As researchers frantically search for new sources of clean power to meet the rising power demand on earth, the sci-fi idea of space-based solar power is finally taking shape to become a reality. It was science fiction writer Isaac Asimov who, in his science fiction story Reason in 1941, had first talked about a space station transmitting energy collected from the Sun to various planets using microwave beams. The concept makes such a strong case for solving the energy crisis on earth that countries like USA, China and Japan are pushing ahead with their plans to tap space solar power.
California Institute of Technology (Caltech) has launched Space Solar Power Initiative (SSPI) with the goal of generating electricity from sunlight in space as cheaply as fossil-fuels. Funded by aerospace company Northrop Grumman Corporation, the initiative will focus on innovations for enabling a space-based solar array system, consisting of ultralight, high-efficiency photovoltaics, a phased-array system to produce and distribute power dynamically, and ultralight deployable space structures.
The space solar power station being planned by China, if realised, would be the largest-ever space project. The power station would be a super spacecraft, on a geosynchronous orbit 36,000 km above the ground, equipped with huge solar panels. The electricity generated would be converted into microwaves or lasers, and transmitted to a collector on Earth—reports Chinese Academy of Sciences.
Wang Xiji, an academician of the Chinese Academy of Sciences and an International Academy of Astronautics member, believes Asimov’s fiction has a scientific basis. “An economically viable space power station would be really huge, with the total area of the solar panels reaching 5 to 6 sq km. Maybe people on Earth could see at night, like a star,” says Wang.
Japan too has similar plans. The spacecraft being developed by researchers at the Japan Aerospace Exploration Agency and Japan Space Systems will have a square screen of solar panels measuring more than 1.2 miles along each side and use microwaves to beam energy down to Earth—reports Telegraph.
Inching a step closer to realization of space solar power transmission to earth, Japan Space Systems recently successfully tested wireless transmission of electricity. In the experiment, a total of 1.8 kilowatts of electricity was converted into microwaves, transmitted to a two-square-meter antenna panel 55 meters away and converted back into electricity.
Given that the cost of generating solar power here on earth is going down fast and, in many countries, now equals that of fossil fuels, one may wonder “why go to space then for harnessing the solar power.” To answer this question, it’s important to look at the many advantages of space-based solar power vis a vis ground-based solar.
According to the National Space Society, an American international non-profit organization specializing in space advocacy, “Unlike terrestrial solar and wind power plants, space solar power is available 24 hours a day, 7 days a week, in huge quantities. It works regardless of cloud cover, daylight, or wind speed. Space solar power can provide large quantities of energy to each and every person on Earth with very little environmental impact. The solar energy available in space is literally billions of times greater than we use today. The lifetime of the sun is an estimated 4-5 billion years, making space solar power a truly long-term energy solution. As Earth receives only one part in 2.3 billion of the Sun’s output, space solar power is by far the largest potential energy source available, dwarfing all others combined.”
Saving of valuable real space on earth and freedom from cable clutter in households are two other major factors that work in favour of space solar power.
However, there are challenges to overcome before space solar power becomes feasible—high development and deployment cost tops the list. There is need to develop super-light, super-efficient solar cells and structures, as also low-cost, environmentally-friendly launch vehicles. Considering that solar power satellites must be large to collect massive quantities of energy, large-scale in-orbit construction makes sense.
Summing up in the words of the National Space Society: “Space solar power can completely solve our energy problems long term. The sooner we start and the harder we work, the shorter “long term” will be.” With successful testing of wireless power transmission and increasing funding for space solar projects, a beginning has already been made towards fruition of space solar power!
Written By: Uma Gupta, Contributing Author for Technology.Org