Power plants in space sound like a science fiction idea – and it really is a science fiction idea: 1941 story by Isaac Asimov reason described a space station that transmits energy collected from the sun to other planets using microwave rays. Today the technology is in place and space-based solar power (SBSP) is being taken seriously.
The idea is that a huge, kilometer-long satellite generates electricity via thousands of photovoltaic panels. These would then be transmitted to Earth using high-frequency radio waves. On the ground, this beam of microwave energy would be intercepted by an array of elliptical radio antennas, converted into electricity and distributed to the grid.
But is that really a realistic perspective?
Brian Ryan, vice president of innovation at National Grid, admits people think he’s “crazy” when he talks about it. “It’s a little bit out there,” he says, “but it’s not that far out there. I think we will see space-based solar power play a huge role in our energy ecosystem over the next 20 years… The potential is unlimited.”
A report for the UK government released last year by engineering firm Frazer-Nash described SBSP as “technically feasible” and potentially affordable compared to other clean power sources. The US also believes SBSP technology is worth investigating: a military project is underway, as is one at the world-renowned California Institute of Technology. The Japanese space agency is working on a space solar farm. China reportedly intends to open its first station by 2035 and has already started construction in the city of Chongqing.
Why is it considered a good idea?
SBSP could potentially solve various tricky energy problems. It is estimated that global energy needs will double by 2050 and sources that do not use fossil fuels or come from objectionable regimes are being sought. Plenty of clean power is available in space: a narrow swath around the Earth could supply more than 100 times humanity’s projected global energy needs by 2050, the Frazer-Nash report found.
Unlike renewable energy sources on our planet’s surface, SBSP would not be intermittent. It’s always sunny in space, and power plants would be in high geostationary orbit—that is, staying in a fixed position relative to Earth—and supplying electricity almost continuously. This would mean both more energy in absolute terms and SBSP’s ability to provide base-load power – the minimum amount of electrical energy the grid requires at any given time. Currently, renewable sources cannot provide base load electricity; Only fossil fuels and nuclear power plants can do that. Finally, SBSP could be beamed to different parts of the world as needed.
How much energy could there be?
Prototype designs for SBSP stations envisage each sending at least one gigawatt of power to Earth. One gigawatt is enough to supply around 750,000 households with electricity and is comparable to the output of a nuclear power plant. John Mankins, a former NASA scientist and leading expert on SBSP, believes his design would generate three gigawatts, but that one gigawatt would be lost in radiating back to Earth.
Wouldn’t that be very expensive?
Yes, the main costs are the need for multiple rocket launches to launch the components into space and the robotic assembly of the SBSP station in orbit. A solar satellite would have to be “an order of magnitude larger in mass and extent than any spacecraft currently in orbit,” the Frazer-Nash report concedes.
Nevertheless, the costs for space missions have fallen massively in recent years. According to a NASA study from 2018, it had fallen by a factor of 20 in the previous ten years. Frazer-Nash estimates that it would cost around £16 billion to develop the technology and launch an operational solar satellite – much less than the £23 billion expected cost of the proposed Hinkley Point C nuclear power plant.
Is everyone convinced?
no In 2012, Elon Musk – who runs both a solar energy and space company – called SBSP “the dumbest thing ever.” And it certainly has its downsides. The technology used has not yet been tested on a large scale. Getting into space is only part of the problem. Once built, it would be vulnerable to damage from space debris. Repairs would be extraordinarily difficult to carry out. Antenna receiving stations on Earth would require large areas of land and would likely be controversial.
SBSP would have to compete with regular solar power, which is the cheapest form of power in history today. There are also security concerns, and given the sensitivities of rival superpowers over control of space, this would require extensive international cooperation.
So will it happen?
In March, UK Science Secretary George Freeman said SBSP was “taken seriously” by the government. “We’re ready to be bold,” he said, and ready to “support that.” In the short term, however, SBSP will likely remain limited to specific areas such as military use.
One of the most advanced projects is the US Air Force Research Laboratory’s Arachne Project, which is scheduled to start in 2025. It aims to show that the technology works and that it could be used to send power to relay military bases (power supply is often one of the most dangerous parts of a ground operation due to the involvement of vulnerable convoys or supply lines).
Arachne will also explore the possibility of using an SBSP station to power interplanetary spacecraft. The Air Force Research Laboratory points out similarities to GPS, which was originally used as a military tool but is now used with great success by civilians everywhere, every day.
https://www.theweek.co.uk/news/science-health/956519/power-stations-in-space-sbsp-explained Power plants in space: How to take this sci-fi concept “seriously”.