SBSP–Solar power from space

Denis Pombriant

There’s a good deal of concern in some circles about ever converting the economy to 100 percent carbon free energy and that’s reasonable. There will be applications that specifically require fossil fuels well into the future like commercial aviation and war fighting, though we’d be smart to eliminate war. Although electric aircraft engines are on the drawing boards and have been tested, they are limited to propeller designs which means slower and lower flying. Nonetheless, there is a reasonable expectation that we could see commercial aircraft ferrying people up to 1,000 miles by the middle of the next decade.

Boeing air taxi, still using propellers.

The problem with electric aircraft is still batteries. According to the above referenced article “At present, 1000 pounds of jet fuel gives you about 14 times more power than 1000 pounds of batteries.” And unstated, as fuel is used, it relieves the aircraft of the weight it must carry, batteries hang around.

That said, it’s likely that we’ll be emitting CO2 well into the future–as long as the fossil fuels last that is. But that doesn’t mean we can’t get to carbon neutral or even carbon negative where we actually remove some carbon from the air over time. That’s one side of the coin, the other is how we’ll generate the necessary electricity to power our world without fossil fuels.

Some of the solutions we’ve examined so far include hydropower, wind, solar, and geothermal. We haven’t looked into tidal energy sources for practicality reasons and nuclear has so many problems that make it unwise to use and non-essential given other options that we’ll just skip over it. We have given no attention whatsoever to space-based solar panels (SBSP) and that’s too bad because the idea has legs.

Power from space

SBSP is not the first option on anyone’s list of power alternatives, but it provides a tantalizing insight into just how much energy is available to us, with a little engineering, that it should help allay fears about the next supply of energy.

Conceptual drawing of SBSP.

Very briefly, SBSP is what it sounds like. Parking solar farms in geostationary orbit and beaming the resulting power down to earth via low density microwaves. Let’s unpack this.

1. First, the orbit in question is geostationary meaning the object in orbit appears to hover at 22,235 miles or 35,786 kilometers above the equator making the object look as if it is not moving.

2. Next, the solar panels collect some of the 200 million GW of energy coming at them converting it to low density microwaves and sending a constant microwave beam to the ground. This would eliminate any issues of inconstancy seen in solar and wind.

3. A rectenna, which could be as much as 2 miles wide, on the ground collects the stream, converts it to electricity and pushes it out through a grid. At off peak hours for one location, the solar farm could beam its power to other satellites for downloading to the parts of the planet then experiencing peak demand.

This may seem like science fiction, but the reality is, there’s already a fleet of solar-powered communication satellites is already in orbit and beaming down other electromagnetic frequenciesin the form of TV signals and cell-phone calls. Why not electricity too? There’s no good reason why not, other than demand and cost.

Demand might not be there yet but if or when it arrives, the physics and economics are nearly complete. We have the space lift capacity, for instance SpaceX’s Falcon Heavy rocket already lifts such payloads for commercial customers. Also, in the vacuum of space solar panels operate five to ten times more effectively than in the atmosphere.

More good news, the sun never sets up there so it’s reasonable to expect close to 100 percent up time for solar farms augmented by redundancy. Moreover, SBSP might be a boon to the emerging world because it could eliminate a need for developing massive electric power infrastructure. Cellphones made telecommunication easy in lands that didn’t have much of a conventional telephone infrastructure and much the same could happen for electric power consumption. Also, emerging nations could forego the costs of building expensive generating infrastructure or purchasing dirty fuels simply by making a single monthly payment to an international power company.

Collecting devices don’t have to be flat.

Final thoughts

SBSP amounts to placing a powergrid in the skybut there are more terrestrial political issues with such a move than technical ones. SBSP would offer up an opportunity to greatly expand international space programs as some permanent complement of local engineers might be needed for maintenance. But these farms would also be an inviting target for warfare. There’s no easier way to disable a rival than by messing with its power grid. So, we’d need some diplomacy and likely a treaty on the order of the Law of the Sea or the Geneva Conventions to ensure peaceful use and deter abuse.

Next, we’d likely need some new international governance protocols for any international corporation wanting to sell its power to the highest bidder. At that point, and once billions of people in emerging countries become dependent on power from space, that power could be seen as a basic human right. Multiple responsibilities for vendors and consumers come with such a step.

Artist’s rendering of space elevator.

Lastly, SBSP won’t happen tomorrow but it’s a logical outgrowth of new thinking about power generation and consumption made necessary by climate change and decline of fossil fuels. It will also be a likely driver for a return to space exploration. For instance, a space elevatorcould become practical with SBSP. A space elevator is basically a long cable anchored at the equator and held in place by a counter weight above the minimum altitude for geostationary orbit. With the cable in place you’d need a mechanical device to climb it, but you’d eliminate the need for rockets. The device could easily be powered by solar power from space and, as a matter of fact, the solar farm could form at least part of the counterweight needed to keep the cable up.

The current climate challenge is quite serious, but it should be seen, at least in part, as a big opportunity for the human race to advance in numerous directions.

Denis Pombriant

Written by

Researcher, author of multiple books including “The Age of Sustainability” about solutions for climate change. Technology, business, economics.

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