WPenner's Blog

I was first exposed to the idea of space-based power in George Friedman's 2010 book The Next 100 Years.¹ The idea is fairly simple, locate solar panels above weather and Earth-based obstructions and at a point where the sun shines continuously. Geo-synchronous (GEO) orbits achieve the correct positioning. This positioning overcomes some of solar's fundamental problems: not generating energy at night and reduced power when clouds, dust, trees, or buildings block the sun.

Friedman argued that the US military would develop the technology to keep America at the forefront of energy abundance in the coming decades. That prediction seemed a safe bet, because India, Japan and the US were leading researchers then. Since that writing, the US found (then gave up on) fracking, research has dwindled to a trickle, and it is the EU that is continues to consider a future implementation.

Cost/Benefit Analysis

The EU, having run 2 independent analyzes of the technology, concluded that the short-term prospects do not look good. There are still more expenses than benefits.

Space-based solar power's biggest cost hurdle is getting the equipment into space. The EU estimates a solar powered satellite in geosynchronous orbit might be a kilometre across. Compared to the ISS, which took dozens of launches to LEO, a power station weighing thousands of tonnes could require an order of magnitude more launches.² Depending on the technology used to transmit power, the ground receiving station may require ten times more space.

Read about why energy density is so important in space in Energy in Space

Advances in solar panel materials do not change the size of the station or how many launches they need to lift all the equipment into orbit. What may change is the operational efficiency of the installation.

This is because another challenge to solar power technology is the damage radiation causes silicon panels outside of Earth's atmosphere.

New Panel Technology

Solestial is an Arizona State University spin-off startup that aims to improve space solar cells. Applying learning from Earth-based cells to improve efficiency and new materials, they expect to deliver a better panel. Their modified silicon material gets pressed 20 microns thick, compared to ~160 microns for commercial cells on earth. The material naturally curls, which allows it to anneal away damage from radiation when heated by the sun. The result is a panel rated 20% efficient with a 10-year lifespan.³

The ESA's announcement of project SOLARIS, talks about setting the groundwork for a decision in 2025 to develop the vision necessary to create the equipment for space-based solar power. ⁴ In other words, it is an announcement of little more than an intention to think about the topic later. Such foot-dragging and analysis paralysis is a common complaint about EU bureaucracy. While the initial impetus for the project came from global warming, a more pressing concern in 2022 is the loss of access to Russian energy combined with continued social stigmatization of nuclear.⁵

Read about space-based power possibilities beyond beaming energy back to earth in Getting Around in Space