Harnessing the tides: The future of renewable energy could begin in Cape Cod Canal
BUZZARDS BAY — Attached to a metal pole, a small tidal turbine resembling a metal rocket ship was placed Tuesday morning under the ripping currents of the Cape Cod Canal.
The tidal turbine could be the start of another form of renewable energy that would be able to provide electricity for decades to come.
“It’s an industry that is well-poised to take off,” said David Duquette, CEO of Littoral Power Systems Inc., based in New Bedford, that provided the model tidal turbine for the demonstration Tuesday. “But it does have some cost constraints, which is why we are looking at things such as saving costs on civil works.”
The tidal turbine, which was not producing electricity, was the first of its kind to be tested on the Bourne Tidal Test Site structure situated next to the railroad bridge near the Buzzards Bay side of the canal. It will be monitored using a camera system to see if it will affect fish and marine wildlife in the area.
“We wanted to spin up something in our backyard here — we’ll do it,” said Duquette before the turbine was launched.
The next generation of the device being tested in the canal will be deployed to Fairbanks, Alaska, where it will be tested in a “mightier” river, Duquette said.
On Monday, two sensors were installed to monitor water conditions and fish behavior. Since video cameras require light to work, which at night would affect fish behavior, an acoustic camera was also deployed.
The model tidal turbine was due to remain in the water for about 48 hours as cameras watch how it affects the environment around it, said John Miller, the New England Marine Renewable Energy Collaborative executive director.
In past experiments, such as in Scotland or in the East River in New York, cameras have found that fish generally avoid the turbines, Miller said.
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“I like to say (after) evolution through a billion years, fish have developed to work in the ocean. (When they see) a big thing with teeth, they know how to avoid something like that,” Miller said. “We still need to monitor that.”
Tidal turbines are similar to wind turbines in that they have blades that turn a rotor to power a generator, according to the U.S. Energy Information Administration. They can be placed on the sea floor or a river where there is a strong tidal flow. Because water is about 800 times denser than air, tidal turbines have to be much sturdier and heavier than wind turbines.
There are small test sites and there are big test sites for full-scale tidal turbines, Miller said. There have been instances in which turbines in a smaller tank have had their blades fall off when they are brought to full scale, he said.
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“They knew there was a need for something in-between,” Miller said. “This was designed to test something in the order of 10 feet in diameter.”
As a solution, the energy collaborative installed the Bourne Tidal Test Site in 2018, and in 2019 got it up and running, said Miller. In 2020, the test site had two turbines scheduled to come, one from Canada and the other from California, but due to COVID-19 concerns, both plans fell through, he said.
The Cape Cod Canal has water traveling at around 4 to 5 knots, Miller said.
“They say a 6-knot current force is equivalent to 400 mph wind,” Miller said. “They are testing these things in northern Canada and Ireland; they are basically developing them in a hurricane.”
Tidal turbines are able to power a lot of energy and electricity, but it is a tough environment and it is costly to build something to survive in that environment, Miller said.
“You have to build something like a battleship, but battleships aren’t the most efficient things,” he said.
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Engineers can build something to survive anywhere, Miller said. But you don’t want to put that much money into something that might not efficiently produce electricity, he said.
Why tidal turbines?
As a future alternative energy resource, tidal turbines are attractive for a couple of reasons, Miller said. The No. 1 reason is that they are predictable, he said. One can monitor the tide for hundreds of years ahead of time.
Secondly, “they are out of sight, out of mind,” with most developers designing them to be under the water, he said.
“In theory, (tidal turbines have) a tremendous amount of promise,” Duquette said. “That is a great promise — it is suitable for (energy) baseload unlike other renewable energies like solar and wind farms. It is too early to say whether the promise of all of that can really be extracted.”
The demonstration was funded by the Seaport Economic Council. The grant to fund the test site is through a partnership between the Falmouth Economic Development Industrial Corporation and the energy collaborative.
It cost about $400,000 to install the test site, Miller said. The amount is a fraction of the cost of other test sites around the world that cost $30 million to well over $50 million, he said.
“We get the state, the Commonwealth, into this business with this technology without the really extreme costs,” Miller said.
Tidal turbines are about 10 years behind wind development, Miller said. The advantage that wind had is that it was able to start small and scale up. Due to the high costs involved in tidal energy, companies went straight to the big scale, creating a much bigger challenge, he said.
The energy collaborative is a nonprofit corporation that educates and involves all stakeholders in the marine industry to promote the sustainable development of renewable energy in New England ocean waters, according to its website. The group spearheaded the movement to get the test site on the canal.
Before the tidal turbine was tested, local companies have used the site to monitor underwater test sensors, Miller said.
The nonprofit is working with OpenCape to get broadband installed on the testing platform, Miller said. In past testing, sensors were using WiFi to transmit data, but it overwhelmed the system, he said.
The energy collaborative is working on adding power to the platform, Miller said. Previously, they used a solar panel and battery to operate it, he said.
In addition, getting power to the platform will act as a two-way street for getting power off the platform and onto the grid from the tidal turbines, Miller said.
The companies building the turbines want to be able to say to investors that "they were able to put electrons on the grid," Miller said.
