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Space-Based Solar Power Opens a New Track for Clean Energy

Source: Science and Technology DailyAuthor: Liu Xia
As the electrification of human life continues to advance and big data and artificial intelligence technologies develop rapidly, global energy demand is growing at an unprecedented rate. While terrestrial renewable energy sources such as wind and solar power are important, they are intermittent and require vast amounts of land. Against this backdrop, space-based solar power (SBSP) may emerge as a new path toward a truly clean and abundant energy future.
According to a recent report on the World Economic Forum's official website, with the decline in launch costs and advances in large-scale manufacturing technologies, space-based solar power has become technically and economically feasible, promising to be a rich and sustainable new energy source. Of course, to turn this vision into reality, several key technical obstacles must still be overcome, such as further reducing launch costs and improving the efficiency of power transmission to Earth.
Multiple Advantages and Broad Prospects
Wind and solar power generation are significantly affected by weather and environmental factors. For example, terrestrial solar power is vulnerable to cloud cover, leading to unstable supply, while traditional nuclear power plants produce radioactive waste, posing pollution risks. In contrast, sunlight in space is 5 to 10 times stronger than on the ground, providing not only abundant energy but also continuous and clean electricity.
Space-based solar power is a power generation system deployed in Earth's orbit. It collects energy through solar panels and transmits it wirelessly to receiving antennas on the ground. This concept was first proposed by American scientist Peter Glaser in 1968: large solar satellites would be deployed in geostationary orbit approximately 36,000 kilometers from Earth, allowing them to be bathed in sunlight around the clock. These continuous solar energy would then be converted into microwaves and transmitted to ground receiving stations. The microwaves themselves are safe, with a peak intensity of about 230W/m²—equivalent to one-fourth the intensity of noontime sunlight.
As early as the 1970s, space-based solar power was considered technically feasible. However, it is only in the past decade, with the decline in launch costs and breakthroughs in large-scale manufacturing technologies, that it has truly become economically viable.
The advantages of space-based solar power are significant: it can provide stable and reliable baseload power—a continuity previously only achievable with fossil fuels or nuclear energy. Additionally, the higher light intensity in space enables space-based solar panels to generate far more electricity per unit area than their terrestrial counterparts, thereby saving substantial land resources. A recent study by NASA even predicts that a space-based solar power model could generate electricity 99% of the year.
This high energy density is also expected to significantly reduce material consumption, making it more sustainable and helping to alleviate resource pressures. Meanwhile, space-based solar power offers highly flexible dispatch capabilities. Each satellite can cover a quarter of the Earth's surface, enabling nearly instantaneous intercontinental power transmission, much like an efficient "energy interconnection hub" in space. Studies suggest that space-based solar power could meet most of humanity's energy needs at a highly competitive cost.
Multiple Countries Competing for Layout
A "space race" centered on sustainable energy has begun, with countries and private enterprises around the world increasing their investment in space-based solar power.
In August 2023, the space-based solar power demonstration prototype developed by the California Institute of Technology achieved the first wireless energy transmission in space. The prototype, equipped with a lightweight microwave transmitter called MAPLE, completed solar energy collection and transmission in space, not only lighting a pair of LED lights but also sending energy back to Earth—where the receiver on the roof of the Gordon and Betty Moore Engineering Laboratory at Caltech accurately captured this "gift from the sky."
China is also steadily advancing its goal of building a kilometer-scale array, with plans to achieve a breakthrough by 2028. Currently, two major platforms—the "Space-Based Solar Power Station Experimental Base" in Chongqing and the "Full-Link Ground Demonstration and Verification System" in Xi'an—have started construction. Among them, the Xi'an system completed a full-link energy conversion and transmission experiment in June 2022, achieving microwave energy transmission over a vertical distance of 55 meters with a transmission power exceeding 2 kilowatts. According to the technical roadmap released by the Chinese Academy of Sciences, China is expected to complete the first commercial space solar power generation system between 2030 and 2050.
The European Space Agency launched the SOLARIS pre-research program in January 2023, planning to invest 60 million euros over three years to tackle core technologies such as solar cells, energy converters, and space robots, paving the way for on-orbit verification after 2025.
The United Kingdom has also joined the ranks of space-based solar power "players." According to a report on a British technology news website on April 28 this year, the UK's "Constant Aperture, Solid-State Integrated, Orbital Phased Array" (CASSIOPeiA) concept has been adopted by the government as the starting point for a space-based solar power plant demonstration project. Several companies involved in the project plan to deliver a commercial system within six years. The UK has also established the Space Energy Initiative, consisting of over 90 industrial, academic, and government organizations, to accelerate the development of space-based solar power.
Japan has listed space-based solar power as a key development direction and continues to conduct critical technology verification. In December 2024, the Japan Aerospace Exploration Agency (JAXA) and aerospace system companies successfully completed a long-distance air-to-ground microwave energy transmission experiment: an aircraft equipped with a transmitter accurately transmitted microwaves to the ground from an altitude of 7,000 meters, and 13 receiving devices deployed on the ground successfully captured the energy.
Numerous Technologies Await Breakthroughs
Despite its broad prospects, realizing the grand blueprint of space-based solar power requires breakthroughs in several key technical fields.
First is the challenge of launch costs. Although global satellite launch costs continue to decline, the European Space Agency notes that building the International Space Station required dozens of launches, and the number of launches needed for larger space-based solar power stations will be even more staggering. Fortunately, the maturity of reusable rocket technology is significantly improving space economics, injecting strong momentum into the commercialization of space-based solar power.
Second, technical challenges are equally formidable. While wireless energy transmission over several kilometers has been achieved, efficiently and stably transmitting gigawatt-level power back to the ground remains a major technical bottleneck. At the same time, how to use autonomous robots in space to accurately assemble and maintain Giant space structures has also become a critical technical hurdle to be overcome.


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