MOSCOW (Rosatom PR) — The Russian Space Systems holding (part of the Roscosmos State Corporation) has developed a project for a promising solar space power plant (SCES). It is designed to supply power to hard-to-reach – island, mountainous and northern – regions of the Earth, as well as for scheduled and emergency recharging of spacecraft.
How does a space solar station differ from those familiar to everyone on the ground? In the Earth’s atmosphere, the sun’s rays are scattered and partially lose their energy efficiency. In outer space, the efficiency of using solar energy is ten times higher. RCS scientists proposed to convert it into a laser beam and transmit it to Earth with minimal energy loss.
According to the project, the SCES consists of two segments. The first, transmitting module is an unmanned spacecraft with an area of 70 m2 which accumulates the energy of the Sun and transmits it to the Earth. The second receiving module is a system of ground-based rectennas (mobile antennas) with batteries that receive solar energy from the spacecraft via a laser channel, convert it into electricity and distribute it to consumers. The advantages of laser energy transfer are fast translation (from a nanosecond) and extremely low beam divergence. The transmitting module can also serve as an orbital charging station – to transfer the accumulated energy to space satellites for operational recharging.
The station operates according to the scheme of separate energy storage: the collector receives solar radiation, and it is distributed in two directions. About 5% goes to the supply battery that powers the SCES itself. The remaining 95% are transferred to a storage battery designed to transmit energy to Earth. There is also a buffer for the accumulation of solar energy, which is activated when the supply and storage batteries are overfilled. At any time, this buffer electrical energy can be directed through a cyclotron converter to a ground-based rectenna with a laser.
The development was initiated in 2012 by Maria Barkova, a research engineer at the Advanced Equipment Development Department of the RKS.
“The problem of energy storage in orbit arose long ago. Back in the 1920s, Valentin Glushko proposed to build a helio-rocket plane, a spacecraft powered by solar energy. The basic concept of a solar space power plant was proposed by Peter Glaser in the 1960s. Today, this topic has become especially relevant: on the one hand, there is a search for safe and environmentally friendly energy sources that are not related to fossil resources – oil, gas, coal, on the other hand, there is a need to develop hard-to-reach territories for their development and inclusion in the economic and infrastructure system”.
The project involves the creation of low power SCES (up to 100 kW per broadcast). Energy accumulates for quite a long time: 600 MW will have to wait a month and a half – or create a large constellation of spacecraft, and this is expensive.
“SKES will find it difficult to compete with traditional ways of generating energy: thermal power plants, hydroelectric power plants, nuclear power plants,” said Maria Barkova. “But it can be useful in remote areas of Russia, where the use of traditional methods of generating energy will be fraught with the difficulties of building and delivering fuel.”
It is assumed that space power plants will be in sun-synchronous orbits with an inclination of 82°, 90° and 98°. Accurate targeting of the laser beam to mobile ground-based rectennas will be provided by a synchronizing software package.
The developers have prepared a feasibility study for the creation of SCES. According to their estimates, the pilot station, consisting of one spacecraft and one rectenna, will pay off within 20 years, and the energy received at it in hard-to-reach areas will cost 2-6 rubles per 1 kWh. Regional authorities are considered as a potential customer at the initial stage.
The RKS station has competitors. For example, China is developing a project for a large station in geostationary orbit. But Russian scientists believe that collecting it in space would be too expensive. The Japanese propose to create a SCES in a low-stationary orbit, which will transmit energy to the Earth via microwave waves. The RCC says that this will be ineffective: the microwave has a greater beam divergence than the laser, which is fraught with large energy losses.