The Chinese are reportedly working on experimental solar power stations that would be launched into space to generate electricity. Planned for launch as early as 2021, they will provide "an inexhaustible source of clean energy for humans,” reliably supplying energy “99 percent of the time, at six-times the intensity of solar farms on earth.” The final plan is a Megawatt-level space solar power station for 2030. Pang said technical challenges to be overcome include the weight of a power station, expected to be 1000 tonnes, greater than 400 tonnes of the International Space Station. Researchers are examining whether a space factory using robots and 3D printing technology could construct the power station in space, avoiding the need to launch a heavy structure from earth. Solar energy would be converted to electricity and a microwave or laser beam would transmit the energy to earth.