Harnessing the Tides

I saw an interesting story from the Miami Herald a few days ago:

Keys man’s dream: Harnessing the tides

KEY WEST — Douglas Bedgood recently stood on a defunct Henry Flagler railroad bridge, watching as the tide forcefully moved water from the Gulf of Mexico through a channel to the Atlantic Ocean.

What he saw was untapped energy. Enough tidal power, he believes, to light and cool every residence and business in the Lower Keys.

To capture that power and convert it to electricity, Bedgood founded Florida Keys Hydro Power Research Corp. in July. The nonprofit is working to put underwater tidal turbine farms in the Keys’ channels.

“People have been talking about this for a long time: Why not use the tides?” said Bedgood, 65. “But everybody was waiting for government or somebody else to do it. So it never got done.”

I have wondered about this for a long time as well. It seems to make perfect sense, and I didn’t understand why we aren’t exploiting this to the fullest extent. Then, I recently went to a presentation on the status of tidal energy, and found that those tides and the salt water play havoc with the equipment. The generators have to be built to withstand the most powerful tide they will ever encounter, and that drives up the cost. And on top of that, the tides still tear them up.

No offense, but I did find a bit of humor in this paragraph:

Bedgood, a massage therapist who has developed aquatic therapy devices and tried to build a wind farm in California in the 1970s, said his motive is green — but not for the color of money: “I want to do my part to save the planet.”

Finally, a few of the details:

The goal: To clump enough turbines — at least 300 — to create 160 megawatts of electricity while doing virtually no damage to the channel site or its marine life, part of Florida Keys National Marine Sanctuary.

At peak usage, the Lower Keys use 140 megawatts.

The first major step is getting the test turbine, dubbed “the football” because of its shape, into Bahia Honda Channel near mile marker 36. The turbine has four 4 ½-foot long paddles on each end to capture the tides going in and out. It will be anchored on hard sea bottom where there’s scattered small corals and no sea grass, and where the water is as much as 30 feet deep so it would not interrupt navigation, Bedgood says.

“We know it will work to get power,” said project manager Steve French of Stuart-based Applied Concepts Unleashed. “The question is how much can we get and how efficiently can we get it?”

Finally, a word about costs:

While the tides are free, producing energy from them is not.

Each turbine is expected to cost about $100,000. Bedgood said it will cost millions for the cable system and substation. To date, he has provided all the financing for his end of the project, which he expects will cost about $15 million to get the first 10 turbines up and running. He’s searching for private charitable contributors.

I hope they are successful. Tidal always seemed like a great idea to me. The devil, though, usually is buried in the details.

10 thoughts on “Harnessing the Tides”

  1. Hi Robert,

    Off Topic.

    I know that you likely won’t respond to comments, but, anyway.

    There at TOD, Rembrandt posted:

    1) Crude Oil – Latest available figures from the Energy Information Administration (EIA) show that crude oil production including lease condensates decreased by 706,000 b/d from July to August. Total production in August was estimated at 72.51 million b/d, which is 1.79 million b/d lower than the all time high crude oil production of 74.30 million b/d reached in May 2005.

    2) Total liquids – In October world production of total liquids increased by 1.4 million barrels per day from September according to the latest figures of the International Energy Agency (IEA). Resulting in total world liquids production of 86.5 million b/d, which is the all time high maximum liquids production.

    So, what makes up for the difference between crude and total liquids?

    Peak Oil means peak crude only or not?

    I’m asking because in one of your last posts you wrote about not calling peak oil yet because now a new all time high maximum had been achieved.

    Thank you very much

    Fernando

  3. Isn’t there a company that installed turbines in the East River, in NYC?

    I wonder how that’s going?

  6. Tidal energy kind of sucks because it peaks twice a day but the supply isn’t typically well matched to demand in time. Plus the timing of the peaks changes throughout the year.

    If you have storage available, it’s great, because the capacity factor is amazingly stable compared to wind or even solar. As a result, storage is generally cheaper because you need less of it.

  7. TIDES–
    one more arrow for the quiver. we may need them all. probably best when linked with WAVE energy.

    infrastructure could be problematic, especially if rise in sea levels forecaste in global warning guesses occur.

  8. i believe there is either a plan or proposal to utilize this technique using the sea level differences in panama[canal area] between atlantic/pacific oceans, but can’t remember source material.


  9. “East River Fights Bid to Harness Its Currents for Electricity” by Anthony DePalma in The NYTimes on August 13, 2007    :

    Weeks after they were formally dedicated by Mayor Michael R. Bloomberg, six underwater turbines that turn the river’s currents into electricity have been shut down for repairs and a basic redesign. The East River’s powerful tides have been wreaking havoc with the giant turbine blades since the first two were installed in December.

    … This is the reality of new energy projects, which often seem more attractive on paper than they do in practice. Verdant’s principals, along with the state officials who have supported the project with large grants, say the setback is only temporary, even expected — a way to work out the kinks before moving onto the next, expanded phase.

    Despite a string of mishaps that has taken a bit of the luster off the project, there is still sufficient optimism about tidal power to attract investments, and even some old-fashioned competition.

    It has been a rough eight months for Verdant. Days after the first two turbines were lowered into the water, the East River’s powerful currents sheared off the tips of several blades about a third of the way down.

    New blades were ordered, made of a cast aluminum that theoretically would hold up better. They replaced the ones that were broken, and were also installed on four more turbines that were lowered into the river’s eastern channel earlier this year.

    Together, the turbines were capable of producing about 1,000 kilowatt hours a day of clean electricity. But the East River tides have proved too formidable even for the stronger blades, putting excessive strain on the bolts that hold them to the turbine hubs.

    To keep them from coming apart, all six of the 20-foot-tall mechanisms, which resemble ship propellers on masts, have been shut down for repairs and may not be back in operation until November.

    “The only way for us to learn is to get the turbines into the water and start breaking them,” said Trey Taylor, the habitually optimistic founder of Verdant Power.

    …

    The project has received about $2.5 million in support from the New York State Energy Research and Development Authority, an agency that promotes energy alternatives.

    Paul D. Tonko, president of the authority, said that the technical problems had not been a major concern and that he was satisfied with Verdant’s progress. An analysis of the project’s early production record indicates that Verdant is producing energy for about 7 to 8 cents per kilowatt hour, he said, slightly higher than traditional sources at current prices for natural gas and fuel oil.

    Once the project is fully developed — Verdant plans to install as many as 300 turbines in the East River — it could generate enough electricity to power more than 8,000 homes and compete head-to-head with traditional sources, Mr. Taylor said.

    But a few obstacles still stand in the way. Mr. Taylor said the company has had to spend more than $2 million to study the impact that the turbines might have on fish in the East River. The water is monitored 24 hours a day with sonar equipment to see whether fish are harmed by the blades, which move at a comparatively languid 32 revolutions per minute.

    The company has found that the few fish who are picked up by the sonar tend to swim around the blades.

    “So far, there haven’t been any strikes,” said Ms. Gardner, the geologist who works for Verdant.

    Still, federal regulators want Verdant to conduct studies on species like sturgeon and some turtles that are rarely seen in the East River.

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