Announcing: Space Windmills

An out-of-the-box, out-of-this-world energy solution

Windmills in space? (by the author using DistroPic)

Space windmills! I hear you laughing. Impossible! Doesn’t this idiot know that there is no air in space, and therefore no wind?

Ha! You couldn’t be more wrong.

Lookee here: LightSail 2 just demonstrated the feasibility of powering spacecraft with sails—solar sails. Because space has wind—the solar winds.

If the solar winds can be harnessed to power a spaceship, then surely they can be harnessed to power a solar windmill.

“Why would we want to build space windmills?” you ask. For the same reason that we want to build solar photovoltaic (PV) and possibly solar thermal electrical generators in space: To generate a steady supply of electricity that can be beamed via microwaves to anywhere on earth.

Solar windmills can supply the same 24/7 power as solar PV, but at much lower costs.

The cost of PV panel manufacture is very much a big issue for both earthbound and space applications, when deployed at scale. PV cells currently require particular metals that must be mined, a brutal and dirty process. And besides, they are in short supply so we can expect their prices to be going up.

This is not what space windmills will look like (by the author using DistroPic)

Solar sails required only huge sheets of mylar and some thin structural framework. All the materials needed can probably be sourced from the moon at very low launch costs.

Space windmills also avoid most of the problems with earthbound windmills. The monster blades used by terrestrial windmills consume a lot of resources. They are expensive to transport and install. Disposal as they reach end of life is an issue. And a significant amount of CO2 is emitted to the atmosphere during their construction.

Solar windmill blades, on the other hand, have low materials cost as mentioned previously.

Evolving modular space construction methods will make them relatively cheap to transport and install.

They are easily disposed of by de-orbiting them and letting them burn up in the atmosphere, like Lightsail 2’s fate.

Zero CO2 will be added to the earth’s atmosphere if the materials are sourced on the moon and construction is done entirely in space. Well, I guess some CO2 will be generated by launches of support missions from earth. But that will be minimal compared to the value of the power that a solar windmill will generate over its life, which should be very long in space.

I can foresee beautiful gardens of solar windmills unfurling like so many humongous silver flowers rotating majestically in the solar winds. If we build enough of them, they may even act as a solar sunshade, reducing global warming. In the event of a major solar flare, we could cluster all of the windmills into the path of the flare, preventing another Carrington event from frying electronics across the globe.

Solar windmills flowering in space (by the author using DistroPic)

So there it is. Solar windmills, an out-of-this-world long-term solution for providing the electricity that powers our civilization. I just invented it, and I give the idea as a gift to the world. I leave the details as an exercise for the scientists and engineers to work out.

— Lannie Rose, December 2022
preferred pronouns: she/her/hers