CNN/Money has an informative article today about the potential of wind power:

<link>

I remain skeptical about the ability of wind or solar power to contribute a substantial portion of the world's energy needs. One reason for my skepticism is just a question of practical land area requirements.

Even the most ambitious wind farm currently being planned will only generate a peak of 4000 mW (and that's more than five times better than anyone has managed in the real world, so far), and it will gobble up a mind-blowing 200,000 acres of land. Meanwhile, the most ambitious solar plant being built (for completion in 2011) will produce a peak of only 280 mW, while using 1900 acres.

By comparison, the most powerful nuclear facility sits on about 1000 acres and produces 8212 mW. Keep in mind, that's not some ambitious projection of future generation capacity for some in-the-pipeline project, as with the wind and solar projects. Its the real-world output of an existing generation complex using today's technology.

Just as a really rough calculation, let's say that to make the world energy economy carbon neutral you need to replace an average of 13,000,000 mW of coal, oil, and gas. With the kind of nuclear facility I'm talking about, that'll take about another 1600 very large nuclear plants globally -- very ambitious, but not unreasonable -- it would be like building one such plant for every four million humans... three new plants for every two US states, for example. The combined land area it would take up would be less than half that of the state of Rhode Island.

By comprison, pulling off the same feat with massive wind farms would take 3250 farms and would take up over a million square miles of land. That's almost four times the total land area of Texas. And that assumes that you'd get the same wind efficiency average for 3250 wind farms as that one planned farm will get, which is unlikely. It will be built on one of the prime sites in the whole world for wind. The more wind (or solar) plants you build, the worse each new site will be for the technology, as the prime sites are used. Gradually you'll have seriously diminishing returns. By comparison, there are few limitations on where you can build a nuclear plant to get maximum output.

Feel free to check my number-crunching, but I think the basic point should be clear enough. In order for carbon-neutral generation to replace a serious portion of our current energy consumption (much less our future consumption, at present growth rates), we will have to be talking about some truly mind-boggling amounts of power. As such, the key concern is "scaleability." The limitations of solar and wind technology, which are tied to unusually sunny and windy locales, respectively, using current technology, limit their scaleability. Their huge land demands add an extra hurdle, making it hard to put them anywhere near places where the demand is (since the same forces that drive up energy demand in a location drive up the cost of land).

Those factors combine to mean that the more you rely on solar and wind energy, the less practical they become. You wind up building in less and less ideal locations, and transmitting the power over greater and greater distances. And that doesn't even factor in the materials cost of building these sprawling generation complexes. Nuclear power simply doesn't have the same scaleability issues.