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.
Power from space does sound extremely attractive, suggesting the possibility of energy at very low cost to the environment. It may be possible, in time, to manufacture solar arrays off earth removing even this environmental cost. However I feel we need to be very careful. The possibility of using space based energy collection is so seductive that we will become even more energy greedy, requiring greater and greater supplies of this “clean” energy that the total input will eventually become noticeable in comparison to the solar irradiance onto the Earth’s surface. We will then have an even more dramatic threat to the stability of our climate. (I am not familiar enough with climate analysis to know what effect there would be to say a 1% increase in total energy input but I believe that it is fairly clear that even small changes can have dramatic effects.)
In my view we need to develop space based power collection and space based manufacturing capability at the same time. In this way it may be possible to make use of some space based power on the Earth’s surface without any significant additional energy input into the Earth’s ecosystem.
I don’t think that will be a problem for a *VERY* long time. The earth already receives an almost absurdly large amount of energy from the sun. For space solar power to contribute even 1% more would require phenomenally large and numerous solar power satellites.
…and all those solar arrays would have to be occult the Sun from the Earth, at least part of the time. The first solar power arrays would likely be in geostationary orbit, so that they can hover over the receiving station on the ground. Those would only occult (a fraction of) the Sun for a very small percentage of each orbit.
However, even this has a conceptually simple solution. For space-based solar power to be effective, we will need to be able to transmit power for hundreds to thousands of kilometers. So, the actual solar collector arrays could be located in sun-synchronous orbits, Lagrange points, or even polar halo orbits near the Earth if the solar arrays are large enough to act as solar sails. The collectors could then beam their power over to a geostationary relay satellite. The impact on solar irradiance would be negligible.
And here’s another interesting idea, if ISRU gets cranking: http://www.shimz.co.jp/english/theme/dream/lunaring.html (be sure to check out the other items on the left menu of that page for some more great concept art!)
Right now, the concept of space-based solar power is starting to catch on within the aerospace community. I think there are three major research hurdles before it’ll happen:
– We have to figure out how to transmit power effectively from the solar power stations to Earth. I think the major problem there is in keeping the beam spot size small enough to build a reasonably-sized receiving station, since any beam will spread over the course of its path. I think the Air Force’s airborne laser would be a good starting point – they use that to shoot down missiles, which means it has to pinpoint a very small target, and it’s been tested over hundreds of kilometers in the atmosphere!
– We have to figure out how to efficiently deploy really large, floppy structures in space. This has been an active research topic for a very long time, and there are a lot of potential solutions. However, the materials science, control algorithms, and mechanism design will have to do a little catching up before we can implement that on arrays on the scale of square kilometers.
– An alternative to the large deployment is that we could figure out how to build the arrays in place. If we could capture a nickel-iron asteroid in GEO orbit (hey, look! another reason to support Obama’s NASA vision!) then it’s not unreasonable to think that we could “extrude” a large structure from the asteroid, maybe using specialty materials brought up from Earth to manufacture the solar cells themselves. I think that is by far the most exciting possibility, since if we could build solar power stations out of asteroids, we could build lots of other things, too…
Politicians and activists sometimes talk about a “Manhattan Project for climate change.” Space-based solar power might fit the bill with its technical challenge, lofty aspirations, and potential impact, don’t you think?
Check out David R. Criswell’s Lunar Solar Power plans. Solar Power Sats make space junk!
This energy can also be obtained by the semi-conductor and is used to generate electricity. It is a simple process of collecting solar energy using solar energy panels for use in your home. The panels are typically made from wood or metal box, black box to the right size to fit on the roof of the house where it is installed. A well-insulated box painted black inside to make the sun’s energy to focus more intensely and to increase the amount of energy absorbed.
Of course, solar energy can be collected on the ground too, but for large-scale energy production, it would require huge amounts of land to be cleared. If all houses had solar panels, that would help, but you still suffer from clouds and night and atmospheric attenuation.
Also, why does painting the box black help? I didn’t think that solar panels could convert infrared light into electricity.
Typically, wind energy systems for homes include high-end point with five rotating blades against the wind. To what extent the wind towers should be in your home depends on factors such as relative wind speed in your area, a high tower to lower the wind speed and the area where the tower is shorter for more wind zones speed
An excellent article and I’ve always been for nuclear power.
[…] Space-Based Solar Power: a solution to our burning need for energy … […]
Keep on posting such stories. I like to read stories like this. By the way add some pics 🙂
The primary concern regarding power-beaming concentrated microwaves from a space solar power satellite are the biohazards accompanying high-intensity microwaves, as explained in the book Sunstroke by David Kagan.
I read Sunstroke and was impressed that David Kagan predicted that a space-based solar power station would be built and deployed by not only the US, but also by other nations, under the pretense of being a “purely alternative energy source to supply unlimited power to major cities”. Kagan spells out quite clearly that such space solar power stations employing high-intensity microwave beams could also be used as a devastating multi-pronged weapon: it can supply electricity to the military, be used to fry enemy ground troops, aircraft, ocean-going vessels, and also be used to disrupt enemy communications as well as destroy their agricultural capabilities. And the US EPA agrees.
As I understand it, the beams would not be high-intensity, just high power. The intensities that are talked about for proposed systems are within safe levels even for prolonged exposure: http://en.wikipedia.org/wiki/Space-based_solar_power#Counter_arguments
Of course, that doesn’t stop a nefarious person or agency from focusing them more than necessary for power transmission…
Hey there just wanted to give you a quick heads up and let you know a few of the images aren’t loading properly. I’m not sure why but I think its a linking
issue. I’ve tried it in two different web browsers and both show the same outcome.