China’s plan to build a 1-kilometer-wide space-based solar power station

Posted on March 16, 2025, by Soraima

China’s plan to build a 1-kilometer-wide space-based solar power station is indeed a real and ambitious project that has been in development for several years, backed by serious scientific and engineering efforts. However, while the concept is legitimate and grounded in ongoing research, it remains in the early stages, with significant technical and logistical challenges ahead. Its full realization is still uncertain and likely decades away. Let’s break it down based on available information.

The idea stems from the concept of Space-Based Solar Power (SBSP), which involves collecting solar energy in space—where sunlight is more intense and uninterrupted by weather or night cycles—and beaming it back to Earth as microwaves or lasers. China has been actively pursuing this since at least 2019, when reports emerged of a testing facility in Chongqing’s Bishan district aimed at verifying microwave transmission technologies. This facility, funded with an initial 100 million yuan (about $15 million), uses tethered balloons to simulate power collection and transmission, showing early practical steps.

Key milestones support its legitimacy. In June 2021, China began constructing an experimental space solar power station in Bishan. By November 2023, researchers from Xidian University completed the world’s first full-chain ground verification system, dubbed the “Chasing Sun Project,” demonstrating microwave power transmission and beam efficiency. This was a significant technical achievement, hailed as world-leading by some experts. Plans escalated in 2022 when China advanced its timeline, targeting a 2028 launch of a trial satellite at 400 kilometers altitude to test energy transmission, followed by a larger station in geostationary orbit (36,000 kilometers) by 2030, capable of 10 megawatts output. The long-term goal is a gigawatt-level commercial station by 2050, with a 1-kilometer-wide array.

Leading the charge is Long Lehao, a respected rocket scientist from the Chinese Academy of Engineering, who has likened the project to “another Three Gorges Dam in space.” His team is developing the Long March-9 (CZ-9), a reusable heavy-lift rocket with a 150-ton capacity, essential for lofting the station’s components into orbit. The comparison to the Three Gorges Dam—producing 100 billion kWh annually—underscores the scale: the space station could theoretically harvest energy equivalent to Earth’s total extractable oil in a year, given space’s 10-times-higher solar intensity.

So, is it legit?

Yes, in the sense that China is genuinely investing in the technology, with tangible progress like ground tests and a clear roadmap. State-backed institutions like the China Academy of Space Technology (CAST) and the Chinese Society of Astronautics are involved, lending credibility.

However, skepticism is warranted. Building a kilometer-wide structure in space, assembling it with dozens of launches, and ensuring safe, efficient microwave transmission over 36,000 kilometers pose massive hurdles.

Critics argue the costs could outweigh benefits compared to terrestrial renewables, and no nation has yet deployed a fully operational SBSP system. China’s not alone—Japan, the U.S., and the UK are exploring similar concepts—but all are still in proof-of-concept phases.

The narrative of “endless power” or outpacing all Earth’s oil is aspirational, not guaranteed. Current estimates suggest a 2-gigawatt station by 2050, but that’s speculative, hinging on breakthroughs in materials, robotics, and energy transfer efficiency.

For now, it’s a legitimate project with real momentum, but its ultimate success remains a long-term gamble, not a done deal.

Sources

• South China Morning Post (SCMP) - A January 9, 2025, article titled "China plans to build ‘Three Gorges dam in space’ to harness solar power" provided foundational details. It quoted Long Lehao, a prominent rocket scientist, describing the project as akin to moving the Three Gorges Dam into a geostationary orbit at 36,000 kilometers.

  
  

• Interesting Engineering - A January 10, 2025, piece, "China plans half-mile-long solar power station for unlimited power," corroborated the SCMP’s timeline and added specifics about the Long March-9 (CZ-9) rocket’s role, with a 150-ton lift capacity, and the Bishan experimental facility started in June 2021. It also noted the "Chasing Sun Project" results from November 2023 by Xidian University.

  
  

• Live Science - Published January 14, 2025, "China plans to build enormous solar array in space — and it could collect more energy in a year than 'all the oil on Earth'" expanded on the technical vision, emphasizing microwave transmission and the geostationary orbit plan. It referenced Long Lehao’s "Three Gorges Dam in space" analogy and compared global SBSP efforts.

  
  

• Global Times - An April 23, 2023, article, "China to build gigawatt-level space power station: leading expert," offered earlier context, detailing a gigawatt-level station by 2050 and milestones like the Xidian University ground verification system. It cited Li Ming from the Chinese Society of Astronautics.

  
  

• Forbes - A March 5, 2019, article, "China Plans To Build The World's First Solar Power Station In Space," provided historical context, noting initial plans for a 200-tonne station by 2035 from the China Academy of Space Technology, with testing in Chongqing’s Bishan district.

  
  

• Popular Mechanics - Dated March 12, 2025, "China Is Building a Solar Station in Space That Could Generate Practically Endless Power" reinforced the project’s scale and ambition, linking it to China’s broader space goals, like lunar missions, and the CZ-9 rocket development.

  
  

• Science and Technology Daily (via China Daily) - Referenced in Forbes, this official Chinese source from 2019 confirmed early intentions to test microwave transmission using tethered balloons at 1,000 meters, with Pang Zhihao from CAST discussing the 36,000-kilometer orbit.

  
  

These sources collectively paint a picture of a project with real backing from Chinese state institutions, including the Chinese Academy of Engineering and CAST, with tangible steps like ground tests and rocket development.