This summer I attended the GOMI summer workshop at Acadia University and was able to interview professors and listen to presentations concerning tidal power. Evident by the work being done in Nova Scotia, fossil fuels have become a less viable energy source for the future causing scientists to start looking for new forms of renewable energy such as tidal power. For years now, researchers have been testing the potential of tidal power in the Bay of Fundy, adjacent to Nova Scotia because the tides there are the greatest in the world reaching 53 feet (16 meters). Tidal power converts the energy obtained from the tides into electricity. Not all tidal power stations are the same. For instance, unlike many other turbines that operate one way, the Nova Scotia turbines both as work the tide goes in and out. Therefore, they are operating 80 to 90% of the time. In other locations, turbines only convert the power from outgoing water, and are only operating 30% of the time. The benefit of tidal energy over wind or solar is that it is much more reliable since it is known when the tide comes and goes every day. However, there is opposition and concerns regarding the effect tidal turbines will have on fish and the ecosystems.
The turbines in Nova Scotia are still in the testing phases, and the influence they have on their surrounding environment is being closely monitored. These turbines cannot be tested in labs because it is impossible to simulate the harsh conditions of the tides in the Bay of Fundy. The most recent design was removed last spring because it kept breaking and needed regular fixes. In the Minas Passage, the location of interest in the Bay of Fundy, the flow rate is roughly six meters per second. This incredibly fast water, combined with the turbidity and the amount of particles in the water can damage the turbine, for the abrasion caused by particles wears down the turbine. These conditions make it significantly harder to track the organisms and to obtain high-quality data on the turbine.
In theory, a single turbine is comparatively very small in relation to the rest of the bay. The turbines have been known to create pressure domes making the fish more likely to flow over the turbine. At a turbine site in Cobscook Bay in Maine, a recent study was conducted to assess the effect turbines would have on fish. The components they studied included hydrodynamic, how the turbine manipulated water flow; and acoustic output, the sound produced by the turbine, and potential fish kill. Through the use of hydroacoustics, they located at what level of the water the majority of the fish were found and if these fish encountered the turbine how they would react: whether they went over it, swerved last second in avoidance, passed through, or were hit. They were able to find that the probability of a fish encountering the turbine was only 3% and the chance they would get hit was even less.
Tidal power is still pretty far from commercial development since it is very costly and the ideal design has not been found. Tidal power has a lot of benefits such as a low carbon footprint, but there are only a few places in the world where the tide is great enough for it to be practical.
I was lucky enough to be able to interview Dr. Anna Redden, a professor at Acadia University and the director of the Acadia Tidal Energy Institute. She believes that tidal power has the potential to provide 10% of the Nova Scotia’s future energy. She explains how “tidal energy is only available in a small number of places globally and if it can be harnessed sustainably in those places, it can contribute a large percentage of the local area’s energy needs, but on a global level, it’s potential is small.” Redden argues that the Bay of Fundy has been the ideal place to test since “the wow factor of the locations gets funding for the project.” Although tidal power is not ready to be commercially used, it does have the ability to provide significant amounts of energy in places with large tides including various locations along the Gulf of Maine.
It’s important to remember that most places are looking to have as much diversity in their energy resources as possible, so they are not relying on one source.
Grace Ellsworth is a senior at Newburyport High School in Massachusetts and has been a member of the Newburyport GOMI team for three years. This summer Grace served as an intern at the US Fish and Wildlife Parker River Wildlife Refuge, Newburyport. She has, over high school years, worked on related projects including Climate Change Cafe (community dialogues on local effects of climate change) and invasive plant species. In the summer of 2017, she attended the GOMI Learning to Steward the Gulf conference in Nova Scotia as a Newburyport team student representative. Next year, Grace plans on pursuing environmental science and conservation at a liberal arts school in New England.