Posted on 11/10/2007 3:48:05 AM PST by shove_it
They're officially all the rage in the Pentagon and the private space industry: orbiting satellites that send solar power back down to earth to fight global warming—and turn a profit.
Space-based solar power may become an important energy source as fossil-fuel supplies dwindle in midcentury: A single 1-kilometer-wide solar array could collect enough power in a year to rival the entire world’s oil reserves.
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A Pentagon report released in October could mean the stars are finally aligning for space-based solar power, or SBSP. According to the report, SBSP is becoming more feasible, and eventually could help head off crises such as climate change and wars over diminishing energy supplies. “The challenge is one of perception,” says John Mankins, president of the Space Power Association and the leader of NASA’s mid-1990s SBSP study. “There are people in senior leadership positions who believe everything in space has to cost trillions.”
The new report imagines a market-based approach. Eventually, SBSP may become enormously profitable—and the Pentagon hopes it will lure the growing private space industry. The government would fund launches to place initial arrays in orbit by 2016, with private firms taking over operations from there. This plan could limit government costs to about $10 billion.
As envisioned, massive orbiting solar arrays, situated to remain in sunlight nearly continuously, will beam multiple megawatts of energy to Earth via microwave beams. The energy will be transmitted to mesh receivers placed over open farmland and in strategic remote locations, then fed into the nation’s electrical grid. The goal: To provide 10 percent of the United States’ base-load power supply by 2050.
Ultimately, the report estimates, a single kilometer-wide array could collect enough power in one year to rival the energy locked in the world’s oil reserves.
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(Excerpt) Read more at popularmechanics.com ...
I had to check the numbers myself. Instead I just used 20 million barrels per day of oil to see how well it would do to replace US energy usage. The energy stored in the oil used in one day is 1.22 * 10^17 J. The energy incident on a square array (in a place where it won’t be eclipsed by the Earth often such as a geostationary orbit) is 1.17 * 10^14 J.
To be fair, the article only said a single kilometer-wide array. It *could* be 1000 km long! I also didn’t take into account the efficiencies of transmission or thermodynamics. I’m just drawing a rough conclusion to within an order of magnitude.
Of course when you look at worldwide energy usage of 15 TW, this idea is laughable. Overall 1.3 * 10^18 J are used per day. So now we have a 100 km by 100 km array (or perhaps 1 km by 10,000 km to meet this article’s requirements).
I look at oil as sort of like earth's batteries, where it's stored the accumulated energy of millions of years of sunshine (if you believe the dead dinosaur theory of oil). Since you are clearly versed in this subject, my question is what happens if we actually do use up all the oil? Is it even possible to produce the energy the world requires even at current levels (disallowing for growth) without oil, from ANY source? I would guess nuclear power would work, but it's not portable / storable like petroleum energy is.
Turbo diesels are SWEET, no doubt! My bro-in-law has one, gets 19 mpg with club cab, 4wd and a camper top on the back (I know, it doesn't have much drag, but it is extra weight), and that thing's got some KICK to it when he stomps it.
I see the energy generated in space as being used in space. Putting entire Chinese factories in orbit and wafting down palletloads of high value manufactured goods would be more cost-effective than trying to ship energy to a fearful Earth.
One major efficiency in solar collection is the amount of heat loss in solar energy absorbed by the atmosphere. Politically, the idea might be also advanced by reducing the dreaded ‘global warming’.
On the other hand, getting that power back to earth is another issue. In the late 70s we had looked at microwaving it back to large collector arrays in the ocean. Of course it might not be so good for birds flying in the area, planes or submarines.
It would have to be close to 187,000 km long to reach the available power of their claim. Although I suspect there are some significant difficulties keeping an object in orbit that is 15 times larger than the diameter of the earth.
Leave it to the global warming nuts to propose a solution that involves beaming massive amounts of microwave energy through moisture laden atmosphere.
I forgot to mention, one impediment to space based solar arrays was the lack of atmosphere on photoelectric materials. The partial pressure for many of those materials would result in their outgassing over time, especially as they heated up during the photoelectric process. I don’t know the state of the art, but that was a purely intellectual exercise back then.
Exactly. As with resources mined in space.
The tragic thing is that the money we could have spent developing space industry and opening that frontier was instead spent financing entitlements. We probably dumped 100 to 1000 times as much as would have been needed to get space industry going into that rathole and have nothing to show for it but negative social indicators and a "need" to dump more down it.
It is hard to say what might have come from investing in space, but it probably would have bigger impact than information technology, potentially as much as the industrial revolution.
Uranium in fission reactions is limited as well. Methane Hydrates is a enormous deposit of resources, containing several times more Btus than all other fossil fuels combined. But after a several centuries it would be used up. Of course trying to predict energy usage centuries away is rather foolish. Try to use 1900 as basis and predict the energy needs of today. I suspect Fusion reactions will become more import in the far future, or more likely, a technology we are not aware of today.
Well thats the problem isn't it. Nuclear power isn't the solution to the oil problem because it isn't competing with oil. Nuclear power is competing with coal which is already much cheaper than oil. It is a real pain to be able to take energy that is so easy to move around on the electrical grid and put it into an automobile. If it was easy, we'd have electrically powered cars running from coal electrical power plants.
Hydrogen, batteries, and fuel cells need a little discussing here. Hydrogen isn't used in pure form because unless you use cryogenics or very high pressure fuel tanks the energy density will be much too low for long trips. Neither of those options is going to sell very well. Batteries are only now approaching the point where they may be feasibly used for short trips in a city (ideas like the plug-in Prius modifications are brilliant). So this is certainly an advance, but it doesn't help for longer trips (i.e. trucks). And fuel cells require either high temperature fuel cells that take hours to warm up or low temperature fuel cells with expensive catalysts. And even those fuel cells will need to get their hydrogen from reforming a hydrocarbon to achieve a decent range (i.e. a gas tank).
So in the short term we are stuck with oil. It is my hope that ultracapacitor and battery advances in the future may make it possible to cut out hydrocarbons from trips of less than 50 miles or so. And hopefully fuel cells will become economical. They will be extremely beneficial because they operate with much higher efficiencies than other hydrocarbon engines.
Exactly. One of the things I learned when briefly studying geophysics is that when most people talk about reserves, they are only talking about the reserves that are economically mineable today. I almost want to smack people due to their stupidity when claiming that our uranium deposits are going to run out in 100 years. It is a big planet and it has barely been explored at all for uranium (in contrast with oil).
Keep in mind, the same applies for oil. Recoverable reserves from known fields at $30 a barrel and $100 a barrel are drastically different numbers.
I agree and I always do keep that in mind. In fact these levels are going to make a lot of recoverable reserves of some previously unrecoverable hydrocarbons like oil shale.
check out www.spacedev.com .... small, publicly traded company that could very well be a player here.
International Energy Outlook 2007
Chapter 3 - Petroleum and Other Liquids Fuels
http://www.eia.doe.gov/oiaf/ieo/oil.html
Energy Information Administration, statistical agency of the U.S. Department of Energy
You may want to check out this stock traded on the Toronto exchange: WPT.TO. Also, CLNE to go along with it. These are energy solutions more down to earth.
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