Obama Transition Team Examining Space Solar Power 275
DynaSoar writes "President-elect Obama's transition team has published for public comment a white paper entitled Space Solar Power (SSP) — A Solution for Energy Independence & Climate Change. The paper was prepared and submitted by the Space Frontier Foundation and other citizen space advocates, and calls for the new Administration to make development of Space Solar Power a national priority. The SSP white paper was among the first ten released by the Obama transition team. It is the first and only space-related white paper released by the team to date. With 145 comments thus far, it is already among the top five most-discussed of the 20-some white papers on Change.gov."
Re:How? (Score:3, Interesting)
Well stuff has been put up in space before. No biggie. What I'm wondering is how they plan to get the energy back down here.
Any one have links to actual engineering proposals of how Space Solar Power would work and its benefits? Seems to me like "space" is not one of them, there is plenty of desert and whatnot to put solar cells in here on earth with much less maintenance cost and of course the possibility of running wires to get the energy to wherever it is actually needed.
From The Economist (Score:5, Interesting)
Recent space solar power article from The Economist
http://www.economist.com/science/tq/displaystory.cfm?story_id=12673299 [economist.com]
Re:Why bother with space solar power? (Score:2, Interesting)
Though this is more about pie-in-the-sky this would be cool and inspiring stuff, practically, our best options right now are solar thermal power.
Concentrated solar power uses no new materials-- glass, steel, mirrors, steam turbines, water, and occasionally fancy salts that we've already invented. It's one of the only renewable alternatives that doesn't want any money for research, just help getting some of the start up money to use materials we already have and make here in the US to build up these plants. Though they're not price-competitive yet, most research suggests that once enough capacity is built, economy of scale will kick in and it'll be competitive with fossil fuel costs within five years.
Talk about the ability to prime pump a market.
Plus, concentrated solar works naturally with usage peaks and can be used for desalinization/purification of water which is great considering regions where there is little rain/cloud coverage is ideal.
Two things need to happen-- we need to build more terrestrial solar capacity, both concentrated thermal and photovoltaic, and more importantly, we need to construct better power infrastructure so we can deliver energy from high solar density areas (which are typically desolate and therefore don't have the power pumping capacity some areas have) across far distances.
Re:How? (Score:1, Interesting)
Wrong, a return trip to the moon would be the first step toward the harvest of easily fusible hydrogen and helium-3. Want energy independence? Get fusion working.
Re:Numbers? (Score:5, Interesting)
I read the Economist article and noted the name of the scientist ("Mankins") who researched it.
I typed "mankins microwave transmission efficiency loss" into Google and the second link was an IEEE article with the abstract appended below.
Your number is 45% for DC-to-
DC.
So not assuming that solar-cell efficiency can make it to 50%, but cheerfully assuming that the kind of cells that will do well in an industrial setting space for long periods can reach today's in-the-lab max of 40%, your area comes to:
560 km^2 / 40% / 45% = 3111 km^2.
And so what? There's a lot more space than that out there. (See opening paras of Hitchhiker's Guide for how much.) The question is the available money, not the available space. Those 556GW of nuclear had a total capital cost of well over a trillion. (And a land area sucked up of well over 3111 km^2 by the way, add up all the mines and waste dumps and reprocessing facilities, not just the plants. And that's area we can use for other things, down here; not a lot of other things to do with 3111 km^2 of orbit.)
The Economist article is unequivocal: SSP would cost FIFTY CENTS per kWh. That's just awful, way worse than earth-based solar or wind, even backed up with 85 watts per 100W so that they are base-load capable.
But one lives, and allocates research dollars, in hope. I'd bump the fusion budget from $300M to $500M, and match that with SSP research funds...about $400M of which would go to "cheaper lift costs", the truly key barrier.
Space solar power programs and microwave wireless power transmission technology
McSpadden, J.O.; Mankins, J.C.
Microwave Magazine, IEEE
Volume 3, Issue 4, Dec 2002 Page(s): 46 - 57
Digital Object Identifier 10.1109/MMW.2002.1145675
Summary: Future large-scale space solar power (SSP) will form a very complex integrated system of systems requiring numerous significant advances in current technology and capabilities. Ongoing technology developments have narrowed many of the gaps, but major technical, regulatory, and conceptual hurdles remain. Continuing systems concept studies and analyses will be critical to success, as will following a clear strategic R&T road map. This road map must assure both an incremental and evolutionary approach to developing needed technologies and systems is followed, with significant and broadly applicable advances with each increment. In particular, the technologies and systems needed for SPS must support highly leveraged applicability to needs in space science, robotic and human exploration, and the development of space. Considerable progress has been made in the critical area of microwave power transmission. At 5.8 GHz, DC-RF converters with efficiencies over 80% are achievable today. Rectennas developed at 5.8 GHz have also been measured with efficiencies greater than 80%. With optimized components in both the transmitter and rectenna, an SPS system has the potential of a DC-to-DC efficiency of 45%.
