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Tidal Power a Reality

Posted by michael on from the turn-turn-turn dept.

updog writes "Here's an interesting story about a city in Norway using an underwater turbine to generate electricity. It doesn't produce much power (300kW) but maybe it'll pave the way for these types of power plants. Maybe one under the Golden Gate someday??"

4 of 343 comments (clear)

  1. Tidal Power Finally? by WatertonMan · · Score: 5, Interesting
    You do know that Canada has been producing tidal power in the Bay of Fundy for quite a few years, right? It has been putting power in the Nova Scotian grid for some time. They keep talking about making more but nothing ever comes of it.

    Here's one web page on the subject.

    Anyway the tidal power finally line is a bit inappropriate.

  2. Re:Nice but by isorox · · Score: 5, Interesting

    combine the money and the political will into orbital solar

    Ever played sim city 2000? Ever built a microwave power station? Ever had the beam slice through your airport and into a commericial zone?

    OK, a little extreme. In reality the beam would be no more powerful then a cell phone.

    I have read that Japan plans to launch one in the next 40 years. It will be capable of producing 1GW (although the article says 1GW per second ;) - same as a nuclear plant. Unfortunatly the cost per kWh is arround 2 - 2.5 times that of a nuclear plant, at the moment.

    In 40 years? Who knows.

  3. Beams are a concern, and lifetime. by Christopher+Thomas · · Score: 5, Interesting
    it's too bad all these little clean energy projects can't somehow pool their resources into building a few orbital solar satellites.

    While solar energy is a very promising option, there are a couple of catches that make it less ideal than advertised:

    • Beam intensity is high enough to cause problems.

      If your beam intensity is less than, say, the average intensity of sunlight, you might as well build photovoltaics or a solar heat engine on the ground, and save the cost of a satellite and receiving station. If your beam intensity is large enough to be useful (many times the intensity of sunlight), then it will cook birds that fly through it, muck royally with local weather (maybe even to the point of starting a local hurricane), and so forth. While these drawbacks aren't catastrophic, they have to be planned for.

      There is no danger of the beam wandering and frying the landscape. It's generated by a host of phase-locked emitters - synced to a transmitter in the middle of the receiving patch. No transmitter to sync to, and the emitters on random phases send energy in all directions, and most of it would have a hard time hitting *earth*, much less your backyard. ...OTOH, a rogue receiving beacon could really ruin a city's day.

    • Working lifetime of the satellite will be short, and revenues low.

      Not horribly short, but you're going to have to amortize the cost of the satellite over a decade or two before something wears out or micrometeorites turn your panels/mirrors into confetti. A solar power satellite costs a _lot_ to lift, and power is cheap. My own back-of-the-envelope calculations suggest it costing 10 times more to lift than would be generated from electricity sales over a decade even with very favourable assumptions (100 W wall-plug output per kg of satellite, $10,000/kg to build _and_ launch, $0.10/kw*hr sale price of the electricity).


    In summary, solar power will need several technological breakthroughs (or an order of magnitude increase in terrestrial power cost) before being competitive.

    The breakthroughs are on the horizon, though. High-efficiency photovoltaic cells are coming on to the market, and thin-film cells can already be bought over the counter. Combine this with aluminized mylar concentrating mirrors, and you might have a satellite cheap enough to lift.

    My money's still on fusion, though.
  4. Re:Environmental concerns by Bronster · · Score: 5, Interesting

    , and fish can swim around them without getting sliced up.

    But that doesn't mean they can't swim through them and get sliced up instead, does it?

    I think you're confusing low head water turbines with aircraft engines. The turbine will probably be something like a Kaplan which has big wide blades and turns at quite low speeds. Fish tend to flow straight through (though it would be rather disorienting for them I'm sure)

    What surprises me is that these things have been used for years - I'm sure I read about 5 or 6 different designs of tidal and wave based generators a good 10 years ago when I was interested in these things.

    Disclaimer - I have a lot more experience with high speed/high head impulse turbines (my father still has an original 1896 pelton water wheel with 'patent pending' on its cast iron sides - we took it out of production about 6 years ago when we decided the bearings were going through too much oil, and the new peltons could get an extra 20% efficiency, especially with specially wound low-speed alternators rather than old DC motors and v-belts)

    I'd like to see some of the more imaginative wave-power systems used though (think balloon on surface anchored to cable on seafloor with bi-directional pump and bigass spring)