The waters of the Bay of Fundy churn around PLAT-I, a tidal power generator built by the company Sustainable Marine to harness electricity off the Nova Scotia coast.Sustainable Marine Energy Canada Ltd./CP
The tidal currents in Grand Passage, between the Bay of Fundy and St. Marys Bay, flow at up to three metres a second. It was in this narrow channel, between Nova Scotia’s Brier Island and Long Island, that Britain-based startup company Sustainable Marine deployed PLAT-I, a floating platform with turbines meant to harness the tides – much in the same way wind turbines use wind.
PLAT-I was among the latest in a series of experiments that raised hopes that Earth’s expansive oceans could provide new sources of inexhaustible, net-zero electricity.
Grand Passage was intended to be a gentler proving ground before moving the platform 200 kilometres northeast to Minas Passage, a locus for tidal power developers where water flows far more quickly.
So far, however, such experiments have yielded only wreckage – both financial and physical. Deloitte, appointed receiver of Sustainable Marine in May of last year, is the latest in a long line of insolvency specialists to feast on the entrails of a bankrupt tidal energy startup.
“We don’t have any personnel left in Canada,” Sustainable Marine chief executive officer Jason Hayman said in an interview last summer. In November, its platform broke free of its moorings and ran aground.
The Sustainable Energy platform runs aground on the rocks on Brier Island, N.S., in late November. The island lies on a channel in the Bay of Fundy's Grand Passage where currents are strong, but not as fast as in Minas Passage to the northeast.Courtesy of Amy and Jess Tudor
Mr. Hayman blasted the federal Department of Fisheries and Oceans (DFO) for failing to provide permits his company needed to continue its work. DFO “was not really engaged” in attempting to understand the effects of the project, he said, nor the likelihood of adverse outcomes.
“They completely failed to do their duty as a regulator to inform themselves about it,” he said.
In response, at the Nova Scotian government’s request, last year DFO established a task force, aiming to reconcile the need to protect aquatic life with demands for faster decisions on permits. A report detailing its recommendations is expected to be released early this year.
But tidal energy faces challenges that go beyond regulations. Turbid, salty water is a formidable environment in which to generate electricity. There are only so many places worldwide where it makes any sense. And despite decades of experimentation, submerged turbines still can’t compete with their terrestrial cousins on cost.
Nova Scotia and other coastal provinces must consider whether it’s worth investing further in this promising but nascent technology – or whether to consign its wreckage to the depths.
The lure of the tides
The product of interaction between the gravitational fields of Earth, the sun and the moon, tides are predictable in a way that other renewable sources, such as sunlight and wind, are not.
Eager to add them as an option for generating emissions-free electricity, governments around the world have financed tidal power experiments. China, France, Japan, Britain and the United States have all pursued tidal to varying degrees.
As for Canada, Nova Scotia has long boasted of its “world-class tidal resource,” and not without justification. The Bay of Fundy’s tides rise and fall by as much as 16 metres. Channels such as Minas Passage – five kilometres across – or straits between islands such as Grand Passage increase current velocity, making them attractive places to experiment with tidal power.
“The equivalent of every river in the world goes through the Bay of Fundy twice a day,” said Tory Rushton, Nova Scotia’s Minister of Natural Resources and Renewables. “That’s a huge amount of force.”
That force could help Nova Scotia address several pressing problems. It’s an energy-poor province compared with others: It generated more than half of its electricity in 2019 by burning coal, and another 22 per cent from natural gas, the Canada Energy Regulator says. (At one time the province produced both in significant quantities, but its coal heyday is a distant memory, and the Sable Offshore Energy Project ceased producing natural gas in 2018.) According to an estimate from researchers at Acadia University, Minas Passage could generate as much as 2,500 megawatts at peak flows – roughly equivalent to two large nuclear reactors, and enough to meet all of Nova Scotia’s power needs.
The Fundy Ocean Research Centre for Energy, or FORCE, a non-profit, government-funded research body, was established in 2009 in Parrsboro, N.S., to facilitate tidal power experimentation. FORCE offers developers ocean real estate in Minas Passage, as well as equipment to connect to the power grid. The provincial government hoped that experimentation would lead to a commercial project generating 300 MW (about 10 per cent of the province’s needs), to be completed some time in the 2020s.
A chronology of setbacks
Yet after decades of experiments, in Nova Scotia and around the world, all that seems a distant prospect.
Early efforts to harness the tides involved building “barrages” – which are functionally similar to hydro dams – across estuaries or bays containing large volumes of water. According to the International Renewable Energy Agency (IRENA), this method still accounts for nearly all of the marine electricity generated worldwide. The world’s third-largest barrage happened to be in Nova Scotia: the 20 MW Annapolis Royal Tidal Power Plant, operated between 1984 and 2019.
But none have been built globally in more than a decade; like hydro dams, barrages are expensive to build, and there’s few appropriate sites.
More recently, startups pinned hopes on “horizontal-axis turbines.” Smaller than wind turbines, these can be mounted on floating platforms or on the sea bottom. In recent years there have been roughly a dozen such projects globally.
Typical of these was an experiment at FORCE, the Cape Sharp Tidal project, which deployed its first sea-bottom turbine in Minas Passage in 2016. It was a joint venture between Emera, owner of Nova Scotia’s monopoly utility, and Irish-owned startup OpenHydro.
But everything went wrong for OpenHydro: Just days after the company installed a new turbine in Minas Passage in 2018, its Irish parent went into liquidation. Months later, it was discovered that the turbine’s rotor had jammed. OpenHydro’s Canadian unit went bankrupt in 2019, leaving the ruined turbine on the ocean floor.
A turbine for the Cape Sharp tidal project sits at the shipyard in Pictou, N.S., in 2016.Andrew Vaughan/The Canadian Press
Afterward, the province selected a new company, BigMoon Power, to take OpenHydro’s place and remove its sea junk. BigMoon began manufacturing the first of 18 generating units – a modern adaptation of the Roman paddlewheels called the Kinetic Wheel – it planned to deploy on barges. Several other developers are active at FORCE, and some have received government funding.
As for Sustainable Marine, its joint venture received a $28-million contribution from the federal government in 2020 – which the government dubbed a “historic investment.” Nearly $22-million of that was disbursed by the time the project folded, according to an e-mailed response from Natural Resources Canada. That’s about one-third of the $60-million Mr. Hayman estimated was spent on the project.
Tidal developers face twin challenges on the regulatory front. The very nature of their work means they’re operating in areas frequented by fish and other marine life, often including endangered species. Yet their sites typically feature high currents and poor visibility, complicating efforts to prove that their turbines cause no harm.
Sustainable Marine’s environmental monitoring began in 2018; its PLAT-I platform was equipped with a variety of sensors, including cameras, hydrophones and echo sounders, all of which the company said observed no harm to marine life. Last summer, the company announced it was experimenting with fish tagging and artificial intelligence for video processing to monitor marine ecosystems.
Citing the company’s right to privacy, DFO officials refused to discuss its permits. But they noted that during the past five years, the department issued six authorizations under the Fisheries Act relating to tidal power projects.
“There are a number of proponents that have projects in various states of development in that area that we support,” said Doug Wentzell, regional director-general for DFO’s Maritimes region. “It’s very much dependent on the design, type of deployment, and how those projects will function in that environment.”
Lindsay Bennett, FORCE’s executive director, said regulatory uncertainty has plagued all developers of horizontal-axis tidal technologies. It’s not clear how they can move from single-turbine demonstrations to multiple turbines, or what monitoring they’ll be expected to perform.
“Investors need to understand what the path is for these projects to be built,” she said.
It is a formidable engineering challenge to convert movements of water within the Bay of Fundy into electrical energy without overtaxing the equipment.Andrew Vaughan/The Canadian Press
Beyond regulatory obstacles, there are the technical challenges. The whole point is to place turbines into fast-moving currents, which subject them to extreme stress.
“It all relates to the density of water,” Mr. Hayman said. “It puts quite high loads on the power capture system, so your blades experience quite large bending forces. There’s a lot of torque that you’re dealing with as well, so that’s quite hard on the gearbox.”
Corrosion is a constant threat: Lubricants must be kept inside gearboxes, and salt water out. Any equipment at the surface is exposed to everything from heavy rainfall to high winds, winter storms, hurricanes and heat waves.
Unsurprisingly, tidal projects have been plagued by equipment failures. And the deeper a turbine is submerged, the harder it is to repair. According to IRENA, technical challenges, on their own, helped bankrupt several startups.
Mr. Hayman said such technical challenges are by no means insurmountable. By the time Sustainable Marine went bankrupt, it had overcome many.
“Very rarely did it take us more than two or three goes at something to get it figured out,” he said. “We’ve already been through a third iteration of the blades, a third iteration of the drive train. So the actual powertrain side of it was pretty smooth.”
One of Sustainable Marine's older platforms is hauled out of Grand Passage in April, 2023, to be dismantled, while PLAT-I, in the background, waits to be towed to secure storage in West Port harbour.Sustainable Marine
Perhaps the greater challenges, then, are financial. The costs of specialized equipment required for tidal power tend to be high, making it substantially more expensive than other renewables.
In a report, IRENA observed that despite “countless” attempts, evidence for the viability of tidal power projects remains wanting. “With highly anticipated players repeatedly filing for bankruptcy while having successfully deployed large turbines and having hundreds of megawatts in the pipeline, the case arises that the value proposition of tidal stream technologies and horizontal-axis turbines, in particular, may not be strong enough.”
Mr. Rushton said he’s been told that costs could fall to 15 cents a kilowatt hour, on par with coal-fired generation – a tantalizing prospect.
But he added: “We’re producing electricity with onshore windmills at 5-cent kilowatt hours. I’m being told that the energy being produced on the trials in the Bay of Fundy are upwards of 35- or 40-cent kilowatt hours.
“There’s still a ways to go.”
At least for the moment, tidal power remains dependent on continued government support.
“Similarly to how wind and solar energy were brought to market, ocean energy needs clear signals from governments to provide visibility about the future market to private investors,” IRENA urged in a report last year.
Mr. Rushton said he foresees tidal energy playing only a small part in meeting the province’s renewables targets during this decade. But his message to developers is that Nova Scotia’s enthusiasm for the technology remains undiminished.
“Our door is open for business,” he said. “We want you to come here. We want to be that test area.”
Mr. Hayman said only two jurisdictions provided the consistent support and subsidies necessary to advance wind power: California and Denmark. In his view, no jurisdiction – including Nova Scotia – is doing that for tidal.
“It really does worry me,” he said. “Without the right sandbox, it just won’t launch.”
Editor’s note: A previous version of this article stated incorrectly that the first Cape Sharp Tidal turbine was deployed in 2015. It was deployed in 2016. The story also stated incorrectly that FORCE selected BigMoon Power as a berth holder. In fact, the Nova Scotia governments selects berth holders at FORCE.
Matthew McClearn