Harnessing the sun: The next frontier in the quest for sustainability

According to IPCC data, the energy sector accounts for 34 per cent of human-caused greenhouse gas (GHG) emissions, remaining heavily reliant on fossil fuels despite a surge in renewable energy sources.

Despite unprecedented growth in recent years, solar and wind cannot fully meet our energy needs or achieve net zero, much less a regenerative economy. Storage, land use, and availability remain significant challenges in harnessing the full power of renewables.

Global energy demand will continue to grow, even outpacing advances in energy efficiency (Sanicola and Kelly, 2023), adding hurdles to the objective of decarbonizing our economies. Innovation has been the catalyst for change in human history, and even in the energy field, a new frontier technology promises to give us unlimited energy: Space-Based Solar Power (SBSP). It still sounds like a science fiction idea to many, but it is now gradually becoming a viable reality and is expected to be within our reach in the next decade. This is not a new concept (Mankins, 1997); however, the recent evolution of the space industry has dramatically decreased costs and enhanced the viability of SBSP projects.

How does it work? Here is a simplified summary of the process, broken down into four steps:

• Energy collection: Large satellites equipped with expansive solar arrays capture consistent solar radiation in high Earth orbit.

• Energy conversion and transmission: The captured solar energy is then converted into microwaves, which can traverse the vast distances between the satellite and the Earth without significant loss.

• Power reception: On Earth, giant ground stations receive microwave signals and convert them back into electricity.

• Grid integration: This electricity is then fed into the national grid, just like power from conventional sources.

^{Image source: Space Solar}

Several consortia are currently developing the concept, with Space Solar in the UK among the most advanced (Hollinger, 2023). We spoke with Martin Soltau, the CEO and a leading expert in SBSP.

The biggest advantage, as Martin argues, is that solar panels in space can collect about 40% more energy than those on Earth. Positioned in high Earth orbit, these panels can harness the sun's energy 24/7, converting it into microwaves that are beamed down to Earth. These microwaves are then captured by ground-based receivers called rectennas and converted back into electricity for distribution through the grid. "Space-based solar power is set to be a game-changing clean energy technology, decades before nuclear fusion becomes viable," Martin says.

This technology addresses two major limitations of terrestrial solar power: intermittency and efficiency. On Earth, solar power is subject to fluctuations due to weather conditions and the natural day-night cycle. In contrast, space-based solar power can provide a continuous, stable energy supply, making it a crucial component in achieving global energy security and reliability. "The really important thing is that you're getting continuous energy 100% of the time, which is crucial for our global energy systems," Martin asserts, highlighting this as a potential game-changer for our energy needs.

Another important factor is scalability. Martin explains, "Unlike traditional energy infrastructure projects that take decades to build, space-based solar power can be quickly expanded to meet growing energy demands. We can build tens of gigawatts per year, not just two gigawatts over ten years." This solves an important problem of many energy projects that have huge delays, like nuclear power plants, for example (Lawson, 2024).

However, how viable is SBSP? Its viability is increasing thanks to reusable rockets and increased payload capacities, which have dramatically reduced space deployment costs. Well-known companies like SpaceX and Blue Origin are leading this change.

Therefore, this is not a technology for the distant future. Martin boldly points out that by 2030, Space Solar plans to beam 1 MW of power to Earth, with ambitions to scale up to several GWs. It is a very ambitious plan backed by the UK Government. They have successfully demonstrated the world's first 360° Wireless Power Transmission (see Space Solar's breakthrough here). "Space Solar’s successful testing of HARRIER marks a pivotal moment in our mission to revolutionize solar-based power. With this demonstration of the world’s first 360° wireless power transmission, we’re not only advancing our own capabilities but also laying the foundation for a brighter, cleaner future for generations to come," commented Martin.

However, challenges remain. A key factor, Martin notes, is the regulatory aspect and the need for international cooperation. Spectrum allocation is usually a tedious and lengthy process. Public acceptance, as with any new technology, is critical.

Another factor is the substantial size of the receivers. Additionally, some technical issues, like beaming and space construction, despite the advances, are still in the early stages. The ground receivers, or rectennas, required to capture the beamed energy and convert it back to electricity are large structures, typically about three and a half kilometers in diameter for a one-gigawatt system. Finding suitable locations for these rectennas, especially in densely populated or environmentally sensitive areas, can be challenging.

Martin stresses the importance of cooperation and support between the government, private sector, and the public to enable smooth and rapid deployment of the technology and to help reduce the capital expenditures involved. "Governments need to come in a big way in the early days. It’s a classic case of this nascent market where there’s a strong market for clean energy, but it needs strong government funding support," he argues.

SBSP holds promise in our quest to decarbonize our economies. Companies like Space Solar are at the forefront of this revolution, aiming to provide continuous, affordable, and reliable energy. Regulatory hurdles, public acceptance, and technical barriers remain challenges to be solved. However, the next few years could be decisive for the practical deployment of this promising technology. 

illuminem Voices is a democratic space presenting the thoughts and opinions of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.

References

To learn more, https://www.spacesolar.co.uk

Hollinger, P. (2023) How to make space-based solar power a reality [online] https://www.ft.com/content/2d43ed21-9f9d-4e90-a18b-ad46f0a4760d

Lawson, A. (2024). Hinkley Point C could be delayed to 2031 and cost up to £35bn, says ED   [online] https://www.theguardian.com/business/2024/jan/23/hinkley-point-c-could-be-delayed-to-2031-and-cost-up-to-35bn-says-edf#:~:text=Of%20that%20delay%2C%2015%20months,risks%20are%20now%20behind%20us”.

Mankins, J. C. (1997). A fresh look at space solar power: New architectures, concepts and technologies. Acta Astronautica, 41(4-10), 347-359.

Sanicola, L., & Kelly, S. (2023). Global energy consumption to increase through 2050, outpace efficiency gains, EIA says [online] https://www.reuters.com/business/energy/global-energy-consumption-increase-through-2050-outpace-efficiency-gains-eia-2023-10-11/