 2045 ($0.059-$0.16 per kWh).

By comparison, Dr White says, ground-based solar has a cost of around 0.03 euros per kWh — and falling.

The figure doesn’t take into account the need for storage, but “the cost of storage is also coming down rapidly.”

Dr. White’s squirming over the cost of terrestrial solar + energy storage is amusing.

The fact space based solar is apparently being seriously considered, and the emphasis on the fact space based solar is not weather dependent, in my opinion is a rare glimpse of the dire state of the terrestrial green energy push.

Even some of our more numerically challenged green politicians are starting to realise that renewables are more hype than potential, that the intermittency and unreliability of terrestrial renewable energy is a showstopper.

Of course, space based solar is not without its problems. Space experiences its own “weather”, in the form of solar storms, blasts of radiation which can damage fragile electronics.

Low Earth orbit is suffused with corrosive monatomic oxygen blasted off the top of the Earth’s atmosphere by solar radiation. Chemical erosion may be less of an issue if lots of money is spent to boost the solar power satellites into geostationary orbits, but the radiation can be worse in higher orbits. Geostationary orbit (22,236 miles) is inside the Van Allen radiation belt (400-36,040 miles), a region of space where the Earth’s magnetic field traps energetic, electrically charged radiation which can wreak havoc on sensitive electronics.



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