Solar power beamed from satellites could provide the UK with a continuous supply of green energy as soon as 2039, according to a report commissioned by the government鈥檚 space agency.
The idea of space-based solar power dates back to and but technology developments and climate change concerns means the concept has seen renewed interest in recent years from China, Japan, the US and, now, the UK.
Preliminary findings of , suggest a 拢16.3 billion development plan could make the concept a reality, and help the UK cut its carbon emissions to meet its binding 2050 net-zero goal.
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The authors of the report, which isn鈥檛 yet officially published, say a network of satellites with solar panels could be launched via rockets into geostationary orbit. Each would weigh around 2000 tonnes and be about 1.7 kilometres across. Once the sun鈥檚 energy is collected by solar panels, it would be converted to high frequency radio waves and beamed down to a 98-square-kilometre antenna facility resembling a giant fishing net to convert it back to electricity.
Martin Soltau of Frazer-Nash, the consultancy behind the report, told on 28 July: 鈥淥ur overall finding is the technology offers new and viable options for the UK to deliver net zero. It makes the cut as a good value investment, where the benefits strongly outweigh the costs.鈥�
Under his possible timeline, a small trial in low Earth orbit in the late 2020s could prove that power can be transmitted back to the ground. This would be followed by an operational power station in 2039. That mooted facility would have a capacity of about 2 gigawatts, 27 times the . The UK has .
Unlike terrestrial solar power, its space-based cousin would be able to provide a continuous source of low-carbon power around the clock. Soltau says that steady supply will be increasingly important in coming years as the UK shifts its energy supplies to more variable sources of electricity, mainly offshore wind farms, to meet its 2050 net-zero goal.
The high price tag and the long time until investors reap rewards means public money is likely to be needed, Frazer-Nash said in its presentation last month. But the group believes electricity beamed from orbit could be financially competitive with other sources of continuous low-carbon power, at about 拢50 per megawatt hour.
In theory, the technology exists to make the concept work. 鈥淭here are no fundamental engineering showstoppers for a demonstration of the entire system at a small scale,鈥� says Leopold Summerer at the European Space Agency. On 17 August, the Chinese government to have broken ground on a facility for space-based solar power in the city of Chongqing.
Nonetheless, Soltau acknowledges there remain major obstacles for the UK. Those include the size of the area needed for the antenna 鈥� a challenge in a crowded island like the UK, meaning it could be sited offshore 鈥� regulatory issues over the radio frequency needed for the energy transfer, and the need for cheap and regular rocket launches.
There is also the potential showstopping issue of the environmental impact of the number of rocket launches needed to establish the solar arrays almost 36,000 kilometres off the ground. Soltau says establishing 25 solar power satellites over 10 years would require near daily launches by a rocket akin to SpaceX鈥檚 Starship, which . Billionaires Richard Branson and Jeff Bezos have both come in for criticism for the climate impact of their recent private space flights.
鈥淭here鈥檚 no point in trying to see if it鈥檚 technically achievable when the very reason you鈥檙e creating the thing in the first place [net zero] is going to be null and void,鈥� says at the University of Strathclyde in the UK. 鈥淚f you consider the entire life cycle of the concept it actually requires quite a considerable environmental footprint. It is borderline greenwashing,鈥� he says of the idea of solar-based solar power.
Wilson, who is chair of the environment working group of the UK Space Energy Initiative, that life-cycle emissions from rocket launches and the concrete and steel involved in the antenna means space solar would have lower CO2 emissions per unit of energy than coal, oil and gas, though higher than from terrestrial renewables.
Soltau notes that Wilson鈥檚 study looked at 40-year-old technologies, which have seen significant developments that would cut CO2 emissions. For example, the weight of solar power satellites has gone from 20,000 tonnes in 1970 to 2000 tonnes now, he says. 鈥淚t seems likely that a new environmental impact study would find strongly in favour of the current generation of solar power satellites,鈥� he says.
Still, of University College London says the plan sounds very speculative. 鈥淚t is worth supporting some research on it, but very much as an exploratory science project rather than a practical option to help meet net zero by 2050,鈥� he says.
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