Scottish research develops solar power system for after sundown

A Scottish university has unlocked the power of solar panels beyond sundown using reflectors from space.

The University of Glasgow has developed a system able to power solar farms for an extra two hours per day on average.

With solar power playing an “important role” in the Scottish Government’s draft energy strategy and just transition plan, the breakthrough may accelerate the transition to net zero, researchers have said.

Dr Onur Çelik, author of a new study on the matter, said: “One of the major limitations of solar power, of course, is that it can only be generated during daylight hours. Putting orbiting solar reflectors in place around the Earth would help to maximise the effectiveness of solar farms in the years to come. 

"Strategically placing new solar farms in locations which receive the most additional sunlight from the reflectors could make them even more effective.” 

Space engineers have developed an algorithm able to arrange reflectors in orbit so that they catch sun rays more effectively, maximising the additional sunlight bounced to solar farms. 

In Scotland, it is thought that this could be especially advantageous during the winter months, when average daylight can be as low as six to seven hours. 

Having access to solar energy post-sundown would also help meet demands for electricity, which tend to be higher from 8pm to 10pm.

By generating an extensive power boost (728 MWh) for already-built solar power stations, the algorithm could also make the journey to net zero more cost-effective and efficient, it is claimed.

The research also showed that by placing 20 reflectors 1000 kilometres from the surface of the Earth, these would remain close to the Earth’s terminator line – the boundary where daylight on one side of the planet transitions into night on the other, also known as the Walker constellation.

The study is one of the outputs from SOLSPACE, a University of Glasgow-led research project supported by a £2.1m fund from the European Research Council. 

Colin McInnes, SOLSPACE principal investigator, said: “Tackling the challenges of climate change requires big ideas. While this is undoubtedly a big idea, it builds on technologies that are already well-understood and computer models like ours show how they could be scaled up. In addition, the falling cost of launching payloads to space opens up entirely new possibilities for the future.” 

Space reflectors date back to the late 1920s. However, they have only been demonstrated once in the 90s, when a “20-metre aluminium-foil reflector was released from the Russian Mir space station to reflect sunlight back to Earth”, McInnes added.

The paper, titled A constellation design for orbiting solar reflectors to enhance terrestrial solar energy, has been published in the scientific journal Acta Astronautica.

Has Scotland been embracing solar power?

Since 2020 there has been a 174 per cent boost in the number of installations of solar panels across Scotland, with 2023 figures standing at 26,000, according to the MCS Foundation database.

However, in June the Scottish Government scrapped its solar panel loans in what Solar Energy Scotland’s senior policy advisor Emily Rice described as “an entirely unexpected and inexplicable move”.

The government announced the loan would now only be available “as part of a 

package together with a heat pump or high heat retention storage heaters”.

Following the announcement, Lib Dem MSP Willie Rennie said the decision was “mind-bogglingly counterproductive” and urged the government to reverse it to meet net-zero targets. 

The Scottish Government is committed to deploying between 4-6GW of solar power by 2030.