The Bay of Fundy, on Canada's East Coast, has famously strong tides. An incoming tide can pull 160 billion tonnes of seawater into the bay, with a vertical range of over 16 metres, and swift tidal currents. It has the highest recorded tides in the world.
For a long time, green energy advocates have wanted to harness that powerful tide to produce energy, and now it's happening.
On Monday, a massive, five-storey-tall turbine was installed on the seafloor, and over the next few days, workers are hooking it up to the power grid via a subsea cable. It will be the first tidal array in North America connected to an electrical grid like this, and will eventually be able to power 500 houses.
Next year, another turbine will be installed. Together, they'll produce four megawatts, enough to power 1,000 homes off the strength of the tides.
Tidal energy is a promising source of sustainable electricity, but not everybody's happy about this project in Nova Scotia. Local fishers were so worried about its impact on marine life that they took the case to court, where they recently lost their bid to halt construction. (The judge said they hadn't proven the risk of irreparable harm.) A spokesperson for the Bay of Fundy Inshore Fishermen's Association told the CBC he was upset the turbine was deployed smack in the middle of lobster season, when many project opponents are away at sea.
"We know from other turbine installations around the world that fish and marine mammals are not colliding with turbines," Sarah Dawson, a spokesperson for Cape Sharp Tidal, which was selected by the Nova Scotia Department of Energy to install the test turbines, told me. "With ten years of similar devices we've installed in Scotland, there hasn't been a single incident where any marine mammal, dolphin or whale, has collided," she said. (Scotland has invested heavily in tidal energy, and recently launched the world's first large-scale tidal energy farm.)
The Nova Scotia turbines are mounted about 2 meters off the seafloor, she explained, so creatures can ideally travel under or above them. Depending on the tide, turbines are 10-20 meters below the surface, so boats will be able to pass overtop of them, too.
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"Our turbine technology is very cool and innovative," Dawson said, "but the marine technology is cutting-edge." Sonars are mounted on the turbine to detect any creatures moving through the water column. "Algorithms are programmed to identify what's moving through the water column towards the turbine," Dawson continued. "It picks up or discards what's moving [towards it], based on whether it's a living organism."
Ultimately, this trial run will help determine whether the Bay of Fundy's tides are a viable source of renewable energy. And evaluating the turbines' impact on marine life is an important part of that—for projects in and beyond Canada.
"We would like, at some point, to see more turbines in the water," Dawson told me. "We're really focused on the demonstration phase. We have a lot to learn."
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