----- Original Message ----- From: "Tony Nixon" > Dal Wheeler wrote: > > If its so "trivial" one would think there would be a good many more solar > > farms out there. Same goes for wind farms. People have been working on > > these for a long time; why isn't there a more resonable return on investment > > yet if it can be done so easily? Main problem w/ solar is that most solar cells (not the newest crop, but the older ones) are extremely inefficient unless they are oriented perpendicular to the sun (hard to do for a significant period, without motorized orientation) and take an enormous amount of room to generate a relatively insignificant amount of power. Their best application is for the individual power consumer to use as roofing tiles and augment the power he buys. They are also nearly worthless during the winter and in areas that don't receive constant sunlight. In the U.S., AZ, NM, and NV are about the only places it would probably be feasible. Because they aren't as reliable as nuclear, gas, coal, or oil generators, the power company must supply some sort of backup generation for those days when the sun don't shine. Wind power is much more promising, in that a wind generator's capital investment is recovered much more quickly than with solar, they are relatively low maintenance, they work all year round in places like Wyoming. There are three very successful wind farms where I live; one on the Colorado-Wyoming border owned by Excel energy, another Excel station on I-80 in Wyoming, and one in Medicine Bow, Wy. owned by Platte River Power Authority. These each provide many Megawatts of generating capability, and nearly always are producing power. The main reason wind power is not feasible are the whiner Greeny tree-huggers who say they wreck the scenery, and think they kill whole populations of birds. I personally think they're very pretty - those giant white wind turbines going whomp, whomp, whomp - and the newer large ones kill very few birds because they are so large and turn so slowly, even in very high winds. Anyway, serves the darn birds right! Improves the gene pool :O) > I've just been hearing about an Aussie invention that claims to be able > to harness 'wind' for power generation. > The idea is to have a somewhat large diameter pipe with a turbine in it. > The pipe is long enough so that when erected into a vertical position, > the temperature difference between the top and bottom causes an airflow > up the pipe. This turns the turbine and produces power. Actually the idea is to have a giant (several km^2) greenhouse underneath, with a 1000' or so tall stack on top. The hot air generated in the greenhouse rises up the stack and turns a bunch of turbines to generate electricity. Plus, you can have all-year round food production inside the greenhouses. This is actually a very neat, very promising technology, if the whiner Greenies don't get in the way (Ooohh! ooh! you're glassing in huge areas of wild-life preserves! Waaaahhhhh!!! And that giant stack with all those horrible strobe lights on it. Waaaaaaaaaahhhhhhh!!!!) This could generate huge amounts of electricity, as you could easily have that air moving at >50 knots up the stack (even natural thermal currents in the atmosphere often move at 20 knots...channel the hot air from the greenhouse, and you can get fantastic speeds), and could have a bunch of generators in line to extract maximum energy from the rising air. Plus, this technology is very exciting to me as a soaring pilot... 20+ knot thermals with a nice 1000' marker post! way cool! 2000km cross-country, here I come! :O) - Robert -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body