Why the solar power stations of the future could be based in space

A breakthrough in how to reliably send electricity back to Earth could prove revolutionary for renewable energy growth

UK-based start-up Space Solar is hoping to have a pioneering system up and running, delivering a set-up capable of beaming back 30 megawatts of energy to Earth by 2030. Photo: Space Solar

An environmentally friendly solution to keeping the lights on – even when there's not enough sunshine for your rooftop solar panels nor wind for turbines at sea – may lie not here on Earth but far above the clouds.

Solar power generated in space can be sent to Earth from a large satellite, about a kilometre wide, which captures the sun's rays with mirrors before concentrating them onto panels to produce electricity.

Scientists say they have solved one of the biggest engineering problems that for long faced space-based solar power: how to safely and reliably send this electricity to the ground, using high-frequency radio waves.

UK-based start-up Space Solar is hoping to have a pioneering system up and running, with an investment of $800 million, delivering a set-up capable of beaming back 30 megawatts of energy to Earth by 2030.

The system can wirelessly transmit power to ground stations round the clock, which is then continuously fed into the grid. The company's plans for beaming energy to earth stations in Iceland are already on the drawing table.

With the UAE, Saudi Arabia and other countries in the Middle East committed to becoming major players in generating the green energy needed to curb climate change, the technology breakthrough is drawing interest across the region.

Martin Soltau, Space Solar's joint chief executive, told The National the technology promises an “economic revolution” as the world strives to move towards its goals of net zero emissions, in an accelerated time frame that has raised questions about reliable sources of power to keep the lights on.

"We're trying to do it very quickly but wind and solar are intermittent and the storage that you need to give you reliable, affordable energy doesn't really exist yet," he said.

“So what’s happening is that you end up with two energy systems. You’ve got your intermittent renewables and then a second energy system, which is the back-up. What space-based solar power can do is transformative because it provides this continuous supply. Day and night, all weather energy.”

The science behind space-based solar power has been known for decades, but costs slowed research and development work.

Now, with Elon Musk's SpaceX company and others inventing reusable rockets and lowering the cost of transporting goods to space, the day when such a solar power plant can be assembled in space is coming ever closer.

Space Solar has already been undertaking “bit of deep technical work” with Saudi Arabia’s Neom project on providing energy, said Mr Soltau. There have also been in discussions with government and the private sector in the UAE.

The start-up has been exploring opportunities elsewhere in the Middle East. A representative recently told a conference organised by the Arab British Chamber of Commerce that Libya may also be a good location as a base station in future.

Mr Soltau believes the technology is ideally suited to help countries in the Middle East make the transition from hydrocarbons to green energy without having to invest heavily in nuclear power.

The region has many mountains but not enough water to make hydroelectric power feasible and nuclear takes a “long, long time to build”. There is even potential to for exporting energy.

Space-based

“Of course a lot of the Middle East countries rely on fossil fuel exports. Well, this gives another form of export in an incredibly flexible way. So it really could be a great transition for those economies," he said.

“The Middle East is brilliant in many ways and the UAE is a leader in kind of ambitious technology in many ways. If you think of a partnership with, let's say, the UK and the UAE.

"You can be running the UAE on terrestrial solar in the day, and exporting the space-based solar power to Northern Europe or the UK, because we've got drizzly cloud. Then at night, the space solar power is powering the UAE.”

Such an energy partnership would see a UAE-based "operator switching the beam to supply to a UK-based rectenna [a special type of receiving antenna for converting electromagnetic energy] directly from the satellite", Mr Soltau added.

"One of the many advantages of space-based solar power is that it can beam near to the point of demand, and thus minimise the requirement for expensive and vulnerable grid transmission cables," he said.

If the idea sounds like science fiction, then that’s probably because it emanated from that realm. In 1941 science fiction author Isaac Asimov set his short story Reason on a solar power satellite that is beaming energy in the form of waves not only down to Earth, but also to other inhabited areas of the solar system.

At first glance, the sheer size of the satellite Space Solar plans to put into orbit raises questions about how it can be transported.

Dish construction

The solution, said Mr Soltau, lies in the thousands of identical parts that comprise the satellite, being taken up in stages and then assembled in space itself.

“The size and scale of these things is that they're made of hundreds of thousands of identical Lego bricks. The power modules are all identical,” he added.

"They're made in gigafactories, just like our laptops and then transported up to space. Think of Amazon warehouse robotic assembly machines.

The challenge is to “get good at the space assembly of these large structures, which we haven't really done before at this scale'" said Mr Soltau.

"We completely understand the physics and the dynamics of how to do this, but it hasn't been done.

"And so that's a big engineering development in its own right, but it can be done.”

Space Solar’s first foray into supplying energy will come in the form of a deal with Iceland’s Reykjavik Energy, which will be a customer for the 30MW plant. Iceland has other sources of clean energy including geothermal power, but demand is growing as more data centres open in the country.

Space Solar is not alone in the field and other companies are pursuing the technology in Japan, China, America and elsewhere. A US-based start-up, Aetherflux announced in October that it aims to set up a constellation of smaller and cheaper satellites in low Earth orbit, rather than a large single unit favoured by Space Solar.

The cost of producing the energy is the biggest hurdle Space Solar and other companies are looking to surmount.

Lowering costs

US space agency Nasa found that space-based solar could be 12 to 80 times more expensive than terrestrial alternatives. But its authors admitted they had to make assumptions because the technology is so new and cost is really dominated by launch and manufacturing.

Mr Soltau points to the ability of Starship, SpaceX’s reusable heavy rocket, which has become the tallest, heaviest and most powerful vehicle to fly, to help win the battle.

“Space solar power has really long been considered the ultimate form of clean energy, but it's always been too expensive until Elon Musk came along and showed and operationalised reusable rockets," he said.

“Starship is now fully reusable with huge capacity, 100-plus tons per launch. And these are the two things we need. We need high capacity to launch these things rapidly, and we need very low cost.

“If launch costs, as many analysts think, are coming down below $500 possibly to $100 per kilogram, then space based solar power will become incredibly cheap and far cheaper than wind and solar.”

Space Solar has received £10 million from the UK government but is now hoping to attract private investors, including infrastructure funds and energy companies.

“Space-based solar power has been in the wings for a long time, and a sort of small group of people have been aware of it, that of its sort of huge potential," the chief executive added.

“But others need to be convinced and I think as soon as somebody puts up a substantial proof of concept into space, then there will be a big rush to develop these systems.”