SBSP Graphic

The Space Energy Initiative will bring together government, research and industry in the space and energy sectors to develop and deliver a co-ordinated programme of technology development and demonstration.

Meeting the timeline set out by the Government’s Net Zero pledge, and in partnership with other nations, the aim is to establish the first orbital demonstrator SBSP system by 2030, with the first of a kind operational system delivering power into the grid by 2040.

A constellation of Solar Power Satellites would be in operation by the mid 2040s, delivering a substantial proportion of the UK’s energy needs.

What is Space Based Solar Power?

Space Based Solar Power is the concept of harvesting solar energy in space, and beaming it to earth, thereby overcoming the intermittency of terrestrial renewable energy.

The benefits it offers include clean, continuous base-load energy, with much lower land usage than conventional renewables. It could provide a substantial percentage of the UK’s energy needs in future, as part of a mix of energy technologies.

Solar Power Satellite designs are well advanced in several nations and the UK Government has confirmed the engineering feasibility of the concept through an independent study.

A typical system comprises a constellation of massive, kilometre scale satellites in GEO. Each has very lightweight solar panels and a system of mirrors to concentrate sunlight onto the panels, generating around 3.4 GW of electricity on the satellite. This is converted into RF microwave radiation, with an efficiency of 85%. The microwave frequency proposed is typically 2.45GHz to be transparent to the atmosphere and moisture, and a net 2.9 GW of power is beamed to a receiving antenna at a fixed point on the ground below.

A secure pilot beam is transmitted from the ground to the satellite to allow the microwave beam to lock onto the correct point. The ground rectifying antenna or ‘rectenna’ converts the electromagnetic energy into direct current electricity and then through an inverter which delivers a net 2 GW of AC power into the grid.

London Array FN

The picture above shows the comparative size of an SBSP rectenna delivering a continuous 2GW, with the London Array Wind Farm with a maximum rating of 630MW. Siting rectennas offshore and taking advantage of existing grid connections may be an attractive option.
Image © Frazer-Nash Consultancy

The angle between the solar collector and the microwave transmitter is constantly changing as the earth rotates. Thus if the mirrors are always pointed towards the sun, the microwave beam is steered to always point at the correct location on the earth. In this way the system can deliver full power levels day and night, in all weathers, and all year round.

The intensity of the microwave beam is around 240 W/m2, which is about one quarter of the intensity of mid-day sunlight. So the system cannot be used as a beam weapon, nor is it harmful to life on earth.

The Solar Power Satellite (SPS) weighs several thousand tonnes, and the specific power in kW per kg is a key parameter for estimating both the cost of hardware and its deployment into GEO. Estimates for leading SPS designs independently calculate the Levelised Cost of Electricity (LCOE) at less than £5 per MWh.

Enablers and Challenges

SBSP is challenging because of the sheer scale of infrastructure being deployed in space. Many of the underlying technologies are considered relatively mature, and the physics of power collection and beaming is well understood. The reducing cost of space launch is making the concept increasingly affordable, and the latest modular SPS concepts are designed for industrial scale manufacture and robotic assembly. These attributes are key to achieving a competitive LCOE.​

Energy Generation

  • Continuous power generation, 24/7, 365 days/year
  • Gigawatt levels of base-load energy generation
  • Green hydrogen generation for the transport sector

Environmental Impact

  • Fully sustainable, renewable energy source
  • Zero carbon,carbon payback period <12 months
  • Low environmental impact (footprint, land use)

Security and Economics

  • Security and resilience to political or terrorist action
  • Affordable LCOE for homes and industry
  • Long term security of fuel supply (5 Billion years)

Delivering Net Zero

  • Roadmap for orbital demonstrator by 2030
  • Operational system could be developed by 2040
  • Scalable to provide substantial proportion of energy

Grid Integration

  • Readily integrated with Grid infrastructure
  • Low intermittency, high predictability
  • Dispatchable, high load factor

Flexible Energy

  • Export opportunities for energy and technology
  • Generation of green Hydrogen
  • Clean energy for remote locations
Phase 1 - TRL 5 - Ground based satellite demonstrator & balloon trials - 2022-26

Phase 1

  • Wireless Power Transmission (WPT) performance parameters established
  • Rectenna design established
  • Solar Power Satellites (SPS) architecture confirmed
  • High Concentration PhotoVoltaics (HCPV) to Radio Frequency (RF) conversion efficiency confirmed
Phase 2 - TRL 6 - 40 MW SPS demonstrator in low earth orbit - 2027-31

Phase 2

  • Meaningful power transmitted from orbit to earth
  • SPS module sizes and configurations established
  • Atmospheric effects to WPT investigated
  • Assembly robots designed
Phase 3 - TRL 7 - 500 MW SPS demonstrator in operational orbit - 2032-35

Phase 3

  • Autonomous in-orbit assembly demonstrated
  • Reflector and structure optimised
  • SPS and WPT control optimised
  • SPS available for commercial power at end of tests
Phase 4 - TRL 8 - 2GW SPS Production prototype in operation orbit - 2036-39

Phase 4

  • Full scale demonstration of the operational system
  • Industrialisation of SPS manufacture complete
  • Space launch capacity and providers in place
  • SPS available for grid connection at end of tests