EDITORIAL 1: Could we soon have space-based solar panels? Not really
Context
Solar power is the fastest-growing renewable energy technology in the world. Between 2024 and 2030, solar capacity added is expected to account for 80% of the growth in renewable power globally, the International Energy Agency’s ‘Renewables 2024’ report stated.
Several limitations
- But this power source has several limitations. It can only operate in the day, is sensitive to the vagaries of weather, and requires a lot more space per unit of electricity produced than most other technologies.
- A silver bullet to solve these problems: space-based solar power (SBSP). This is not a novel idea.
- But recent technological advances have given it new wings. A latest study by researchers from King’s College, London has estimated that SBSP could supply up to 80% of Europe’s renewable energy needs by 2050.
Promise of SBSP
- The study, published in the journal Joule last week, says satellites in geostationary orbit could harvest continuous sunlight and beam it to Earth as microwaves, delivering dispatchable, zero-carbon power that sidesteps the intermittency plaguing wind and solar on the ground.
- To make its assessment, researchers carried out multiple simulations of two concepts developed by NASA.
- One, a nearly continuous heliostat swarm design and an intermittent planar array design, yielded positive results.
- This design uses mirror-like reflectors to collect sunlight in orbit, transmit this energy to stations on Earth, which then convert it to electricity.
- Such a design effectively addresses all major problems with solar power on Earth.
- In space, you potentially have the ability to position solar panels to always face the sun, which means power generation can be nearly continuous compared to the daily pattern on Earth.
- And, because it’s in space, the solar radiation is higher than on the Earth’s surface.
Reasons for scepticism
- While SPSB is based on existing technological principles and known physics, making it economically viable remains a challenge — one which the study does not tackle.
- The main issue is that such a system would require setting up very large structures on Earth and in space.
- A single solar power satellite at geostationary orbit might extend more than a kilometre across, with the receiver station on the ground needing a footprint more than ten times larger.
- A enormous number of launches — possibly running into the hundreds — would be required to set up a single solar satellite which could produce the equivalent of a conventional nuclear power station, according to ESA’s website.
- For context, the much smaller International Space Station was built with more than 40 assembly flights.
Some challenges
- Despite progressively declining launch costs, the sheer scale of space infrastructure required is an impediment to SPSB being viable.
- According to a report in The Guardian, it is unlikely that the potential cost-effectiveness of SBSP could be realised until 2050 because building, launching and maintaining it would be too expensive unless technological growth reduces its costs.
- The researcher’s modelling also does not take into account space-specific challenges such as orbital congestion, transmission interruptions or beaming variability, which could influence SBSP reliability and operational performance.
Conclusion
Apart from some challenges, the SBSP seems promising to bring a change in the solar sector.