20 June 2010

Space-Based Solar Power: a solution to our burning need for energy

Posted by Ryan Anderson

People burn things. This crude way to get energy has done wonders for us as a species, but I think it’s about time we moved on.

It’s easy to forget how important burning stuff is in modern times because the burning is mostly hidden. Most of our electricity comes from burning coal and gas, but the furnaces are far away and instead of huddling around our campfire to cook and stay warm, we now huddle around the glow of computers and televisions. But somewhere, something is burning to make that possible.

If we want to go somewhere, we hop in a car and drive. Occasionally we have to fill the gas tank, but the explosions under the hood of the car are muffled and hidden, out of sight, out of mind. If we need to get somewhere far away quickly, we launch ourselves into the sky in airplanes, propelled by fuel burned at an incredible rate.

It’s easy to take for granted all the cheap energy that we get from burning things, but we have known for a long time that it is not an ideal solution. It’s dirty and inefficient and the looming threat of a fuel shortage is always present. All the easy sources of fuel have been tapped, so we turn to the difficult ones: shearing off the tops of mountains to get at their coal or pushing the limits of human technology to drill into oil reservoirs deep beneath the sea floor. Now, inevitably, something has gone wrong and the fuel that we prize so greatly is gushing from a wound in the earth and there is little we can do to stop it.

I’m reminded of the line from the Lord of the Rings, giving the reason for their downfall:

The dwarves delved too greedily and too deep. You know what they awoke in the darkness of Khazad-dum… shadow and flame.

The BP oil spill in the gulf forcibly reminds us of the price of our prosperity. The gusher will be capped eventually, and deep water drilling will resume eventually, but it’s clear that burning things for energy isn’t as easy as it used to be. Our demand for energy is exceeding our supply, and it is time to start developing alternatives.

Of all the alternative energy sources, solar and nuclear power are the most appealing to me. When you think about it, there are really only two sources of energy here on the Earth: radioactivity and solar. You may protest and say “what about wind, hydroelectric, geothermal?” But what drives the wind? The sun. What drives the water cycle? The sun. And what provides the earth’s internal heat? Radioactivity. And of course, all the energy that we have unleashed burning wood and coal and oil through the ages was originally solar energy as well.

Solar power has the potential to not only revolutionize our energy needs, but to stimulate space exploration. How, you ask? By putting the solar panels in space.

The idea of space-based solar power has been around for a long time, but we are just now getting close enough technologically for it to be feasible. Essentially, it works by launching huge solar arrays into space, where the sun is always shining and there is not an atmosphere to block the light. The arrays collect the sunlight and turn it directly into electricity, which powers microwave transmitters. These transmitters beam energy down to the Earth’s surface, where it is collected by antenna arrays and converted back into electricity. No need to mess around with giant steam turbines and dynamos anymore.

Initially, space-based solar power would be used in situations where there is no reliable power infrastructure: particularly military and disaster operations. As long as a receiving antenna can be deployed, energy can be beamed down to it from the panels in space. As the solar power technology improves, and launches become less expensive, and other sources of energy like coal and oil become more expensive, the demand for space-based solar power will increase.

The key turning point will be when space-based solar power becomes profitable. All of a sudden, it will no longer just be a neat technology used by advanced military forces, but a commercially viable technology with tons of room to grow. More demand for launches will drive the cost down, allowing other missions to be launched for much more reasonable prices. Astronauts will be trained to maintain and repair the solar arrays, and human spaceflight will become commonplace.

And of course, we will finally be able to move beyond the primitive practice of burning stuff to get our energy. Almost. Rockets still burn fuel to get into space. Some of them, such as the Falcon 9 even burn hydrocarbons: typically kerosene.  It seems fitting to me that rockets, the culmination of thousands of years of burning stuff, will finally free us from that necessity by providing nearly limitless, clean power.

I can’t wait.