Tuesday, December 2, 2008

New interest in low head hydropower.


Today I caught an AP story about increased interest in hydropower. Low head hydropower --at river locks and from 'hydrokinetic' sources -- may be something we'll see more of as energy costs rise an it becomes economically attractive.

And we'll see the inevitable conflicts over its impacts on our already strained river ecosystems.

The drawing here, from this site, is pretty typical of what I've seen. I'm no expert on hydropower, but I do know river geomorphology and some fluid mechanics, and this setup is what I'd call "geomorphically incorrect." Just the conveniently placed four foot drop in that little creekbed is unrealistic, and this setup wouldn't last a minute in any kind of flood. Maybe it's just a schematic, but probably illustrative of unrealistic expectations for this kind of power in the face of geomorphic reality.

On a much larger scale, here's Free Flow Power's website and a drawing of a system they're prototyping. The board and technical team are very impressive --clearly they're putting some serious investment into it.

All I can see are 20 foot long cottonwood snags spearing those carbon fiber turbines at 2 meters per second. But again, maybe I'm missing something.

This company is looking at installing turbines of some sort on the middle and lower Mississippi. There is a hell of a lot of energy in those rivers, but not enough, apparently, to keep them deep enough for navigation, so we burn diesel fuel on dredges to fix that. What happens to the energy these turbines extract? Maybe it could be used to charge the batteries on hybrid electric dredges.

From the AP article:

Massachusetts-based Free Flow Power Corp. is studying the prospects of planting thousands of small electric turbines in the river bed at 55 sites from St. Louis to the Gulf of Mexico, figuring together they could generate enough power to supply 1.5 million homes. The private startup says the cumulative output of 1,600 megawatts would be the equivalent of three small coal-fired power plants or one or two nuclear ones.

Some Wikipedia links on hydropower.

Also very cool link on building a pump-back demonstration model for teaching.

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