One small step for space based solar power

United KingdomScotland

On 27 September, 2021, the Department for Business, Energy & Industrial Strategy (“BEIS”) published an independent report titled “Space Based Solar Power: De-risking the pathway to Net Zero”. The report concludes that space solar power (“SBSP”) is technically feasible, affordable- though requiring very high initial investment- and could bring significant benefits to the UK economy. It notes, however, that the technology is in its infancy.


The UK Government has committed to bring all greenhouse gas emissions to net zero by 2050. To reach this goal, it is exploring a number of renewable energy sources including solar, offshore and onshore wind (more information on this can be read in our contribution to The Renewable Energy Law Review). The report, which was commissioned in November 2020, was created in collaboration with Frazer-Nash Consultancy, and explores the potential utility of space based solar power (SBSP) in helping the UK reach net zero.

The Technology

Space Based Solar Power is a conceptual technology that involves locating solar panels in the Earth’s Geostationary Orbit and beaming energy back to terrestrial rectifying antenna (rectenna). In theory, far greater amounts of energy can be captured using this method than ground-based solar. The sun would shine directly on the satellites, unaffected by the Earth’s atmosphere, inclement weather or diurnal cycles.

The report envisages solar satellites on kilometre scale capable of generating 3 Gigawatts (GW) of electricity per satellite. This energy would be returned to earth via wireless transmission at a frequency of 1-10GHz. The rectenna would convert the radio waves into around 2GW of electricity- the equivalent capacity of single nuclear power station. In its assessment of feasibility of technology, cost, and potential electricity output, the report focuses on two satellite designs: the SPS Alpha (designed by John Mankins, USA) and CASSIOPeiA (designed by Ian Cash, UK).

The Risks and Rewards

  • The report estimates space solar panels would be illuminated by the sun for 99% of its orbit. As satellites will be generating electricity almost constantly, compared to the intermittent nature of UK based solar energy, it can be used as a clean source of baseload electricity.
  • The report estimates the Levelised Cost of Electricity (“LCOE”) to be £50/MWh. You can see how the LCOE compares to other energy sources in the graph below. However, it clearly carries more risk than conventional earth based generating technologies for which an investment hurdle rate of 20% has been mooted in the report. The report points out that, as technology matures, the risks should go down, further lowering the LCOE.

  • The proposed technology has not yet been developed and exists only as a concept. While other countries, notably China and Japan, are already exploring SBSP to generate electricity, only kW scale wireless power transmission has so far been achieved. At present, the cost of sending material to space is expensive, though costs have been reducing over time, a trend which is predicted to accelerate as commercial space transportation ramps up.
  • As with any new technology, there are high development costs. The report estimates these to be £16.3 billion in total. These costs would be met by public sector funding initially, until there is sufficient confidence to enable private sector engagement. The report suggests Phase 1 (please see figure below) would cost £350 million over five years.
  • The report lists a number of other potential benefits, including: the eventual ability to export energy directly to other countries; the skills that will be developed as a result of the project; and, the improvements that will be brought to areas of technology such as photovoltaics and wireless power transmission.

Recommendations and Next Steps

The report recommends integrating space based solar power into UK Government strategies for reaching net zero. It suggests further concept design studies should be carried out and recommends engagement with the energy market. The principal focus of the report was on technical and economic aspects. It recommends further study into topics including grid integration, environmental impact, and security risks.

A provisional project timeline proposes ground and balloon-based trials by 2026 and small capacity low earth orbit satellites to be trialled by 2031 with the technology and capacity being scaled up over time. Ultimately, the report concludes that a substantial portion, around 15%, of the UK’s energy requirements could be met from SBSP by the early 2040s.

The report is available to read here and the accompanying economic and feasibility reports can be found here.

Diagram demonstrating the proposed phases of the UK’s development of Space Based Solar Power.


Space Based Solar Power is an ambitious concept that is still many years away from development. The major hurdle will likely be the use of public money for untested technology. The public and private sector have both shown appetite for investing in novel energy generation solutions but the technology proposed in the report is several orders of magnitude more challenging in terms of complexity, initial cost and risk.

Should the technology come to fruition, it could fundamentally change the energy market. SBSP generators would be able to transmit their energy to any point on Earth- and able to sell their energy to the highest bidder- unless there are strict, internationally recognised regulations. It may be feasible to transmit power directly to consumers, thereby circumventing the distribution network. The reliability of solar beyond the Earth’s atmosphere may reduce the volatility of energy prices to Earth based fundamentals such as global gas prices or low wind environments etc.

Article co-authored by Sandy McDougall