What does space-based solar power mean for the future of fossil fuel-based energy? How will it help us achieve our net zero targets?
Since John F Kennedy challenged the USA with his ‘moonshot’ in 1961, and put a man on the moon within a decade, we have been transfixed with not just the spectacle of space travel and exploration, but also by the opportunities for research, development and technological advancement that space provides.
One of the major technological advances of the last three decades had been the development of the International Space Station, which has now been on-orbit for over 20 years, and which has provided a platform for a continuous occupation of space. It is a shining example of the potential for large orbiting structures to successfully operate over long periods.
The presence of the Space Station on-orbit has generated a market for on-orbit services, which includes regular supply missions, the launch of satellites and human spaceflight. Fuelled by the demand for these services and the subsequent reduction in the price of launch, commercial and non-commercial providers have been able to develop capabilities for the deployment of large satellite constellations. The growth of the commercial sector has culminated in Space-X securing the contract to run crewed missions to the moon for the US Government.
By combining the advances in launch capabilities, our ability to construct and operate massive structures on-orbit and the ready availability of solar energy in geostationary orbits, we are now, more than at any time in history, in a position to conceive and deliver a space-based solar power system, capable of providing clean base-load energy for planet earth. The idea is an old one, but it’s the recent advances in launch and on-orbit operations that now finally make it viable.
Energy from the Sun
Let’s first consider the vast energy resources from the Sun that can be harnessed from space. There is 100x more solar energy available from a narrow strip around the earth in a geostationary orbit, than the forecast global energy demands of humanity in 2050. The earth also receives more energy from the sun in a year that will ever be produced from all fossil fuels or nuclear power on earth. Those are powerful statistics.
With the UK committed to fully decarbonise the economy by 2050, a major consideration is the delivery of energy through clean and sustainable energy generation from renewable sources. But the energy we generate must remain affordable, reliable and secure for our economy to continue to prosper. This is where solar energy from space stands out from the alternatives.
Space-Based Solar Power
The concept of space based solar power encompasses all type of orbiting systems that harvest sunlight and transmit that energy to the Earth. It’s not a new idea, with the concept going back to 1968 and an American scientist named Dr. Peter Glaser. 
But it is an idea with significant potential, particularly when it comes to delivering clean, base-load energy with fewer of the problems associated with wind and solar energy.
There are several viable concepts for delivering space-based solar power but a typical example is based on a constellation of satellites situated in geostationary orbit. The satellites are vast, with arrays extending to kilometers in diameter. Each one would feature a set of lightweight solar panels and a system of mirrors which are used to concentrate sunlight onto the panels. The sunlight energy would then be converted into microwave radiation, at a frequency which would allow the energy to pass through our atmosphere and clouds without being affected – meaning that the supply of energy would be consistent, no matter what the conditions on Earth.
The beam of energy would then be transmitted to a fixed point on the ground, where it would be converted into electricity, ultimately delivering around 2GW of power into the national grid. By comparison, the average output of a nuclear reactor in the UK is around 3GW. It is also cost-effective. A first of a kind 2GW space based solar power system would cost approximately £16Bn NPV compared with an estimated £22-£23Bn for Hinckley Point C. Future systems would be even cheaper to develop with an estimate of only around £3Bn per array.
Because the satellite in orbit can always see the sun, the amount of power generated is consistent day and night, as well as in all weathers. The power can also be beamed to different locations without the need for connecting infrastructure which will enable the grid to be considered in different ways in future.
It sounds like science fiction, but it is already subject to a study that shows it is technically viable and economically favourable compared with other clean baseload technologies. Furthermore, it’s already being explored by other sovereign nations, with China and the USA in particular committed to funding the delivery of working concepts, with the American project set to deliver a working small-scale concept by 2023.
The Road to Net-Zero
The goal of net zero is certainly challenging for the energy sector. Solar and wind power are now significant contributors to energy needs in the UK and the growth of the industries surrounding them has meant that costs have fallen and efficiency has improved. But there are still challenges to overcome with their intermittent nature and the amount of land they require to be effective. Nuclear solutions form a part of the UK government’s 10-step plan to net zero, but their futures are uncertain, not least because of their perception amongst the public. It’s clear that hydrogen is also an important part of decarbonisation, but clean, affordable and sustainable energy is needed to produce it.
The challenge of delivering continuous base-load power, as part of a balanced energy mix remains.
So, for the UK, it’s all about the size of the prize. Space based solar power could provide consistent, reliable and clean base-load power for the UK economy in 2050. Base-load is the important point, because providing base-load power is something that other renewable sources are not good at, and therefore it provides an alternative to the long-term use of fossil fuels, particularly natural gas. But it needs investment and commitment from current and future governments if it is going to become a reality. However, there is strong potential for building international partnership, and leveraging private investment if the government can make a clear commitment. The spillover technological, and innovation benefits are also vast, including power beaming technology and robotic assembly in space.
The concept is certainly a moonshot for the 21st century, but with the potential it offers for the delivery of clean base-load energy, it is a lot less risky than the thought of putting a man on the moon was back in the 1960s. It will also cost significantly less, and will enable us to deliver the imperative of Net Zero whilst simultaneously driving massive technological benefits and economic growth.
The question is, why haven’t we done it already?
 Caltech announces breakthrough $100 million gift to FUND space-based solar Power Project. California Institute of Technology. 2021, August 3). https://www.caltech.edu/about/news/caltech-announces-breakthrough-100-million-gift-to-fund-space-based-solar-power-project.