According to China's state-backed Science and Technology Daily, Chinese scientists plan to build and launch small power stations into the stratosphere between 2021 and 2025, with a megawatt-level station planned for 2030 and a gigawatt-level facility before 2050. Without interference from the atmosphere or seasonal and night time loss of sunlight, these space-based solar farms could provide an inexhaustible source of clean energy, with the China Academy of Space Technology Corporation claiming such a set-up could reliably supply 99 percent of time at six times the intensity of solar plants on Earth.
There are, of course, numerous challenges associated with this sci-fi-sounding plan. Such a power station would weigh a considerable amount -- around 1,000 tonnes -- so getting the gear into orbit will be difficult. Researchers are therefore considering whether the station could be constructed in space using robots and 3D printing. The effects of microwave radiation on the atmosphere will also need to be studied.
But it's clearly not beyond the realms of possibility. There's already a lot of research out there exploring this technology -- Japan has been talking about this for a decade, while space programs are constantly growing their understanding of the technology needed to effectively beam power back to Earth. Japan hit upon a solution in 2015 using wireless transmission, while the California Institute of Technology announced last year that it had created a prototype capable of harnessing and transmitting solar energy from space using lightweight tiles. China's proposal, meanwhile, appears to suggest converting solar energy into electric energy in space, before beaming back to Earth using a microwave or laser and feeding into the grid via a ground receiving system.
China has really ramped up its space program in recent times, reaching the far side of the moon and growing the first plants on the lunar surface. Its timescales for this plan may be ambitious, but its quest to become a space superpower suggests this common science fiction dream is closer than ever to becoming a reality.