Solar energy is the fastest-growing domain that holds massive potential for fulfilling our energy needs both in an environmentally friendly and sustainable manner. With advancements in technology and affordability, many ways have been introduced to use solar power. But these methods have some limitations too. Solar panels can only generate power during the daytime. If clouds block sunlight, then no rays will be absorbed by the panels for energy production. Many space agencies and organisations from different countries are competing with each other to develop technology to combat this issue. They are working on a concept called Space-based Solar Power (SBSP) to address our energy needs without limitations.
Concept Of SBSP
The term Space-based Solar Power (SBSP) was first coined by American Physicist Peter Glaser in 1968. SBSP is an idea for producing solar energy in space using solar power satellites and wirelessly transmitting it to Earth. The concept is helpful and can compensate for the energy demands of each country. Atmosphere and clouds are absent in space and about 30 per cent of solar energy is reflected into space by the atmosphere. Therefore, solar power satellites can collect huge amounts of sun rays to generate solar energy. Being advantageous, the concept has a drawback too. The cost of making SBSP models is extremely high. Different space organisations are putting their best foot forward to develop this technology at a lower price.
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Working Of Space-based Solar Power (SBSP) System
Space-based solar power system is based on known physics and existing technology. It consists of solar power satellites having lightweight panels and a system of mirrors. These mirrors and panels absorb sunlight and produce around 3.4 GigaWatt of electricity in the satellites. This electricity is converted into radio frequency microwave radiation having a frequency of 2.45 GHz. The radiation is then transmitted wirelessly onto the Earth. On the ground, receiver stations, also known as rectennas, are built which collect these radiations. These radiations are again converted into electricity. The electricity is then fed into the local grid.
Space Organisations Working On SBSP
Japan is a leading country in technology. In the 1980s, researchers were successfully able to transmit power using microwaves in space. Due to this, the country became the world leader in the space sector too. In 2009, a research team at Kyoto University was able to transmit power from an altitude of nearly 30 meters to a mobile phone on the ground. In 2015 and 2018, after refining their technology, the team transmitted power up to a distance of 50 meters. The study was led by Naoki Shinohara, a professor at Kyoto University. In the future, the team aims to attempt power transmission over longer distances ranging between 1 km to 5 km.
Currently, Japan Aerospace Exploration Agency (JAXA) is in partnership with a private organisation and working on SBSP technology. If all its experiments go well, then JAXA will attempt its first trial of this technology in the year 2025. If Japan successfully makes this SBSP model before other countries, it will make it an industry leader. Japanese researchers can negotiate for resources with other nations involved in space research.
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Besides Japan, Europe is also engaged in developing the SBSP system. As a part of the Solaris program, the European Space Agency (ESA) is working on a space-based solar power concept to meet the country’s clean energy demands and reach a net-zero target (balancing greenhouse gas emissions by absorbing an equivalent amount from the atmosphere) by the 2030s. Like other countries, Europe is also making a model with solar power satellites, glasses and solar panels to generate electricity in space. “Transitioning to clean energy is an urgent imperative and Europe has committed to achieving net zero emissions by the year 2050,” said ESA.
Other countries like the US and China have participated in this space race. The US has been examining SBSP since 1978. Its Naval Research Laboratory tested a power-producing satellite in space in 2020. And the Air Force Research Laboratory will also test a satellite similar to Arachne in 2024. On the other hand, China is developing test facilities and ground stations for the SBSP project. The country is planning to test a satellite in 2028 that will produce a power of 10 KiloWatt.
The Road Ahead
Though SBSP has potential benefits, installing it in the space will bring some changes too. One such challenge was the weight of the solar power satellites. But this issue has been solved by replacing the solar panels with ultra-light solar cells. The other challenge which needs to be tackled is the cost. Installing space-based solar power stations and transporting elements in space is difficult and expensive. To generate 1 GW of power with available solar technologies, a wide area of solar panels will be required. Also, installing these panels will cost more than $7.1 billion (1 trillion yen). Other challenges associated with SBSP are gas emissions during space shuttle launches, damage to solar panels and transmission of energy across larger distances.
With current technology, it is difficult to solve all these challenges. But with the improvement and evolution in technology, many of these challenges will get solved. The cost of manufacturing and space launches will decrease. Every country is advancing their technologies to make the SBSP project successful. If all goes well, space-based solar power technology can manage the world’s energy demand and supply.