The Concept of Space-Based Solar Energy
The idea of harnessing solar energy in space has been around for decades, with its origins tracing back to the early 20th century. Science fiction writer Isaac Asimov was one of the first to envision a solar farm in space. In his 1941 short story “Reason,” he described two astronauts training a robot to operate a solar energy station in space that beams power across the Solar System.
In the 1960s, scientists began developing technologies for deploying space-based solar energy. Despite these early efforts, solar panels are still not orbiting above our heads today. The challenge lies in the complexity of building and maintaining such systems in space.
How Space-Based Solar Panels Work
Building solar panels in space involves several steps. First, the components are designed and constructed. These parts are then launched into orbit by rockets and assembled into a larger structure using robots. Once in place, the structure captures sunlight and transmits it wirelessly down to Earth.
This process is not easy, but Sanjay Vijendran, co-founder and CTO of TerraSpark, a European private company specialising in space-based solar energy, believes the potential is remarkable. He stated that going up into space where the sun is shining 24/7 allows for capturing clean energy in a reliable way that is available for the next five billion years.
However, despite the promise, no one has managed to implement this technology yet due to the immense complexity involved.
The Debate Around Space-Based Solar Energy
NASA, the American space agency, concluded in 2024 that the two space-based energy systems it analyzed were extremely expensive and may produce greenhouse gas emissions comparable to existing renewable energy systems. This has sparked debate among experts regarding the necessity of pursuing this approach.
Francesco Contino, professor at UC Louvain, Belgium, expressed concerns about the direction of this technology. He suggested that society should focus on sufficiency rather than exploring new ways to get more energy. On the other hand, Wei He, senior lecturer in engineering at King’s College London, offered a more balanced view. His study suggested that space-based solar power could reduce Europe’s need for land-based renewable energy by up to 80 per cent.
He acknowledged the great potential of this technology for decarbonisation but also highlighted the risks associated with long-term returns.
ESA's Solaris Project
While private companies like Vijendran’s are investing in this technology, space agencies continue to emphasize the need for further development before deployment. At the end of 2022, the European Space Agency (ESA) launched Solaris, a three-year research and development programme aimed at preparing Europe for future decision-making on space-based solar energy.
The programme generated interest and curiosity from the public and international media, with Vijendran working as one of the main leaders. However, as Vijendran explained, the agency found the technologies still relatively immature for moving to the next step of a demonstration mission.
The decision was made not to pursue Solaris in the way it had been imagined, instead focusing on developing the technologies further. Vijendran noted that the Solaris project ended around August 2024.
Both studies commissioned by ESA consider space-based solar power a promising perspective to address terrestrial energy needs. Specifically, the study conducted by Arthur D. Little raised questions about debris collision risks, public acceptance, and the substantial financial investment required. The report by Thales Alenia Space Italy foresees an enhancement of the economic and technical viability of the project through new technologies, but calls for further research and international cooperation.
