With more than a third of days marred by fog all year round, Chongqing city in southwestern China is not the ideal place for a solar power plant. But soon it will have the nation’s first experimental facility to test a revolutionary technology allowing China to send, and receive, a powerful energy beam from space in about a decade, according to scientists involved in the project.
Harvesting energy from the sun and beaming it to Earth using huge infrastructure in orbit has been regarded as science fiction, but according to a plan by the Chinese government, the nation will put a 1 megawatt solar energy station in space by 2030.
And by 2049, when the People’s Republic of China celebrates its 100th anniversary, the total power capacity of the plant or plants would increase to 1 gigawatt, the equivalent of the current largest nuclear power reactor.
After breaking ground in Heping village, Bishan district, three years ago, construction of the 100-million-yuan (US$15.4 million) ground testing facility for the national space solar-power programme stopped, in part because of debates about cost, feasibility and safety of the technology.
The project resumed in June, according to the district government’s website.
Zhong Yuanchang, an electrical engineering professor involved in the project with Chongqing University, was quoted in the Beijing-based China Science Daily on Monday saying construction of the facility would be finished by the end of this year, meeting a tight deadline.
An intensive energy beam would need to penetrate the cloud efficiently and hit a ground station directly and precisely. Researchers at the Bishan facility will work on these and other projects.
A solar energy plant is not efficient because it only operates during the day, and the atmosphere reflects or absorbs nearly half the energy in the sunlight.
Since the 1960s, some space scientists and engineers have been attracted to the idea of a solar station in space. From an altitude of 36,000km (22,400 miles) or above, a geo-stationary solar plant can avoid the Earth’s shadow and see the sun 24 hours a day.
The energy loss in the atmosphere could also be reduced to the minimum (about 2 per cent) by sending the energy in the form of high-frequency microwaves.
Over the last few decades, various forms of solar power stations have been proposed from around the world but they remained theoretical because of major technical challenges.
At Bishan, Chinese researchers would first need to prove that wireless power transfer worked over a long distance.
Although the engineer and inventor Nikola Tesla popularised the idea in the late 19th century, the technology has been limited to only a small number of short-range applications, such as the wireless charger for smartphones.
Tesla failed in part because he made the electricity travel in the air like waves in all directions. To increase the effective range, the energy must be concentrated into a highly focused beam.
The Chinese researchers received wireless energy emitted from a balloon 300 metres (980 feet) above the ground. When the Bishan facility is complete, they plan to increase the range to more than 20km with an airship collecting solar energy from the stratosphere, according to the China Science Daily.