Is Space-Based Solar Power the Next Big Thing in Space?

The novel method of extracting solar power wirelessly by satellite has not garnered strong attention in recent years, but recent investments and government-backed initiatives have reignited interest in realising the technology.

Enterprising startups, government grants, and massive Chinese projects have driven up interest in space-based solar power (SBSP), which still draws scepticism in the space industry as leaders of industry and markets await favourable results and investor approval.

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Pioneering innovations

In October of last year Space Solar, a British SBSP startup founded in 2022 announced a partnership with Transition Labs to provide Iceland’s Reykjavic Energy with power from orbit courtesy of their new satellite power plant, which is intended to become operational by 2030 with an initial capacity of 30 megawatts.

This satellite is targeting a launch via a SpaceX Starship in 2029, which will then scale with larger systems to produce 15 gigawatts by the mid-2040s.

The realisation of a SBSP tech advantage in the UK will take public and private investment, he says. “The financing system is not well set up to support the development of infrastructure businesses, and timelines start when funding is raised. … but [these solutions will deliver] strong returns and economic benefits to all types of investors.”

Adlen references four funded start-ups developing laser and reflector-based SBSP concepts;

• California-based Aetherflux founded by Baiju Bhatt, the former Chief Executive of Robinhood,
• DC-based Overview Energy backed by venture capital
• California-based Reflect Orbital, which concluded a $6.5 million seed round in 2024
• Montreal-based Volta Space, which emerged from stealth last October, specialising in directing energy to the moon to power Lunar industries

While laser solutions mean smaller products and more straightforward financing, microwave is required for scaling solutions and delivering baseload energy, Adlen explains.

Others startups include California-based Solaren, who experienced difficulty securing the financing necessary to deliver their solution by their 2018 deadline and the Caltech Solar Power Project, headed by the scientists who were the first to demonstrate ultralight satellite power transmission.

Orbital Composites, also based in California, is developing a solution powered by a $1.7 million award from the US Space Force in collaboration with Axiom Space, Northrop Grumman, and Southwest Research Institute.

“For SBSP, the market is there and strong power revenues can be delivered from five years’ time with spillover benefits for governments and spin-out products for investors on the journey to that point,” says Adlan.

Space Solar’s technology is supported by £5 million of engineering research.

Understanding space-based solar power

First proposed in 1968, the notion of generating solar energy under the optimal conditions of space, then transmitted via microwaves to the Earth’s surface seemed outlandish, having been premeditated thirty years prior in science fiction by Isaac Asimov.

Long considered outlandish, but not impossible, the question about the scientific principle had less to do with whether it could be done, and more to do with how its high costs justified the results it could deliver.

With persistent access to the sun and no atmospheric interference, solar panels in orbit have been proposed to be as much as about ten times more efficient than ground-based systems, an advantage augmented by the ability to beam their output directly to areas where it is needed. The difficulty comes with getting it down from orbit wirelessly.

Harry Atwater, a professor at Caltech who helped lead the university’s Space Solar Power Project estimated that in 2023 around 5-12% of energy transmitted from a solar satellite would reach Earth, making it roughly 40% as efficient as Earth-based solar. With an aim to increase the efficiency of the transmission of power from orbit, the maths could dramatically change, resulting in an agile renewable energy solution requiring significantly lower land use than Earthbound solar arrays.

An independent study from 2021 commissioned by the British Department for Energy Security and Net Zero estimated that SBSP could generate “up to ten gigawatts of electricity by 2050”, a quarter of the UK’s current electricity demand, creating 143,000 jobs as part of a multi-billion pound industry. In 2023 the government deployed funding to various universities and R&D groups to deliver technologies to support an edge in UK satellite solar.

A government-backed study into the feasibility of small-scale SBSP is set to conclude in April 2025, which will inform their next steps.

Chinese confidence

In January this year, senior rocket scientist Long Lehao of the Chinese Academy of Engineering delivered a lecture at the Chinese Academy of Sciences describing plans for a massive space-based solar power project akin to “another Three Gorges Dam above the Earth”, referencing the hydroelectric dam on the Yangtze River, the planet’s largest power station by installed capacity.

He went on to describe a one-kilometre solar array 36,000 kilometres above the earth that would surpass the power output of the Three Gorges Dam, which delivered around 100 billion kWh annually. The efforts are part of the ZhuRi programme, meaning ‘chasing the sun’, which aims to have operational space solar by 2035.

The professor described the “Three Gorges in space” analogy as an assumption, insisting “There is long way to go to make it real.”

Sam Adlen insisted these claims shouldn’t be dismissed as hyperbole. “It is important to take Chinese ambitions very seriously as when they set their mind to something they are incredibly capable and execute extremely well,” he said.

Early and heavy Chinese investment in next-generation lithium-ion batteries for use in electric vehicles sent serious economic shocks through Europe and America in 2024, setting Western economies off course of their plans for transitions to net-zero industry, which resulted in sanctions intended to protect the development of domestic industries.

“Pursuing space-based solar power is a no-regrets move,” Adlan insists. “You create [jobs and empower supporting technologies] on the journey with wireless power transmission and in-space assembly of large structures, but if others [such as China] succeed, the path of no action is a potential big-regrets approach.”

Many experts worry China’s sciences and technology ambitions and proactive economic policy mean the country will secure first-mover advantage on a number of deep technologies which could come to define the 21st century such as quantum computing, generation IV nuclear reactors, and more recently AI. While technological supremacy in space is more hotly contested, China has made great strides in the field through the Cina Aerospace Science and Technology Corporation (CASC), which outpaces SpaceX in terms of total launches and satellites orbited.

An obstacle of public opinion?

Given the hysteria around advancements like 5G, nuclear power, and chemtrails, it’s only natural to anticipate public trepidation around moving gigawatts of energy via microwave through Earth’s atmosphere, capable of bordering on conspiracy.

Studies by NASA and The Royal Society have produced positive results in terms of safety, but others, such as the Frazor-Nash Consultancy in a 2022 report on SBSP, maintain safety will be subject to “regulation on safe microwave power limits” and safeguards against losses of beam lock to the rectenna. If the rate of power transmission is scaled to compete with the output of power stations, the safety of such beams could be impacted.

With such extended timelines, spreading onto the 2040s and 50s, much of the history of satellite solar transmission leaves decades for nations and authorities to change course. In a few decades, dynamic baseload power allocation via satellite could have become a cornerstone of net-zero energy assurance, or SBSP could go the way of Concorde and prove environmentally unsuitable. Whatever the case, this fascinating technology will be one to watch.

Sources: www.orbitaltoday.com