China re-iterates plans to build a Three Gorges Dam in space

Go to a conference on the future of energy, or most topics for that matter, and countries announcing that they’re going to start building solar power stations in space inevitably crops up so it seems that space based solar power stations are the next big thing. But in true fashion China is trying something bolder and bigger than anyone else.

China has reportedly announced an ambitious plan to build large-scale solar power stations in space with the help of super-heavy rockets. The South China Moring Post (SCMP) reported that a senior rocket scientist, Long Lehao, is leading this ambitious endeavour. He likens this project to “another Three Gorges Dam project above the Earth.”

The Three Gorges Dam, based on the Yangtze River, is China’s world’s largest hydropower project. It has an annual power generation capacity of approximately 100 billion kilowatt-hours.

“We are working on this project now. It is as significant as moving the Three Gorges Dam to a geostationary orbit 36,000km (22,370 miles) above the Earth. This is an incredible project to look forward to,” Lehao, a member of the Chinese Academy of Engineering (CAE), stated during a lecture hosted by the Chinese Academy of Sciences (CAS).

The lecture took place in October, but the transcript of his speech was made available by the academy on December 28.

Several countries, including the US and the UK, are exploring this field. Like the Manhattan Project, this initiative is seen as a major undertaking with the potential to boost the renewable energy sector rapidly.

A key benefit of space-based solar power is continuous operation, unhindered by weather, day-night cycles, or seasonal variations. Moreover, the intensity of sunlight reaching a surface in space is much greater than the intensity of sunlight reaching the Earth’s surface.

Long envisions “installing a solar array 1km wide along the 36,000km geostationary orbit,” with “the energy collected in one year being equivalent to the total amount of oil that can be extracted from the Earth,” he stated.

The placement of the array in a geostationary orbit will ensure it remains stationary relative to Earth, optimising sunlight exposure and simplifying the task of beaming energy back to anywhere on Earth.

The success of this space-based solar power project hinges on powerful rocketry. Long and the team are working on the development of the Long March-9 (CZ-9), a reusable heavy-lift rocket.

This massive rocket is currently under development in China and could be a global leader in heavy-lift capabilities. With a capacity exceeding 150 tons to orbit, it surpasses even NASA’s most powerful rockets, such as Saturn V and Space Launch System (SLS) - China is not just dreaming about the future. The country is already testing crucial technologies.

In June 2021, China initiated the construction of its first experimental space solar power station in Bishan. Then, in November 2023, researchers from the Xian University of Electronic Science and Technology published test results for the “Chasing Sun Project,” the world’s first complete ground verification system for space solar power.

Reportedly, this system demonstrated world-leading performance in microwave power transmission, beam collection efficiency, and power transfer efficiency. However, Long’s ambitious project may take years to become a reality.

Up until now US companies have been leading in this emerging sector with companies like Lockheed Martin and Northrop Grumman actively developing and testing space-based solar power technologies with the US military. The California Institute of Technology has also been involved in research and development related to space-based solar power, contributing to advancements in key technologies and, interestingly, Japan is planning to test its own space-based solar power station later this year.