DEC 30

Hydrokinetics literally refers to the process of generating electricity by harnessing the motion of water. It’s nothing new; hydroelectric power plants use this very principle. However, it seems that we’ve picked most of the low-lying hydroelectric fruit, and now the focus shifts to capturing the power in oceans and rivers.

A whole slew of ocean/wave power technologies is being developed, and although they haven’t come to reality just yet, there is a lot of potential – mostly because the ocean is huge, and as long as a technology can be brought to scale, the general consensus is that there is plenty of energy to tap.

River hydrokinetics, on the other hand, seem to have hit some snags. The principle is essentially the same – build some kind of turbine that is pushed by the current of the river. The difference is that they usually produce less power. More importantly, building them is a regulatory nightmare, since companies trying to put them underwater are legally treated as if they were building a hydroelectric dam (which, as you can imagine, is not simple).

Take Hydro Green, a company that just installed the nation’s first hydrokinetic turbine in Minnesota, under the Mississippi River. It works, and it’s green… but it only generates 35 kilowatts. Maybe this was just a prototype; maybe newer models will generate more electricity. But if you are going to have to build more than 40 of these things just to get the same amount of energy coming out of, say, one of GE’s 1.5 MW wind turbines – you have to wonder about the pros and cons.

Verdant Power is another example – they’ve been working on putting turbines like this in the East River of New York City for years. According to a researcher at the Electric Power Research Institute, they have spent more money on permits than they spent on actually building their turbines!

I’m not saying that putting turbines in rivers doesn’t make sense BECAUSE there is red tape. But every idea needs to pass a cost-benefit analysis, and given the various costs of building turbines in slow moving rivers, I wonder whether the ultimate benefits would really outweigh the costs. There may be more to gain from the ocean.

Via WIRED

Comments (4)

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Its about your energy portfolio
written by Dai, December 30, 2008

Its clear that not all rivers are suitable for placing turbines in. Large rivers which maintain a pretty constant flow throughout the year are energy sources which should not be ignored however. Even if the turbines dont produce as much energy as wind turbines, at least they will be producing the energy all year round, without depending on the winds fluctuations. Of course, this is the same for turbines in oceans. For large rivers its understandable that there will be a lot of red tape, but as far as whether the benefits will outweigh the costs, surely the benefit of constant, renewable power, is worth all the hassle and bureaucracy that will inevitably be incurred. Its up to governments to realize their assets and simplify the complex planning system, so that the costs are reduced and barriers to progress removed.

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written by Clinch, December 30, 2008

The thing that worries me about completely harnessing a rivers power, is the same problem with wind turbines, but with fish flying in to the blades, rather than birds.
And there's also the possibility of seaweed (er, riverweed) entangling the turbines.

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written by Miltowny, December 31, 2008

Kinda creeps me out.... since I grew up swimming north of there in the St. Croix.

I hear great things are coming with this. Other applications are tying into high pressure flows off of water tower pipes and etc. Sounds stupid, but since the water is already flowing.... it might work as a small source.

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Red tape is man made - not inevitable
written by Fred, January 01, 2009

What creeps me out is people who unthinkingly assume that "the government" should be in charge of all our lives!

Bureaucracy is a necessary EVIL, made by man, and we should seek always to minimize it as we go about our productive and creative lives.

Note: rotary motion turbines are not the only possibility for generating water power. Wave motion works very well in nature. Remember the UMich professor and his Detroit river test? I suspect this kind of device would have far less impact on the fauna - but a Tesla turbine, rather than the conventional design pictured above, probably would, too.

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