> And where, pray tell, are they getting the water to clean all those mirro= rs? Ah. Uncloaking :-). They cover the water budget on their site. As noted, it is well below the requirements for eg dish concentrator. As I noted > water use for dish Stirling is low - used only for mirror cleaning > - all air cooling is used. All power plants use some water. Nuclear water use unknown to me. I'm "reliably informed" that in an open market, without government guaranteed protection against liability as they have at present, nuclear plants of any sort are a non starter. Plus, regardless of the merits of nuclear contamination when used properly, it is unlikely [tm] that people would want to break into a dish-Stirling site and carry off bits of the plant to commit acts of terrorism with. Unlike 'some other' technologies :-(. This may not be "fair" when comparing systems costs - but it's entirely realistic, alas. > Is the labor free? Maybe the desert animals will brush the mirrors off wi= th > their tails, or the winds of dust storms will clear some of the old dust = off > increasing output just like it does for the mars rovers. As above. Water use is included in their figurings. > What about maintenance of the engines themselves? Do you seriously believ= e a > mechanical device (of any kind) is going to keep operating for 20 years s= o > you can break even? No. I offered a few simplistic calculations about what the necessary costings looked like and specifically noted what I hadn't included. I offered very very very rough projections at 5/10/20 year lifetimes. Note that at 10% IRR the 20 year life value is only about double the 5 year value. At 15% IRR the 20 year life is so little more than the 10 year as to be irrelevant. And the 10 year lifetime value is less than 50% more than the 5 year value. SO if you have realistic IRR;''s you need to make your money out of a 5 year lifetime (!). Maintenance obviously figures. The reason that you see so many ghost windmills when you drive through Altimont Pass is that THEY were sold as tax profit based schemes and the promoters carefully avoided factoring in maintenance costs (perhaps not in all cases) and many became uneconomic. Note that this system has a long long long experience base - they started 30 years ago (!) and the units at Sandia labs have run for many years. They are very aware of what goes wrong in real world loaded on sun 365/24 use. (They don't do anything for most of the 24 :-) ). > These farms are nothing more than a tax right off and an advertising bull= et > for the power producers. You might think that for 60 dishes at Maricopa. But they appear [tm] to have convinced large utility companies of their utility and practicability. I suggest that IF anyone is seriously considering installing 64,000 of these in one general area (several sites) then they actually expect to make a real world profit. Note that at present solar photovoltaics are only 'profitable' in the US, or anywhere else, because of tax incentives etc. That will (probably) change -but so far solar PV is uneconomic without subsidies. The notional grid-power-parity point for solar PV power systems is $1 per Watt peak INSTALLED. That translates to about 70 cents for panels and 30 cents for installation, land costs etc, I'm told. At first blush it would seem that the same costing reasonably applies to dish Stiling as well as long as all lifetime costs are factored in. In both cases the actual energy is "free". Note that solar PV also needs cleaning - as does any solar scheme. > Local, individual PV and wind power generation is the way to go, Why? What is inherently different about Stirling and similar to wind or PV. Wind power is notoriously unforgiving with cube law power increase with velocity and variable peaky output in most cases. The needs for high torque compact light weight gearboxes and leading edge blade materials has provided challenges which were hard to meet - but the industry is getting almost 'install and run' capable in many cases. High pressure high temperature Hydrogen containment is Stirling's main challenge. Tessera seem [tm] to have it moderately under control. We'll see. PV and Stirling (and thermal schemes) all depend on sunlight availability. > with nuke plants to fill in at peak load evening hours. > People need to get over themselves on the nuke issues... Coal puts more > radiation in the air every year than all the nuke plants ever have, and t= he > dust, toxins, and smog are killing far more people with asthma, lung canc= er, > and poison in the water than any nuke accident has; civilian or military. Much merit in all that. But, as with any evangelised cause (including Stirling :-) )- what they don't mention is what you need to look carefully at. For nuclear the insurance and security issues are inseparable from the costings if you want a real world comparison with other technologies. And nuclear has vastly more costs in these areas in open market conditions. After they address those they can get on to the apples against apples comparisons. If you had the choice of living within say 1 km of a large wind farm, dish Stirling farm or nuclear plant, which would you choose? (Choices will vary). It hasn't been mentioned that I've seen, but it seems to me that by raising the Stirling dishes just a little more above ground they could use the ground underneath for other purposes. Obviously much of the sun energy is taken by the dishes, BUT shadowing considerations means that enough space is left that a lot of total sun per ground area is not recovered. > Modern nukes are safer than the ones that have failed in the past. One would hope :-). > Nuke waste is a non-issue ... I'll not start to argue that here. More complex than the face value appeara= nce. > http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor Yes. I'd like to have seen that happening. Long ago and very rare apparently, alas. A few long since expired subterranean sites in ?Gabon? afair.(Underground testing perhaps :-) ). If you see 65,536 dish Stirlings (or thereabouts) installed in California I think you will be able to say that Stirlings time has come. They could join the 80,000 NZ designed Whispergen CHP Stirling units signed up for by Powergen UK for use in UK homes. Scheduled for full rollout "any time now". Made in Spain by Mondragon. Relies in government feed in tariffs and disparities in energy costs between North Sea gas and UK electricity to be viable AIUI. Will they really actually happen "any time soon"?. Stay tuned ... . Stirling's time will come. Maybe about now. Maybe not. It's far from the only solution and often not the best solution. But sometimes the sheer energy conversion efficiency, "clean" low noise operation and other factors will allow it to be best. Russell. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .