Space-based solar: baseload power from the sun 24/7

Satellite with solar panels in Earth's orbit (space-based solar)

Space-based solar is fast gaining traction around the world as a viable future renewable energy source to provide baseload power, writes Frazer-Nash Consultancy space business manager Martin Soltau.

It requires a constellation of large satellites in Geostationary Earth Orbit (GEO), where they are illuminated by the sun more than 99 per cent of the time. A solar panel in space collects up to 13 times more energy than the same solar panel on earth. 

Autonomous robots would assemble the satellite modules in Medium Earth Orbit (MEO) to avoid the risk from space debris in Low Earth Orbit (LEO), and above the harsh radiation environment of the inner Van Allen belt. The assembled satellite would be raised up to GEO using very efficient solar electric propulsion.

Related article: Building a solar farm in space? Yes, we can

The satellites then collect solar power, convert it into high frequency radio waves and beam it to rectennas on the earth. A proposed radio frequency in the 1–10GHz atmospheric window makes it capable of beaming at full power irrespective of the seasons and weather. The rectennas convert the radio waves into electricity and each satellite delivers around 2GW of power into the grid.

Space solar could provide an almost endless stream of clean baseload power by 2050 and should be seriously considered by Australia as part of its future energy mix. There is already a lot of work happening around the world to advance this technology, and Australia can become an important player going forward. 

Decarbonising and achieving net-zero goals sustainably will be very difficult with existing technologies, especially for countries without nuclear power. Battery storage costs need to come down by at least two orders of magnitude to be viable. Meanwhile, coal-fired power stations are closing down faster than governments and the regulator expected, and this could impact household bills.

Space-based solar power is clean, capable and competitive. It is scalable and it offers a truly sustainable, clean energy future. It would also reduce the cost of energy for households and industry by providing baseload and despatchable power, while giving Australia energy security and sovereignty.

We are still uncovering other benefits of space-based solar power. New research from the Space Energy Initiative (SEI) has shown that space solar is also environmentally friendly. The University of Strathclyde, which is a member of the SEI, recently completed a Life Cycle Analysis of a Cassiopeia space-based solar power system, and calculated the carbon footprint as 24 gCO2/kWh. That’s about half that of terrestrial solar.

  This is because SBSP systems have a very high energy flux. Each satellite would be able to beam two gigawatts into the grid constantly, similar to a conventional power station, providing power for one million homes. The satellite uses high concentration photovoltaics with around 6,000 times less area than traditional solar panels. This is game changing from the perspective of rare earth mineral resource usage and economics.

Even the economics of a space solar program are looking more and more favourable. The cost of space launch—one of the dominant costs—has fallen by 90 per cent in the last decade, and that is set to drop even further with the use of reusable rockets. 

The cost of space hardware has fallen by 99 per cent for mass produced, modular systems like Starlink satellites. Technology in robotics and PV is continually advancing. 

A collaboration between Australia and the UK would be beneficial in terms of developing international regulations and standards, building our space capabilities, and developing technology. New industries and spin-off applications will be spawned. The SEI is reaching out for international partnerships, and Australian company, Solar Space Technologies, is also seeking funding.

Other nations—notably China, Japan and the USA—are taking space-based solar seriously, and there is also growing interest in Canada, South Korea and the European Space Agency. In the UK, Frazer-Nash Consultancy recently delivered a feasibility report for the UK Government, which concluded that space solar power is both technically and economically viable, and could deliver substantial economic benefits and support pathways to net zero.

Related article: Flexible solar cell tech goes to space

The Space Energy Initiative (SEI) is a collaboration of more than 50 leading space and energy organisations and was established following the publication of the Frazer-Nash report, to take forward the development of space-based solar power. It is working closely with the UK Government, which has signalled strong support for space solar in its clean energy technology program and the National Space Strategy. The SEI has a 12-year plan and is developing an ambitious partnership between public and private financing to raise £16 billion. Given the necessary funding and international partnerships, this project will lead to an operational solar power station in 2035. 

The appetite for technologies such as space-based solar power is only going to increase, and this could be a key part of Australia’s future energy mix. Visit