The future of clean energy may be out of this world—literally.

Researchers around the globe are racing to turn space-based solar power, an idea once dismissed as science fiction, into a practical tool for delivering constant, carbon-free electricity back to Earth.

The concept is ambitious but deceptively simple: launch massive solar arrays into orbit, harvest the sun’s energy 24 hours a day, and beam that power wirelessly to ground-based receivers.

Unlike terrestrial renewables, which vary with weather and daylight, a space-based system can provide continuous power in all climate conditions. It is location-independent and could deliver uninterrupted power anywhere in the world: cities, disaster zones, remote islands, even future bases on the Moon or Mars.

Why Space?

Fossil fuels have dominated global energy production since the Industrial Revolution, with unintended environmental consequences.

Terrestrial solar and wind farms offer cleaner alternatives, but they require land, face intermittency challenges, and depend on vulnerable ground-based grids. Space-based solar power promises many of the same climate benefits without the constraints of weather, seasons, or sprawling land use.

It also offers strategic advantages; because power can be steered where needed, it could strengthen energy security for nations reliant on imports or prone to natural disasters.

Because national grids typically reach major urban centers first, remote and underserved regions are often left behind, leaving millions without the electricity that could fundamentally improve daily life. Current estimates indicate that between 730 million and 1 billion people (roughly 12 percent of the global population) still lack reliable access to power. Space-based energy systems, capable of beaming electricity directly to isolated areas, could help bridge this gap.

A Global Race

Several countries—most notably the United States, the United Kingdom, Japan, and China—have launched programs to test and eventually deploy orbiting solar power systems.

Japan has been a quiet but persistent leader. For decades, the Japan Aerospace Exploration Agency (JAXA) has invested in its Space Solar Power Systems (SSPS) program, which aims to convert sunlight into microwave or laser energy and transmit it to Earth.

In a statement, the agency highlighted key strengths: 

“The SSPS has many advantages as follows: it provides power 24 hours a day without being affected by weather conditions, unlike terrestrial renewable energy sources; the solar irradiance in space is 40% stronger than that on the ground; power can be directed to different locations on demand; as the SSPS eliminates the need for power lines, it is less vulnerable to terrestrial natural disasters; and solar energy is not affected by fluctuations in energy prices, unlike fossil fuels.”

Japanese scientists plan to test their OHISAMA (“sun”) satellite by the end of 2025. The 400-pound craft carries a solar panel approximately 22 square feet and is expected to beam roughly one kilowatt of power, enough to run a small home appliance, to Earth during its first demonstration.

In the United States, momentum has also been building. In 2023, researchers at the California Institute of Technology (Caltech) successfully transmitted power from orbit using a microwave beam in an experiment known as MAPLE (Microwave Array for Power-transfer Low-orbit Experiment).

“Through the experiments we have run so far, we received confirmation that MAPLE can transmit power successfully to receivers in space,” Hajimiri said in a statement. “We have also been able to program the array to direct its energy toward Earth, which we detected here at Caltech. We had, of course, tested it on Earth, but now we know that it can survive the trip to space and operate there.”

The U.K. has also positioned itself as a significant player in the emerging space-based solar power sector, backing the technology with multimillion-dollar investments. Early estimates suggest these systems could supply up to 80 percent of Europe’s renewable energy needs. Institutions such as Cambridge University and Queen Mary University of London are among those advancing core elements of the technology.

A 2021 analysis projected that a national space-based power program could generate roughly 143,000 jobs across the U.K. and ultimately meet up to a quarter of the country’s electricity demand. This economic and energy opportunity has captured growing attention among policymakers.

“I want the UK to boldly go where no country has gone before—boosting our energy security by getting our power directly from space,” Secretary of State for Energy Security and Net Zero Grant Shapps said.

“We’re taking a giant leap by backing the development of this exciting technology and putting the UK at the forefront of this rapidly emerging industry as it prepares for launch,” he added. “By winning this new space race, we can transform the way we power our nation and provide cheaper, cleaner, and more secure energy for generations to come.”

Promise and Peril

The U.S. Department of Energy has described space-based solar power as a technology that “may arrive sooner than you think.” Its proposed systems would orbit 35,000 kilometers above Earth and could one day deliver enough electricity to power a large city. Officials point to relatively manageable startup costs—between $500 million and $1 billion—and designs in which satellites would self-assemble, reducing risk and labor.

But challenges remain, the DOE stated. Receivers on the ground would need to span several kilometers. Lasers, while promising for transmission, raise safety and security concerns, particularly the threats of blinding and weaponization. And satellites positioned so far from Earth would be difficult, if not impossible, to repair.

A 2024 NASA report further underscored the hurdles: the enormous number of rocket launches required, the uncertain climate impact of rocket emissions released at high altitudes, potential interference with radio frequencies, and the increased risk of orbital debris. None of these issues is insurmountable, the agency noted, but each will require international coordination and regulatory adaptation.

Recent Breakthroughs

Despite the obstacles, U.S. federal agencies are pushing forward.

In May, the Defense Advanced Research Projects Agency (DARPA) announced it had set a new record for space-to-Earth power transmission, delivering more than 800 watts of energy during a 30-second laser test from 8.6 kilometers away, far surpassing previous benchmarks. DARPA said the work is part of a long-term goal to create systems capable of delivering instant, fuel-free power, potentially transforming both civilian and military logistics.

The idea of space-based power systems is not new.

Nearly 60 years ago, Peter E. Glaser, a NASA engineer and project manager for Apollo 11, patented the first concept for a solar power satellite. “He was granted a patent on the Solar Power Satellite to supply power from space for use on the Earth,” according to the National Space Society (NSS).

At the time, the technology to deploy such a system was far beyond reach. Today, the physics remains the same, but advances in materials, robotics, and wireless transmission have finally brought the concept within sight of feasibility.

The Path Forward

Whether space-based solar power becomes a cornerstone of global energy strategy will depend on factors such as economics, geopolitics, environmental impact, public trust, and security concerns.

But its potential—clean, constant, flexible power delivered anywhere on Earth—offers a compelling incentive for continued research and development.

What once seemed like an audacious dream is inching closer to reality. The world’s energy future may soon depend not just on the sun, but on our ability to capture it from space.

The views and opinions expressed are those of the author’s and do not necessarily reflect the official policy or position of C3.