| | There are actually a lot of clean, safe sources of power out there. One of the scientists on a panel at the most recent LOSCON sf conference mentioned that in areas where you have fairly constant high winds, you don't need multi-million dollar wind turbines. You simply spray charged water droplets into the air, let the wind drive them away from a charged fence and then recover them with another fence, completing the circuit.
Another, somewhat more ambitious kind of design that was the main focus of the panel was the use of either heat driven or evaporative towers. Structural costs could be minimized by using the sides of local mountains as the major support. In the heat-driven design, an enclosed air mass is simply heated by the sun shining on a black surface, which could be paint on the mountainside under the plastic shell that enclosed the air. The hot air rises through the enclosure and drives a wind turbine. The larger such a system is, the better it works. However, it has two downsides. First, it adds heat to the general ecosystem, as naturally you want the blackest surface possible, and of course it requires sunshine to function at all.
A more versatile system was on the cover of the one of the popular magazines a couple decades ago. Instead of simply enclosing air and heating it via sunlight, this system did just the opposite. Sea water is pumped up to the top of the tower and sprayed into the top opening. As it evaporates on the way down, it cools the air, causing it to become more dense and thus heavier, which means that the energy required to pump the water up there is multiplied several times and recovered again via turbines. Such a system can operate night or day so long as the air temperature is substantially above the freezing point, although again it has to be quite large to function efficiently. However, presumeably, since there is little to support other than the air enclosure itself, the design that was shown - made out of brick and several hundred feet high, could be supplanted with a Bucky Fuller tensegrity structure using thin silver-coated polyethaline or reflective mylar, or some similar thin, cheap, highly reflective sheeting, weighing very little and using minimal material.
As an added benefit, at the bottom of the water cooler design, you have cool, moist air and a fallout of sea salt, or whatever solids are dissolved in the spray water. The original article pointed out that in the areas where there is the best hot, dry air, you could then direct the cool, moist air into a surrounding hot-house to help grow crops that otherwise could not tolerate the extreme dryness or not without a LOT of irrigation.
|
|
