Is space-based solar power the future of energy?

Imagine a power station orbiting high above Earth, soaking up the Sun's rays without a single cloud to block them — and then beaming that energy straight down to our homes and cities.

For decades, this vision lived in the realm of science fiction. First proposed in 1968, space-based solar power was dismissed as too costly, too complicated, and too far-fetched to pursue. But as the world scrambles to meet net-zero goals, the idea is staging a comeback.

Advocates argue it could deliver clean energy day and night, reducing the need for vast wind and solar farms on Earth. Sceptics, however, warn that the technical hurdles and enormous costs may keep it grounded forever.

Why space?

Solar panels on Earth face an obvious problem: the Sun sets. Clouds, rain, and seasonal shifts also cut efficiency. Space-based panels would avoid these limits. Orbiting satellites could face the Sun almost continuously and collect far stronger solar radiation than panels on the ground. In theory, they could deliver electricity day and night, in summer and winter.

The captured energy would not be sent down through physical wires. Instead, it would be converted into microwaves and beamed to receiving stations on Earth. From there, it would enter the grid like any other source of power. It is the same principle that allows satellites to transmit communications, only scaled up to deliver electricity.

New research suggests that such systems could supply Europe with steady energy at far lower storage requirements. A recent study predicted a 70 per cent reduction in the need for large batteries, which are currently one of the biggest bottlenecks for renewable power.

Competing designs

NASA has studied two main designs. One is the so-called heliostat swarm, which uses thousands of reflectors to focus sunlight onto a central receiver. It could, in theory, operate 99 per cent of the year. By 2050, it might even outperform wind and solar power on Earth, which could cut total grid costs by as much as 15 per cent.

The other option is a planar array, a more traditional design with flat panels that face the Sun. It would only generate power about 60 per cent of the year, but it is far closer to being technically feasible now. Researchers see it as a stepping stone: a way to test and refine the concept while waiting for the heliostat approach to mature.

Either design would mark a leap forward from terrestrial panels, which typically manage an efficiency of 15 to 30 per cent. However, the challenge is whether nations are willing to invest enough to bring these designs into orbit.

The hurdles to face

Even the most optimistic models are hedged with conditions. For the heliostat design to be cost-effective, its costs would need to fall to about 14 times those of ground solar by mid-century. The planar array would need to come down to nine times the cost. Current figures are at least ten to a hundred times higher.

Beyond cost, there are practical barriers. Beaming power across space and atmosphere is still largely untested at scale. Vast orbital structures would have to be built and maintained by autonomous robots, a technology that does not yet exist outside experimental settings. Then there are risks that are harder to model: debris collisions, system degradation, or disruptions to the transmission beam.

These concerns explain why space solar power has remained a "blue-sky" idea for decades. But that is beginning to change. Researchers are now embedding it into long-term energy planning. Policymakers in China, Japan, the United States, and Europe are pushing for test projects, signalling a seriousness that did not exist even ten years ago.

A possible future

Europe's net-zero goal for 2050 requires vast amounts of renewable energy. Land-based solar and wind have grown rapidly, but they face limits of geography, storage, and reliability. Space-based solar offers a centralised option that avoids many of those pitfalls. The study led by King's College London suggests it could replace up to 80 per cent of Europe's current need for ground-based renewables.

But at the same time, it is also a gamble. The pace of cost reduction in rocket launches, robotics, and wireless transmission will decide whether it becomes a pillar of the energy mix or remains a niche experiment. Nations like China argue that without state-led strategies, they risk falling behind. The United States and Japan are already testing small-scale demonstrations.

The truth is that space-based solar power sits at a crossroads. It is neither a fantasy nor a guarantee. It could provide round-the-clock clean power to billions, or it could collapse under its own complexity and expense. But for now, it is a bet on whether humanity can solve two problems at once: the climate crisis on Earth and the technological hurdles in space.