Imagine a massive orbiting solar panel 400 kilometers above our heads in low Earth orbit. All day long, absorbing sunlight and returning the energy to Earth in the form of electricity. This is the fundamental concept of space-based solar power, a new approach to clean energy and renewable energy. Engineers are testing the effects of placing panels in space, where there are no clouds, no bad weather or good weather, and no daylight and nighttime, instead of rooftops or huge fields.
A “super solar panel” that can generate about 120 kW of power is apparently already undergoing testing 400 kilometers above Earth, according to recent reports. Even though that amount is still insignificant in comparison to what a whole city needs, it is important because it suggests that space-based solar energy could one day replace ground-based solar power in cities or even provide electricity to isolated locations.
How a solar panel in space really works
A solar satellite‘s main benefit is that sunlight is stronger and more consistent in space. On Earth, solar panels must contend with the day-night cycle, rain, and clouds. A panel in 400 km of low Earth orbit spends the majority of its time in direct sunlight, only briefly passing through Earth’s shadow. This means it has almost constant energy collection capabilities.
Similar to solar panels on the ground, the process starts when the orbiting panel converts sunlight into electricity. What follows makes a difference. The system transforms that electricity into a laser or microwave beam rather than sending it through cables. This beam is sent down to a receiver station on Earth from space. The receiver transforms the beam back into electrical power that can be fed into the grid once it hits the ground.
The panel never has to worry about clouds or a lack of space on land because it is outside the atmosphere. Theoretically, it could provide energy to isolated islands, unreliable grids, or locations where constructing massive solar farms would be impossible.
From a single “super solar panel” to “powering regions”
Right now, the system under test is estimated to produce about 120 kW of power. Although it is not enough for running a city, it shows the concept can be implemented in practice. Space-based solar power that’s being used to power regions instead of neighborhoods doesn’t seem so impossible anymore, if a large number of these panels cooperated.
On Earth, solar farms are limited by weather, available land, and how close they are to power lines. Panels in space see sunlight almost all the time and can, in theory, send energy wherever the receiver is built. That could help places with weak grids or remote locations that currently depend on costly local generation. Countries like South Korea are planning space solar systems that could deliver tens or hundreds of gigawatts—enough to support a national grid.
A promising idea with big challenges to come
The road ahead is not going to be simple. It is expensive and hard to build and launch massive orbiting solar panel arrays. Engineers must create systems that endure extreme environments, avoid collisions with space debris, and develop or assemble in orbit. Furthermore, the safe and effective return of energy to Earth via laser or microwave power needs ground receivers that can cover an enormous area of many square kilometers and stay aligned.
When experts talk about “powering regions,” they are thinking on a gigantic scale, with gigawatt-class systems that dwarf today’s 120 kW experiments.
Nevertheless, it is a very innovative move to test a solar satellite in low Earth orbit. It’s an opportunity to test if in any weather or time of day, sunlight from space can be converted into useful power.