Re:Why bother with space solar power? (Score:4, Interesting)
Why? Lots of reasons, the most important being:
A. Cost of putting such a LARGE array up there.
B. Inefficiencies in power transmission (how're you going to beam it to the surface? Microwaves? Why not just harness it at ground level and store it in batteries, and cut out several points where conversion losses would be found?)
C. Maintenance costs/damage protection/prevention - just how do you plan on keeping these things safe from random space debris flying at ultrasonic speeds?
D. energy costs to build/deploy - these things would have to be MASSIVE with current solar technologies to get usable power after factoring in loss for transmission and conversion.
Need more?
Re:Who needs exploration, anyway? (Score:4, Interesting)
Exactly, what really needs to be known is if their is water on the moon, and how much, first. That can be done through probes a lot cheaper.
If there is an ocean at the pole than sending people up at a later date would make sense because you could then extract essentials in-sutro, saving lots on resupply missions, and with the low gravity potentially allowing longer stays than Micro G saving cost on replacing crew. Which could then possibly assemble more probes on the moon cheaper then pushing them up the gravity well or even catch a NEO. Why we haven't figured out the most important part of future space travel (what resource's are easy and cheap to get off the moon) through cheap probes yet I can't figure out.
Re:Numbers? (Score:3, Interesting)
What about space junk? (Score:2, Interesting)
Re:Who do you trust with a death ray? (Score:3, Interesting)
That's a poor analogy.
You're putting all the light at a focal point. This would be the equivalent of having the lens too close to the ant, with it out of focus... the ant will just be rather bright.
What I'm saying with the microwave beam is that you can't focus it that finely. Instead the system would be transmitting from many point sources, and the beam just can't be that easily focused without having a huuuuuge dish.
One of the earlier proposals from the JPL was to use a phase-injected array of magnetrons to provide a steered microwave beam. That beam will still be really, really wide ... remember the wavelength of EM energy we're dealing with is on the order of centimeters in length ... the EM energy going through your magnifying glass is nanometers in length. You can easily focus that energy with a 1" magnifying glass... when it comes to microwaves, especially from GEO, it's just not going to be that focused. Even if you scale this up to multi-gigawatts ... let's say 1000 GW - the entire US demand for electricity at the end of 2007. If that power was beamed down from the sky at 100% efficiency, over an area of land of 100km x 100km, that's only 100 W/m2 ... now if we reduce that down to an area like 20km x 20km, it's 2.5 kW/m2 - that's probably not safe.
But at 100 W/m2 it should be okay ... obviously there's no single 100 km x 100 km site that's practical, so you have different sites around the country... makes sense anyhow - you don't want all the power in one spot anyhow.
Every single paper explaining this project basically cites the beam as being highly divergent and requiring - a very large field - to harvest the power.
An anonymous poster further up however provides the best response about risks -
- the amount of rocket launches required to implement a system on the scale we'd want would basically destroy the ozone layer.
That's not acceptable by any means ... that risks killing off large portions of the biosphere. Most photosynthetic plants really don't like UV light in any higher dose than necessary. It's one thing to zap them with a single short pulse, it's another thing to provide continous wave ionization of the epidermis...
The military application has always been the ability to have a power source anywhere the forces go in the world.
Death beam from above isn't practical using this system, they'd more likely use orbital death rods, fission reaction powered gamma/x-ray beam, or good ole missiles.
I vote the idea down simply for the damage we'll do launching that many rockets into space.
CEO Comsat interference? (Score:1, Interesting)
Would a space solar satellite cause unacceptable interference with GEO communication satellites? They are only 100 watts or so, a GW beam nearby might really cause some problems on dish sidelobes.
Re:Space Solar Power does make sense, sometimes (Score:3, Interesting)
You still have to transmit the power to the Earth... and surprisingly water vapor also absorbs a great amount of the energy. A cloudy day on the Earth is therefore going to reduce the amount of power available from these satellites. So yeah, weather has an impact here.
BTW, if you thought global warming due to CO2 production was huge, just wait until you get the figures for what happens to that other 80%+ of the energy that doesn't get collected on the surface. It all gets absorbed directly into the Earth's atmosphere. Talk about anthroprgenic climate change. Has this really been thought through here?