Tide Power

Postby Pit♥bull » February 1st, 2009, 3:59 am


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By Alex Morales

Jan. 30 (Bloomberg) -- Three decades ago, engineer Peter Fraenkel created an underwater turbine to use river power to pump water in Sudan, where he worked for a charity. Civil war and a lack of funding stymied his plans. Now, his modified design generates electricity from tides off Northern Ireland.

“In the 1970s, the big snag was the market for that technology consisted of people with no money,” said Fraenkel, the 67-year-old co-founder of closely held Marine Current Turbines. “Now it’s clear governments are gagging for new renewable energy technology.”

MCT last year installed the world’s biggest grid-connected tidal power station in Strangford Lough, an Irish Sea inlet southeast of Belfast. The SeaGen project’s two turbines, which cost 2.5 million pounds ($3.6 million), can produce as much as 1.2 megawatts of electricity, enough to power 1,140 homes.

The company is one of more than 30 trying to tap tidal currents around the world, six years after the first project sent power to the grid. Investors may pump 2.5 billion pounds into similar plants in Europe by 2020 as the European Union offers incentives for projects that don’t release carbon dioxide, the gas primarily blamed for global warming. In the U.S., President Barack Obama plans to increase tax breaks for renewable energy.

“Tidal energy has an enormous future, and the U.K. has a great resource” if construction costs come down, said Hugo Chandler, renewable energy analyst at the Paris-based International Energy Agency, which advises 28 nations. “Its time may be just around the corner.”

Startup Costs

While tides are a free source of energy, generating power from them is three times more expensive than using natural gas or coal over the life of a project, according to the Carbon Trust, a U.K. government-funded research unit.

Including capital expenses, fuel and maintenance, U.K. tidal current power costs 15 pence per kilowatt hour, compared with 5 pence for coal and gas and 7 pence for wind, the trust says.

Designing equipment to survive in salty, corrosive water and installing it in fast-moving currents boosts startup costs, said MCT Managing Director Martin Wright, who founded the Bristol, England-based company with Fraenkel in 2002. MCT raised 30 million pounds for SeaGen and pilot projects, he said, declining to break out the expenses.

Gearboxes and generators have to be watertight. The machinery must withstand flows up to 9.3 knots (10.7 mph) in Strangford Lough, which exert three times the force of projects that harness wind at similar speeds, Fraenkel said.

“The forces you’re trying to tap into are your enemy when it comes to engineering the structure,” said Angela Robotham, MCT’s 54-year-old engineering chief.

135-Foot Tower

The project consists of a 41-meter (135-foot) tower with a 29-meter crossbeam that is raised from the sea for maintenance. Attached to the beam are two rotors to capture incoming and outgoing flows. The turbines convert the energy from tidal flows into electricity, differing from more established “tidal range” technology that uses the rise and fall of water.

SeaGen operated at full capacity for the first time last month. The turbines are generating intermittently as engineers carry out tests and scientists monitor the effect on wildlife.

Positioned between the North Sea and Atlantic Ocean, the British Isles have about 15 percent of the world’s usable tidal current resources, which could generate 5 percent of domestic electricity demand, the Carbon Trust estimates. Including wave power, the ocean may eventually meet 20 percent of the U.K.’s energy needs, the government said in June.

Theory to Reality

Grid-connected tidal power moved from theory to reality in the past decade, with the construction of smaller, test projects.

OpenHydro, a closely held Dublin company, linked a donut- shaped device with less than a quarter of the capacity of SeaGen to the grid at the European Marine Energy Centre in Orkney, Scotland, last May. Hammerfest Strom AS, whose owners include StatoilHydro ASA, in 2003 made the first tidal turbine connection with a 300-kilowatt project near Hammerfest, Norway.

The Carbon Trust says developers in Europe may build 2,500 megawatts of tidal current capacity, enough to light 2.4 million homes, at a cost of as much as 2.5 billion pounds.

Dusseldorf-based E.ON AG, Germany’s largest utility, is spending 500 million pounds to build a 1,275-megawatt gas-fired power plant in southeast England. At that price, tidal power is about 2 1/2 times more expensive per megawatt than gas.

“It’s as expensive as it could possibly be at the moment because we’re at the earliest stage,” Fraenkel said. “Once we’re able to go for bigger projects, the cost will come down.”

Government Incentives

Across the Atlantic, the Obama administration’s stimulus program may help boost investment in green power. Lawmakers have added about $20 billion in tax credits to subsidize producers of renewable energy as part of the economic recovery bill currently being considered by the U.S. Congress.

To promote tidal energy, the U.K. is giving utilities that buy electricity from projects such as SeaGen double credit toward meeting their renewable energy targets. The EU plans to get a fifth of the energy it uses for power, heat and transportation from clean sources by 2020.

Such programs may mitigate the effect of the economic slowdown on tidal projects, said Stephan Gueorguiev, an associate at London-based Advent Venture Partners, which manages more than 500 million pounds. The company has assessed at least 10 tidal and wave energy developers and invested in one.


“Backing these companies already has a significant amount of risk, so the additional risk of this financial crisis isn’t that great,” Gueorguiev said. “Government support counterbalances the financial crisis.”

Next year, OpenHydro plans to install three one-megawatt turbines off the U.K.’s Channel Islands and another in Canada’s Bay of Fundy. The ScottishPower unit of Bilbao, Spain-based Iberdrola SA said Sept. 29 it may install as many as 20 one- megawatt Hammerfest Strom turbines at each of three sites by 2011, possibly creating enough power for more than 40,000 homes.

MCT is also working with RWE AG’s Npower Renewables to build a 10.5-megawatt tidal farm off Anglesey, Wales, by 2012.

“Fossil fuel represents burning off the Earth’s capital, and now we’re going back to the energy that’s available to the planet in the course of the day,” Wright said. “Tidal stream energy is no longer a nice-to-have. It is a must-have.”
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Postby pitbullmamaliz » February 1st, 2009, 9:28 am

Neat idea, seems a bit cost-prohibitive still.
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