Various Approaches To Hydrokinetics
Of the many dozens of articles I’ve written on hydrokinetics over the past four years since the inception of 2GreenEnergy, I’ve expressed a whole bunch of skepticism. Fans of run-of-river need to contend with the fact that, as least as far as when I do the math, the entire potential energy of the water that is falling downhill in U.S. rivers will give us about 1 terawatt (if we get every single watt), less than 20% of our total energy consumption (currently 5.4 terawatts). Supporters of tidal and ocean current energy need to believe that we can somehow mitigate the unintended consequences of inserting our “stuff” into aquatic environments, and that we can deal effectively with the “survivability” issues that come from harsh salt water conditions.
In any case, here’s a new approach to hydro – underwater “kites” – that I though readers would find interesting.
In addition, I remind readers that I think the people at Cyclo-Ocean are barking up the right tree, which is why I include them in my list of renewable energy investment opportunities.
Craig,
The article claims that the test device is 1:4 scale, and is 3 kW.
So a full scale device would be 12 kW.
12 kW for an UNDERSEA generator that must be grid connected is absurd. Even if it could operate at 33% capacity (certainly a maximum cf considering the slow an lull periods of tidal flow), then such a device would only generate ~$3500 worth of energy per year. Even if the device were free, it would take decades to recoup the install and grid-connect fees.
Obviously, they are envisioning installing undersea fields of thousands of these units… but even if you had to hire a dive team, including a licensed underwater welder and one highly qualified underwater electrician (!!), for only 2 hours per unit, it would still take years to pay back the installation costs assuming nothing goes wrong. A single maintenance issue would blow years worth of potential gain.
This is too small time to be viable for grid-connection. It’s similar per unit generation to an industrial PV panel… Imagine the economics of setting up a PV field underwater!
This just sounds like more foolishness to me.
I didn’t notice that. Thanks. I think the math on CycloOcean is a lot more encouraging.
Concerning CycloOcean, I don’t doubt that the math is more encouraging.
You’re more careful about the economic plausibility of renewable energy than any other renewable advocate I’ve read… That’s why I enjoy your blog (though we don’t always agree).
😉
Believe it or not, I just had a colleague point out that, since power varies as the square of the radius of the device, a 1:4 model will generate only 1/16th the power of a full-scale device. Having said that, I’m not sure this changes your overall evaluation too much.