...100 MW of Space Solar Power ...per single launch!
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From: Peter Fairbrother on 18 Dec 2009 07:35 Greg D. Moore (Strider) wrote: > "Sylvia Else" <sylvia(a)not.at.this.address> wrote in message > news:00185a93$0$2120$c3e8da3(a)news.astraweb.com... >> An obvious solution would be battery storage to balance supply against >> demand. Pity we don't have anything that approaches being usable that way. >> > > The one I'm hearing more and more about is compressed air. Not a panacea, > but apparently may be quite workable in many cases for peak power loads. There is also pumped storage, eg Ffestiniog in Wales. http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity -- Peter Fairbrother
From: Alain Fournier on 18 Dec 2009 09:59 Sylvia Else wrote: > That's fine if you have something to run them on, but they usually run > or oil or gas for sound economic reasons. Neither of those is an > unlimited resource. A few are hydro, but mostly not, and you can't just > build new hydrostations because you feel like it. You have to find a > suitable location. The easy (i.e. cheap) ones get done first - and > consequently have mostly been done already. > > An obvious solution would be battery storage to balance supply against > demand. Pity we don't have anything that approaches being usable that way. > > I suppose the power not needed to meed immediate demand could be used to > electrolyse water for use in our future hydrogen fuel cell cars (if > they're ever actually viable), though electroysis plant is expensive, > and the owners are likely to want to run it 24/7. Well 24/7 safe for two short periods in the year (twice 20 minutes if I recall correctly) is probably good enough. Same thing for aluminium smelters, they don't mind much shutting down twice a year for a short period if it is a planned shutdown. I suspect there are many other industries which would not mind much shutting down for two planned 20 minutes periods per year. As for power generation from other sources to meet demand in those short periods (demand which is low because in the middle of the night). Hydro electric can go a long way for that. About once a year they open the spigots of the Hoover dam just to rinse the river down stream. They could add power generators at the dam and generate lots of power in those 20 minutes, so instead of wasting energy to rinse the river, you meet energy demand to rinse the river. We do something like that here in Quebec, we generate just about all our energy from hydro and wind. When the wind falls at a peak in demand, we generate hydro at a rate which is not sustainable lowering the water level behind the dams. We can then replenish the water behind the dams when the wind picks up. Alain Fournier
From: Pat Flannery on 18 Dec 2009 13:45 David Spain wrote: > > Yes, GEO satellite do not actually remain fixed at a point, but do a little > figure 8 in the sky, unnoticable by the antennas that receive their signals. Since Earth's axial tilt is 23.44 degrees, if I'm figuring this right, that means the SPS will have go through a total of 46.88 degrees up and down movement in the sky daily to completely avoid its shadow (actually a little less as the shadow tapers as it gets further away from the Earth due to the fact that the sun isn't a point source of light, but has a visible angular size in the sky), however, I think this ends up with it getting into the Earth's shadow on a almost daily basis rather than just around the Spring and Fall equinoxes. Pat
From: Pat Flannery on 18 Dec 2009 14:07 Sylvia Else wrote: > > However, this highlights another issue, which affects the cost, and > that's that the generators cannot run at 100% capacity factor, because > the demand isn't always there. There has to be installed capacity to > meet the peaks in demand, not just the average. If he extra electrical power shows up, it will quickly get used somehow, then everyone will be counting on two SPS running at full power all the time...and will have to build a third one for when one of the other two goes into eclipse. ;-) One wild card in all this is if room temperature superconductors are ever made, as then you could build huge power grids spanning whole continents (or even the whole world) with superconducting transmission lines in it, and use those to make up any electrical shortfall while a individual power satellite is in eclipse. Pat
From: Pat Flannery on 18 Dec 2009 14:13
Sylvia Else wrote: > > An obvious solution would be battery storage to balance supply against > demand. Pity we don't have anything that approaches being usable that way. They were bouncing up and down a decade or so back about storing vast amounts of electricity in giant superconductor coils; what ever happened to that idea? Pat |