The vast and rugged Bay of Fundy, which stretches from Maine into Canada’s New Brunswick and Nova Scotia, is home to some of the highest tides on Earth. Each day, 100 billion tons of seawater flows in and out of the bay – more than the combined flow of all the world’s freshwater rivers.
The Bay of Fundy is a prime spot for harnessing tidal energy, yet many have tried and failed.
Franklin D. Roosevelt—who summered in the area—spearheaded the Passamaquoddy Dam Project in 1935. A causeway was built between Eastport and the mainland, but the Depression soon killed any further construction and the project was abandoned one year in.
Both the Kennedy and Carter administrations looked at starting tidal energy projects in the same area, but it never came to anything, and now all that remains of these engineering aspirations is the tiny Quoddy Dam museum in Eastport.
But a little over half a century later, home-grown Ocean Renewable Power Company (ORPC) is ready to give it another shot.
Last week, the first of multiple planned tidal turbines was sent to the ocean floor and come September it will be plugged into the power grid, making it the first commercial tidal energy project in North America.
The helix shaped TidGen Power System is inspired by wind turbines and requires no dam. It’s mounted on the sea floor where it spins in the current. The first turbine generator unit has a maximum output of 180 kilowatts and will power a relatively small number of homes.
If this pilot generator can withstand the fierce Maine waters and perform up to expectations then more generators will be sunk in stronger currents over the next three years. Ocean Renewable hopes to increase output to 3 megawatts by 2016—enough electricity to power 1,200 Maine homes and businesses.
How we’re harnessing the tides today:
- Open-Center Turbines. Large underwater turbines resembling jet engines, fixed to the sea floor.
- Tidal Stream Systems. Utilize the kinetic energy from water currents to turn turbines in the same way that wind mills use air currents. Cheaper to implement and maintain and more environment friendly than tidal barrages.
- Tidal Barrages. A dam with a sluice. At high tide sea water flows into a reservoir through a one way gate. The gate closes when the tide begins to fall, and when the tide is low enough the stored water is released at pressure through turbines.
- Tidal Energy DeltaStream. Rests on the seabed without the need for a positive anchoring system. Three turbines on a single, 30m-wide, triangular frame produce a low center of gravity which stops the device overturning and sliding.
- TidEl Tidal Turbines. Consist of two contra-rotating 500kw turbines mounted on a single crossbeam. Each unit is buoyant and tethered to the seabed.
- Dynamic Tidal Power (theoretical). Long dams built from the coast straight out to sea, without enclosing an area.
Just a few years ago Maine based Ocean Renewable was a tiny start-up of three, tin cupping around family and friends for funding. “For Ocean Renewable Power Company it will mark the end of eight years of hard work and fund-raising,” said Ocean Renewable president Chris Sauer. “We are the poster child for a classic start-up company here in America.”
Tapping into “socially and environmentally conscious funds,” has given the company the foundation to move forward with the project. Private equity and federal and state funding have added up to $45 million, with over half the money coming from private investors.
Sauer admits that the tidal power project still has hurdles to overcome—like the unknown cost of maintaining the turbines—but he’s vastly confident about the future.
“We’re at a point when it’s not a question of whether our proprietary power systems work,” Sauer said. “We’ve proven that. We have to make them more efficient and cheaper.”
“The initial costs of solar and wind energy was high, but they’ve dramatically decreased today. Our projections show that by 2020 we will be competitive with any new source of power, including fossil fuel.”
Generating electricity from the tides is an attractive proposition—tides are predictable and therefore reliable, and tidal generators are buried under water so they don’t spoil the look of the wild or interfere with sea vessels. But they can be expensive and there are a limited number of places—with the right tidal conditions—to put them.
In addition, the verdicts out on whether the turbines impact marine life. Tests suggest that marine life swim around the generators rather than into them, but electromagnetic fields, noise, and machinery lubricants may all have some impact.
Do you think there’s a future in harnessing tidal energy?