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Solar energy in space: China is leading innovation with an ambitious project to collect solar energy in space and transmit it to Earth. Learn more about this technology and its challenges
Solar photovoltaic energy is one of the most promising renewable energy sources for reducing our dependence on fossil fuels. At the path to sustainability, we have developed numerous projects that seek to harness the inexhaustible electromagnetic radiation of our sun to generate electricity. From the largest solar farm in the world to installing panels in our own homes.
However, our technological resources to make the most of solar photovoltaic energy are far from ideal. The panels that we install in different parts of the planet —even far from land— have a major disadvantage: they are affected by the attenuation of solar radiation from the atmosphere and by night phases. In other words, it is not a constant energy source, as marine energy is.
The idea of setting up a solar farm in space
So why not collect solar energy in space and send it to Earth? This idea, which seems straight out of science fiction, has been circulating for several decades. The United States was a pioneer in exploring this type of alternative in the 1970s, allocating an initial budget of 80 million dollars to study its feasibility and encouraging NASA with different projects.
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China, in turn, began working on space solar power (SSP) technology in 2012. Later, in 2015, the Chinese Academy of Space Technology (CAST) presented a roadmap to develop the project. This established that, in 2035, it would launch a 200-ton SSP station with a generation capacity of several megawatts.
The first tests of energy generation and transmission from orbit should have started in 2030, but according to the South China Morning Post, an article published in the Chinese Space Science and Technology magazine shows the updated plans of the Asian giant, which intends to begin testing two years earlier than originally planned.
China takes this idea seriously
But this is not just a simple declaration of intent. China appears to be taking this idea seriously, despite all the challenges ahead. According to the Eurasia Times, the country is already building a receiving station in the city of Chongqing to help with research into its ambitious project, and has already carried out energy transmission tests from aerostatic balloons.
The updated plans include the first satellite to test SSP being launched this year. It will have the capacity to supply enough energy to meet the energy needs of a few homes. However, researchers are still not sure which transmission method to use, microwave or laser, as each has its pros and cons.
The system could use a microwave energy transmitter
In the case of microwaves, researchers believe that this alternative could maximize the system's efficiency, preventing energy from being lost into the atmosphere. However, they are not sure whether this could negatively affect people's health. Because of this, an exclusion zone of several hectares would be established around the receiving station.
Furthermore, this alternative would require an antenna several meters (perhaps kilometers) in diameter in orbit and a receiving antenna of about 10 kilometers on Earth. It is believed that gravity or solar winds could cause movements that interrupt the transmission of energy.
If all goes well, after the first launch, other satellites would be launched to complete a huge solar station in orbit. China expects that by 2035 the system will be capable of producing 10 MW. By 2050, capacity is expected to increase to 2 GW.
Challenges and future prospects
The plan, although extended in time, seems very ambitious, but it is not free from major challenges that it needs to overcome. “Such a large infrastructure in space could upset many countries, especially those without the technology or capacity to build one,” points out Dong Shiwei, from the National Science and Technology Laboratory of the Chinese Academy of Technology.
It is worth noting that China is not the only country interested in exploring the possibilities of SSP. The UK plans to have its first 30 GW space solar power plant operational by 2040 to “supply 30 percent of the country’s electricity demand.” Over time, we will know whether these proposals can succeed.
