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More wind than we thought?

July 20, 2009
Global distribution of annual average onshore wind power potential (W/m<sup>2</sup>) for 2006 (Lu et al. 2009; click image to go to source).

Global distribution of annual average onshore wind power potential (W/m2) for 2006 (Lu et al. 2009; click image to go to source).

A new study of the global potential for wind-generated electricity (Lu et al. 2009) concludes that windmills can meet the world’s energy demand with plenty of power to spare.

The open access paper in the Proceedings of the National Academy of Sciences claims that a global network of windmills operating at 20% of capacity could produce 2,470 exajoules (EJ) — about five times the current commercial energy consumption of the planet (~500 EJ). The latest estimate is much higher than the first evaluation of global wind power (Archer and Jacobson 2005), which estimated a similar network’s output at 443 EJ.

Wind resources in the US (US-DOE; click image to go to source).

Wind resources in the US (US-DOE; click image to go to source).

The paper’s state-by-state analysis of the potential for wind power in the US offers some surprises. The area where wind generation looks like a feasible alternative to fossil fuel power has grown dramatically. The old US-Department of Energy map (right) shows places like Kentucky, Tennessee, and Mississippi as blank slates of white with no real potential for wind power. The new analysis (below) colors these states yellow, and concludes that each of them could replace their fossil fuel consumption entirely with wind power and have energy to spare.

Annual onshore wind energy potential on a state-by-state basis for the contiguous U.S. expressed in TWh (Lu et al. 2009; click image to go to source).

Annual onshore wind energy potential on a state-by-state basis for the contiguous U.S. expressed in TWh (Lu et al. 2009; click image to go to source).

Building the windmill network necessary to realize this potential would be a massive undertaking. Each turbine in the network would have the capacity to generate 2.5 MW, with blades 100 m in diameter, perched on a 100 m tower. Windmills even larger are already in use. The video below shows one such windmill — the Enercon E-126 — which has a diameter of 126 m and a capacity of 6 MW.

It would be wonderful to see thousands of windmills eliminate fossil fuel consumption, but a network of such gigantic structures could have some pretty substantial environmental impacts of their own. The paper discusses the possibility that large-scale wind harvesting could alter atmospheric circulation and reduce temperatures at higher latitudes. It doesn’t mention the potential effect on birds and bats, already hit hard by habitat loss, but this article claims that large turbines are actually less dangerous to our flying friends than little ones. When I watch the slow rotation of the large windmills in the video I can see why.

While contemplating wind mega-projects, it’s also interesting to imagine what could be done at the micro scale. Large wind turbines tend to be much more efficient than small turbines. Small windmills don’t even harvest enough energy to pay back the energy used in their manufacture.

A Humdinger windbelt.

A Humdinger windbelt vibrates to generate electricity from very light winds.

Humdinger Wind Energy is a recent start-up proposing an interesting solution. Instead of small wind turbines, Humdinger proposes vibrating belts for micro-scale wind harvesting. They even offer instructions to make your own windbelt, using about $5 worth of commonly available materials.

Perhaps more of our farms should be harvesting wind, in addition to sunlight.

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6 Comments leave one →
  1. January 20, 2010 2:25 pm

    Wind Power is clean, reliable and very efficient. I think it would be great to see more dependency on this form of power in the future. Great post and keep up the great work. Thanks.

  2. November 30, 2009 9:45 am

    The ‘Humdinger’ idea is fascinating, i really get the feeling we are at a revoloutionary time for alternative energy sources.

  3. November 10, 2009 5:04 pm

    I’ve heard the US’s Great Plains are like the Saudi Arabia of untapped wind power.

  4. August 20, 2009 12:37 pm

    This is great news. Wind power is a fantastic resource for large-scale power production and the trick is to make sure you have turbines scattered all over the place – so that if you have a lull of wind in one part of the country, that is countered by the gale blowing somewhere else.

    On a smaller scale – i.e. a windmill in your own backyard – wind turbines just aren’t as effective; but that’s fine because solar does a good job of that.

    Of course, some form of large scale power storage solution would be ideal as well, so that we can store excess electricity when we are generating it…

  5. rolf westgard permalink
    July 22, 2009 7:37 pm

    They forgot a few thousand gigawatts of backup natural gas plants for when the wind is too weak or too stong.

    • July 22, 2009 7:48 pm

      Their working assumption is that the turbines operate at 20% of rated capacity, which is a realistic assumption that leaves plenty of wiggle room for wind variability.

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