Solar energy is one of the leading renewable alternatives in the joint global energy transition. The current technologies we use to harness this power source limit how much humanity can siphon, but perhaps this is about to change at a revolutionary scale. Enter: space-based solar farms.
SOLARIS: Europe’s initiative to accelerate towards clean energy
As concerns about the climate crisis mount, many leading energy industry giants have pledged to reach net-zero emissions or carbon neutrality by 2050. Europe is among these giants, and the continent is setting the stage for global collaboration in the energy transition.
In 2023, the European Space Agency (ESA) began developing the concept for a space-based solar power plant. The initiative, christened SOLARIS, commissioned a study led by Thales Alania Space Italy and renewable energy company ENEL.
The purpose of this research was to develop an early definition of a space-based solar power system that would wirelessly beam solar energy to the Earth using radio waves, 24/7, and unaffected by our fluctuating atmospheric conditions and seasons.
The energy would be transmitted to strategically located receiving stations connected to the electrical grid. “The physics behind this design is already implemented in telecommunications, where satellites beam small amounts of energy in the form of radio-frequency waves from orbit to a receiving ground station,” leader of the SOLARIS initiative Sanjay Vijendran explained.
Vijendran added that the difference with the space-based solar power plant is that “the amount of energy transmitted and successfully collected would need to be far larger to make the venture viable.” If ESA greenlights the project, Vijendran foresees many technological obstacles to overcome.
A precursor that may remove the “intermittency of generation”
Alternative to harnessing solar energy via wireless transmission, the ESA is investigating another method that may be implemented prior to launching radio-frequency solar power satellites.
This method would see the deployment of large photovoltaic mirrors in space, that would reflect sunlight to existing solar farms on Earth, significantly boosting their efficiency, and ensuring a continuous supply of solar even when natural light levels are low.
The idea of using photovoltaic (PV) panels in space is not entirely unheard of. According to ENEL, the first use of PV panels dates back to the late 1950s in the Vanguard I spacecraft. The aerial vehicle used a panel of less than one watt to power its radio.
“Space-based solar panels are already very different from those on Earth,” Nicola Rossi, Head of Innovation at ENEL Group said, adding that the materials used for space-based solar panels allow the cells to harness “specific slices” that make up the solar spectrum.
“In this way, all of the solar spectrum is harnessed, and thus, much more energy is extracted than in terrestrial cells, which, because of the characteristics of silicon, capture only the red part of the spectrum,” Rossi explained.
While the physics to build the foundation of these innovations exists, all SOLARIS parties involved agree that these solar innovations bring many technological hurdles that account for the space, weight, and cost of assembling a space-based solar power plant.
According to ENEL, the station would weigh approximately 11,000 tons. “Today, each space launch can carry about 100 tons into orbit; so a power plant would need about 100 launches of materials from Earth to space,” Rossi estimated.
“The power plant would then be assembled in orbit, using remotely controlled robotic systems,” she added.
The future of SOLARIS as we currently know it
As previously mentioned, SOLARIS commissioned studies to investigate the viability of investing in a space-based solar power station. The research findings will help ESA make an informed decision, which we can expect will announced by the end of 2025. Indeed, it is a promising prospect.
It is also much-needed, as Vijendran highlighted, “The threat of the climate of crisis demands that we work together to explore alternative technologies to achieve carbon neutrality – and, if implemented, space-based solar power could play an integral role in addressing this energy challenge, beginning as early as the 2030s.”
