Can Tidal Power Be a Contributor to the Grid?
Seventy-five years ago, President Franklin D. Roosevelt tried to harness the power of tidal energy off the coast of Eastport, Maine, for electricity. But, according to Green Techno, the project went bust, drowning in a sea of red ink.
But that was then, this is now. Ocean Renewable Power Co. says it knows how to succeed where FDR failed. Whereas Roosevelt proposed a massive construction project, as part of its New Deal economic plan, ORPC is focusing on technology for the first tidal energy project in North America, and it is expected to actually add power to the grid.
ORPC did not respond to e-mail requests for information, but as Green Techno reports, the mouth of the Bay of Fundy, where the project is located, has “the greatest tidal movement of anywhere in the world.”
According to ORPC officials, 100 billion tons of water flow in and out of the bay daily, “with the force of 8,000 locomotives and tidal ranges of up to 50 feet or more.” The Maine Tidal Energy Project is a three-part project, which when complete will include power systems in Cobscook Bay, Kendall Head, and Western Passage and contribute energy to the Bangor Hydro utility grid.
The project places turbines, “made from racing boat material and shaped like airplane wings,” according to Green Techno, below the surface of the water to convert the energy generated from the movement of the water into electricity. The project is expected to power 1,200 homes in three years.
As local news outlet Bangor Daily News notes, the Maine Tidal Energy Project has been an eight-year undertaking and is currently in final test phase, with an Oct. 1 go-date to harness energy from the sea.
Since 2004, the Eastport-based Ocean Renewable Power Co. has been engineering, fabricating and field-testing submersible turbines that convert tidal currents into kilowatts that can be sold to electrical utilities.
John Ferland, ORPC’s vice president of project development, described the company’s proprietary technology, the TidGen system, to the Bangor Daily News as a rectangular, cross-flow turbine that resembles a paddle wheel. With each turbine at 98 feet wide and 17 feet deep, a system of turbines can generate as many as 150 kilowatts of electricity with a six-knot tidal current, the paper reports.
In a Green Techno video, Chris Sauer, ORPC’s president and CEO, admits that the company isn’t turning a profit yet and is, in fact, relying on a $10 million grant from the U.S. Department of Energy. While optimistic about the technology’s potential and what ORPC can do with it, he hedges his bets a bit, claiming only that he hopes to be “competitive” with other renewables by 2020 against solar or wind.
Which, of course, neatly sidesteps the vexing question facing any renewable energy source: Will the energy be produced at a competitive cost versus traditional energy sources such as coal or natural gas?
ORPC has seen some success. Company officials point out that in 2008, they were the first concern to generate electricity from the Bay of Fundy’s tidal currents without the use of dams, proving that their turbine generator unit was a technical success.
Of course, with the sea’s tremendous power potential, Sauer and ORPC are hardly the first to attempt to realize it. According to industry advocate site Maine Tidal Power, there used to be quite a few tidal mills along the Maine coast — as far back as the late 19th century. If they chose the right sites, Maine Tidal Power says, mill operators could store potential energy that could be converted to kinetic energy with the receding tides. Or the currents could be combined with river flow to turn paddle wheels if tides weren’t available.
A later New England-native president, John F. Kennedy, resurrected Roosevelt’s Cobscook Bay project in the 1960s, with the intent of combining tidal power with a pumped storage project for the generation of continuous power but was defeated, according to Maine Tidal Power, by “the scale of the project and concerns associated with public utility integration combined with environmental issues.”
In the 1970s, during the energy crisis, there was another project to harvest energy from the water that was deemed technically feasible but marginally viable on economic grounds due to the fee structure established in Maine for renewable energy projects during the early 1980s, according to the advocate website.
Maine isn’t the only place with the possibility of allowing tidal power to be harnessed for energy. There are estimates that tides could provide around 20 percent of Britain’s energy needs, with projects around the Severn, Dee, Solway and Humber estuaries. But according to British website Energy Resources, only around 20 locations in the world have been identified as possible “tidal power stations.”
The U.S. Department of Energy has high hopes for tidal technology and the Maine project. At the direction of the Maine Public Utilities Commission, three of the state’s electricity distributors will purchase electricity generated by the ORPC pilot project. The DOE website says once finalized, the contracts will be in place for 20 years. They are the first long-term tidal energy power purchase agreements in the United States.
Tidal power has many benefits. The turbines are under the water and thus not eyesores, and the source is infinitely renewable and free, with virtually no harmful emissions. It is said to be more reliable than wind or solar, with relatively low overhead and operating costs. But there are some drawbacks.
According to the Climate Institute, a fairly obvious disadvantage is simply putting barriers into waterways in the first place.
The highly diverse estuaries that are often most feasible for tidal power sites can have adverse effects on natural habitats by impacting sedimentation and erosion, water flow, salinity and overall water quality.
And there’s the problem that solar power faces: Power generation cannot be synced with human demand — the way it is possible fossil-fuel-powered plants. The optimal times of day for tidal power generation are not in sync with human demand, the institute notes, adding that the ideal tidal sites may not be located in areas where electricity demand is high. From Maine, running the generated power to population centers would be expensive.
And would there be climate change effects — specifically weather events such as storm surges, tidal flooding and droughts?
Bear in mind that tidal power, as a method of contributing to the grid, is still in its infancy technologically. All technology that exists today is experimental. And from a business perspective, investors may go after more lucrative short-term investments rather than put up a lot of money now and wait a long time for the returns of an established technology.