China's ambition to build a 1MW solar power station in space

China is building a ground-based test facility for a solar power station, which transmits electricity to Earth through microwave beams.

With more than a third of the days covered in smog a year, the southwestern Chinese city of Chongqing is not an ideal place to build a solar power plant. But soon, the city will become the first to test a revolutionary technology that will allow China to send and receive powerful energy beams from space in a decade, according to scientists involved in the project.

Simulation of a solar power station in space. (Photo: People's Daily Online).

Using huge infrastructure in orbit to collect energy from the Sun and send it back to Earth is considered science fiction. However, according to the Chinese government's plan, a 1 megawatt (MW) solar power station will be put into space by 2030. In 2049, the total power capacity of the plant will increase to 1 gigawatt, equivalent to a furnace. largest nuclear reaction today.

After breaking ground in Hoa Binh village in Bich Son district, Chongqing, three years ago, the construction of a $15.4 million ground-based test facility for the space solar program had to be temporarily halted. stopped, in part due to controversy over the cost, feasibility, and safety of the technology. The project resumed in June. Zhong Yuanchang, a professor of electrical engineering at Chongqing University, said construction of the facility should be completed by the end of the year, meeting the tight deadline.

The powerful beam needs to penetrate the cloud layer efficiently, and transmit it directly and accurately to the ground station. Researchers at the Bich Son facility will seek to achieve that goal. Solar plants are inefficient because they can only operate during the day and the atmosphere reflects or absorbs almost half of the energy in light.

Since the 1960s, a number of space scientists and engineers have been intrigued by the idea of placing the Sun in space . From an altitude of 36,000km or more, the geostationary solar plant can avoid the Earth's shadow and be illuminated by the Sun 24 hours a day. The loss of energy in the atmosphere is also reduced to a minimum (about 2%) thanks to the transfer of energy in the form of high-frequency microwaves. Over the past few decades, many different designs of solar power stations have been proposed around the world, but only in theory due to major technological challenges. At Bich Son, Chinese researchers will need to demonstrate that wireless power transmission is feasible over long distances.

Although engineer and inventor Nikola Tesla made the idea popular in the late 19th century, the technology was limited to a few short-distance applications such as wireless charging for smartphones. Tesla failed in part because he let electricity travel through the air as waves in all directions. To increase the effective range, the energy needs to be concentrated into a high intensity beam. Chinese scientists collect wireless energy emitted from a balloon 300 meters above the ground. When the Bich Son facility is completed, they plan to increase the range to more than 20 km with a balloon that collects solar energy from the stratosphere.

At Bich Son, the team will also test a number of other applications of the technology, such as using energy beams to power drones. The central test area will be 2 hectares wide, surrounded by a safe zone 5 times larger. Local residents are not allowed to enter the buffer zone for their own safety.

The safety risk of solar plants in space is not small, according to some recent studies in China. For example, when giant solar panels rotate to face the Sun, they can generate small sustained pulses in the microwave beam gun, which can cause problems. As a result, the facility needed extremely complex flight control systems to maintain precise targeting of the Earth's microscopic spot.

Another risk is radiation. According to calculations by a team at Beijing Jiaotong University last year, residents cannot live within 5 kilometers of a ground-based receiving station. Even trains 10 km away can experience problems such as loss of communication due to the frequency of microwaves that can affect Wi-Fi.