Solar Energy for the Darkest Places on Earth
The whole world is in alarm state due to the coronavirus pandemic. Social networks and most of the media are full of negative headlines and keep frightening us with disappointing forecasts. Nevertheless, there is a lot of positive news. Science does not stand still and continues to develop future technologies for the benefit of humanity. Russian scientists from the Moscow Radiotechnical Institute of Russian Academy of Sciences have patented a system for transferring energy from a space – based solar power station to Earth. It is expected that a solar power system will be able to transmit energy using microwaves to the remote areas of the planet, where it is impossible to lay ground power lines. The Global Energy Prize experts have shared their opinion on possibility of construction that kind of solar power plant.
Scientists from all over the world have been interested in the idea of building a space – based solar power station for a long time. In 1941, science fiction writer Isaac Asimov published the short story ‘Reason’, in which a space station transmits energy collected from the Sun to various planets using microwave beams. And in 1973 Peter Glaser realised this idea. He was granted U.S. patent number 3,781,647 for the method of transmitting power over long distances using microwaves from a very large antenna on the satellite to a much larger one on the ground. Despite the fact that the development of the technology had begun a long time ago, radically new solutions have not appeared lately. In this regard, Martin Green, the 2018 Global Energy Prize laureate, Professor of School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, notes: ‘I suspect the new patent must deal will the particulars of how the power is transmitted or received. Most previous suggestions have been that the power station be placed in geosynchronous orbit (35,786 kilometers high) so it remains fixed above a point on Earth, rather than an altitude of 300 to 1000 kilometers.’
According to Boris Katorgin, creator of the rocket engine RD-180, the 2012 Global Energy Prize laureate, full member, Russian Academy of Sciences, creating a solar power plant able to accept power for operation on orbit is not a short-term matter. First of all, it is necessary to overcome a number of scientific and technical problems: to create super-heavy carrier rockets for launching large-sized elements of power plants into low earth orbit; to develop a technology for a safe and high-quality assembly of large-sized structural elements; to increase significantly the efficiency of converting solar energy into electrical and electrical energy into microwave or laser radiation. The scientist also recommends to study carefully the issue of negative pollution of the atmosphere and the surface of the earth's crust with high-power electromagnetic radiation.
Despite the fact that technical solutions for creating space – based solar power plant aren’t ripe yet, David Faiman (Israel), the Global Energy Prize International Award Committee member, Professor of the Ben-Gurion University of the Negev, considers generating electric power from the Sun in space in an earth orbiting satellite to be a very exciting prospect. According to the scientist there are three reasons for that. First of all, because there is no atmosphere to dilute the sun’s rays, the satellite actually sees sunlight about 50% stronger than earthbound solar panels would see it. Secondly, satellite sees the Sun for 24 hours a day except for the few minutes every day when Earth passes between the panels and the Sun. And thirdly, what the satellite generates really is constant, because there's no sunrise and sunset in space and no clouds to make the output stronger or weaker every time clouds pass.
However, David Faiman also emphasises a number of critical aspects directly related to the safety of human life: ‘There is the question of making sure that no aircraft accidentally fly through the microwave beam because it's very powerful, much more powerful than a microwave oven at home. And, finally, one has to employ some kind of completely failsafe mechanism so that if the satellite is hit for example by a passing meteorite the microwave beam doesn't spill off and into some dangerous place where there are humans.’
Along with the technological difficulties of the project, experts note the presence of economic difficulties. Michael Graetzel, professor at the Swiss Federal Institute of Technology, the 2017 Global Energy Prize laureate considers the high cost of the project to be the main obstacle for launching the station: ‘The disadvantage at this time is the big, very big cost for launching. It would have to come down to two hundred dollars a kilogram and that's to all of the magnitude lower than what it cost today as just rocket launches the material.’
American professor Khalil Amine, the 2019 Global Energy Prize laureate, an Argonne Distinguished Fellow and the Manager of the Advanced Lithium Battery Technology Group at Argonne National Laboratory, proposes to provide energy to remote regions of the world using isolated low cost solar panels with power banks as an alternative option to the space – based systems: ‘This technology is low cost! One can imagine powering a whole village using a single station with power banks!’
It can therefore be concluded that the concept of launching a space – based solar power station is feasible. But the question of whether the cost of solving all technological problems together with the cost of launching a satellite into space can be comparable with the cost of building a simple array of solar panels on the ground remains open.