Yet Another New Energy Source

Putting the vortex to good use!

As the world economy continues its wide swings mired in uncertainty as well as hope that the necessary changes in the way we energize our world will finally get a real chance for development, scientists at the University of Michigan, funded by the US Department of Energy, have developed a new technology inspired by the way fish swim that can harness the power of slow-moving water.

Most hydropower technologies rely on the action of waves, tides or faster currents caused by dams, and need the water to move as fast as five or six knots in order to operate efficiently. This new system can generate electricity in water that flows less than one knot (about 1 mile per hour), and does not require placing obstructions in or on top of the water as other methods do. Rather, this new system uses cylinders positioned horizontal to the water flow and attached to springs beneath the surface of the waterway. As the water moves past the cylinders, it creates vortices which push and pull them up and down on the springs. It is the mechanical energy in the vibrations that is converted into electricity.

The scientists published their work in the current issue of the quarterly Journal of Offshore Mechanics and Arctic Engineering, and are busily constructing a prototype in the Detroit River – which has a flow of less than two knots. They estimate that this technology would require up to 50 times less ocean acreage as wave power generation systems, and could work in places such as the English Channel, which enjoys quite a strong current, without offering any surface obstructions to shipping lanes or even to picturesque views from the shore.

UM professor of naval architecture Michael Bernitsas calls the system Vivace, or “vortex-induced vibrations for aquatic clean energy.” He explains the inspiration of how fish curve their bodies to glide between the vortices created by the bodies of the fish swimming in front of them. “Their muscle power alone could not propel them through the water at the speed they go, so they ride in each other’s wake,” says Bernitsas.

The really exciting thing is how much power this fairly simple technology could potentially produce. A field of cylinders installed on a sea or river bed and taking up just 1km by 1.5km and about the height of a 2-story house could convert a slow three knot flow into enough electrical power for 100,000 homes. Small systems with just a few cylinders stacked like a ladder could be used to power lighthouses or ships at anchor. Once developed fully, the power would be cheaper than wind, and much cheaper than solar.

Now, this technology isn’t going to make my homestead energy independent any time soon, given that I’ve just two mountain creeks barely deep enough for trout and crawdads, so I’m better off just building a small dam or sluice and installing a turbine just big enough for my needs. I can supplement with solar, both for generating power and for passive uses (water heating, heat gain in the cabin, etc.). But even in my fondest dreams I’m wanting to take Duke Energy up on their backwards meter deal so they have to buy my excess “green” production when I’m not using it all, and I can get electricity from the grid even when my systems go off-line. For the big power companies who trade energy per demand through the grid, this new hydropower technology could make a big dent in our future needs.

So… all we need to figure out once we’ve got all our alternatives in rapid development, is how to fix our antique grid! I’m sort of hoping they’ll opt for a wireless system of some sort, maybe re-discover some of Nicholai Tesla’s very interesting ideas about that. We’re busy getting wireless service for our computers and cell phones, surely it can’t be that hard to figure out an application for electricity. Or is it? Hmmm… guess I’ll have to look into that and report back!

Telegraph: Ocean currents can power the world

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Filed under Alternatives, Energy, Environment, Water | Comment (1)