Solar Energy Could Power the Earth from Space

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solar energy

Solar energy farms are being seen in more and more locations around the globe as governments worldwide strive to undergo a green transition. Thanks to significant public and private investment into solar panel technology in recent decades, the technology has progressed significantly to allow solar power to be produced in a wide range of locations. Now, scientists believe they may have cracked to code space-based solar power using power stations capable of beaming solar energy to Earth. 

Space-based Solar Power

While solar energy projects have become cheaper and much more efficient in recent years, there are still significant limitations to producing solar power. Solar panels can only produce energy during daylight hours and rely heavily on batteries to store any excess energy to deliver to the grid at night. This means that there is no stable supply of energy provided by solar farms without the use of expensive, high-tech battery storage. Further, the sunlight on the Earth’s surface is far less intense than that at the top of the atmosphere. 

The potential for generating far higher levels of solar energy has led scientists worldwide to explore the possibility of space solar power over several decades. Researchers found that if they could access solar power at a high enough orbit, it could provide continuous power from sunlight that could be beamed to stations around the globe. The idea is to transform solar power into electricity using photovoltaic (PV) cells in a geostationary orbit around Earth. This power can then be transmitted wirelessly in the form of microwaves at 2.45 GHz to dedicated receiver stations on Earth, called ‘rectennas’, which convert the energy back into electricity and deliver it to the local grid.

As well as reducing the amount of land required for solar farms, these systems could serve remote parts of the world, providing rural communities with a stable, green energy supply. However, the technology is not yet available to launch such a project, and significant research and development is required to overcome the technical obstacles involved. 

U.S. Solar Space Developments

In January 2024, NASA published a report entitled ‘Space-Based Solar Power’ focused on how NASA might support the development of this field of research. Charity Weeden, who leads NASA OTPS stated, “This analysis compares the lifecycle cost of two conceptual space-based solar power systems versus their potential for net emissions reductions. Weeden added, “By considering scenarios like these, OTPS helps NASA understand the technological, policy, and economic implications that would need to be addressed.”

The report assesses the ways in which solar power generated in space could be competitive when it comes to achieving net-zero greenhouse gas emissions compared to other green energy options. It also considers NASA’s potential role in the field. 

While there is optimism around the potential generation of solar power from space, several capability gaps must first be addressed. Scientists must figure out how to assemble and maintain large systems in orbit, enable those systems to operate autonomously and develop efficient power-beaming to bring the harvested energy to Earth. They must also assess how viable it is for these systems to operate in geostationary orbit compared to low-Earth orbit, where many satellites operate at present. In addition, it is important to fully assess the costs involved with transporting huge infrastructure into space and running solar space projects. 

NASA is currently developing technologies that could indirectly support space-based solar power systems including autonomous systems, wireless power beaming, and in-space servicing, assembly, and manufacturing.

Progress Elsewhere

In the U.K., several institutions are assessing the potential for launching solar space projects. A 2023 study from the Universities of Surrey and Swansea found that it is viable to produce low-cost, lightweight solar panels that can generate energy in space. The study followed a satellite over six years and observed how the panels generated power and weathered solar radiation over 30,000 orbits. The researchers believe the findings from the study could pave the way for commercially viable solar farms to be developed in space. 

Professor Craig Underwood at the Surrey Space Centre stated,We are very pleased that a mission designed to last one year is still working after six. These detailed data show the panels have resisted radiation and their thin-film structure has not deteriorated in the harsh thermal and vacuum conditions of space.” Underwood added, “This ultra-low mass solar cell technology could lead to large, low-cost solar power stations deployed in space, bringing clean energy back to Earth — and now we have the first evidence that the technology works reliably in orbit.”

Meanwhile, Scientists at the California Institute of Technology achieved a successful test flight of technology that could generate power from space. The Space Solar Power Demonstrator (SSPD-1) mission was a small-scale test of the technology needed for the potential power stations in space. After launching in January 2023, the SSPD-1 spent a year evaluating different solar cells and deployment methods and, in March, became the first technology to wirelessly beam power to Earth from space. The success of this mission shows great promise for the future of solar space power. However, it is important to note that it was a small-scale mission and there are still significant technical hurdles to overcome to achieve commercial solar power production in space.

Felicity Bradstock is a freelance writer specializing in Energy and Industry. She has a Master’s in International Development from the University of Birmingham, UK, and is now based in Mexico City.

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