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One of the great things about conventional solar technology is that it is completely scalable, it is fesable and practical for a family to purchase and install a solar power system on their own home, regardless of population density or otherwise, wheras these large dishes on sun-tracking mounts need a lot of space, plus constant maintenance to keep the moving parts and tracking system working.People have built mammoth scale sun-tracking reflecting systems to concentrate heat and generate power before, but they have generally fallen into disrepair after several years.

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"where does it get the power to compress the hydrogen?" I was thinking the same thing...Seems like the power to compress the hydrogen wil offset any power gained from its rapid expansion. Also, the (solar) heat absorbed during this rapid expansion will be recovered as thermal pollution, when the hydrogen is re-compressed. But I suppose that if some mecanical energy is removed from the system, as the working load, then some of the energy of expansion must have gone into that, as it had to come from somewhere. So perhaps this is a viable way to convert solar energy into usable energy.I would expect that just about any gas can be used, and hydrogen is not specifically needed. it just as to be something compresible, and that will rapidly expand when heated.I guess I'll go RTFA now! :-)

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Actually you put the mirror in polar orbit and focus it down on something. Course you'd probably burn a hole through the atmosphere while you're at it.

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Why? probably because one little dust strike on the space-based beam relay, and you knock it out of alignment, sweeping across the planet with mega watts of microwave energy. That, and the fact that it would be insanely expensive to launch, maintain, and convert the energy 'beam' back to electricity on earth. Its not like we don't have the empty space to put solar farms here on the planet, putting them in space serves no purpose. We are not starved for sun, yet. Yes, the space collectors would be much more effective, but the transmission to earth is the weak link, subject to loss and distortion from the atmosphere.

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@ToddMLmy bad... typing too fast, extra 0 in the 100mi sides of the square. What I meant was10mi x 10mi = 100 sq. milesWhat you say is true: Surface Area of a rectangle (for a square L = H) = Length x Height100mi * 100mi = 10000 sq. milesMeaning the area can be covered with 10000 squares, with sides equaling 1mi each.That statement you mentioned was very ambigous and poorly written, my wife who's a B.A. in English and a speech writer said that statement is poorly written. She would say it's 10mi x 10mi = 100 sq. miles - she warned me not to draw any conclusions from it because it was so ambigous. So, let's take what they say in the B.W. article to see if we can figure what they mean by miles square verbiage."Consumers, of course, are unlikely to plant Stirling Energy's huge 37-foot dishes in their backyards, even if they are the most efficient solar generators around. ... Osborn says that a dish farm of 11 miles square could produce as much electricity as the 2,050 MW from Hoover Dam. "We're already looking at a half-dozen one-square-mile sites in the California desert," he says, "and there's lots and lots more territory there."If we take the footprint of the device to be 38ft + 12ft (add 12 ft to one height, and one width, my estimation for maintenance truck and crew to work on the things!)50ft x 50ft = 2500sq ft, the size of house! (from the article: "Measuring 38 feet across and costing $250,000, this is no residential add-on. It’s meant for the opposite end of the power chain—" the business week article just says 37 ft dish... what? across? height? 37ft what?)And each unit capable of producing 25kW of power...How many dishes would be needed for 2,050MW? 2050MW = 2,050,000kW (Kw = 2050MW * (1000kW / 1MW))X units = 2,050,000kW * (1unit / 25kw) = 82,000 units or these devices.82,000units * 2500sq ft = 205,000,000unit sq ftsq mi = 205,000,000sq ft * (1sq mi / 27,878,400sq ft) = 7.35sq miwhich is pretty close to the 11sq mi in the B.W. article. While I could still contact the source for clarification, I think the math here shows that when they used the verbiage "miles square", they meant square miles meaning 10mi x 10mi = 100sq mi. Considering that the state of CA, is 158,402sq miles the 10,000sq mi you mention is roughly 1/10 the area of CA! the Mojave Desert is 22,000sq mi. The area you mention would take up half the Mojave. I doubt that would fly.I estimated the area footprint of the units to be 50sq ft by allowing a 12ft space on one width and one height side (or a 6ft margin around the devices). Let's do the math:We know it takes 82,000 units of the current 25kW / unit to generate the 2,050MW they mention in the B.W. article and they say it covers an area 11sq mi...sq ft = 11sq mi * (27,878,400sq ft / 1sq mi) = 306,662,400sq ftsq ft/unit = 306,662,400sq ft / 82,000units = 3,739.79 sq ft/unitTake the square root: 61.15 per side61.15ft - 38ft = 23.15ft is what they must have in mind for the spacing between each unit or about 12ft margin around each unit. I had added the 12 ft to only one of each side, which seems based on the statements in B.W. each side of the device will have a 12ft margin added to it for maintenance instead of the 6ft margin I estimated (I was thinking they'd want to save on sq mileage as much as possible so I estimated very conservatively thinking they'd try to sqeeze a mid size truck - they must have some bigger equipement in mind...)

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@konspence and ToddMLSorry ToddML, I should thank konspence for catching my mistake, but the previous comment I made was to clear up the ambigous statement by the B.W. article you mentioned which seems to have led you to believe their use of the verbiage "miles square" meant 10000sq mi instead of 100sq mi.I should have paid closer attention to who wrote the comment.... my appologies for the mistake.

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