Like clockwork, for almost three decades, the powerful incoming Bay of Fundy tide has flowed through a set of sluice gates into a reservoir at the foot of the Annapolis River. The gates are then closed, and as the tide recedes, the stored water falls back through a turbine, generating up to 20 megawatts of electricity for the Nova Scotia power grid.
After about five hours, the turbine stops, and the Annapolis Royal tidal power plant waits for the next tidal cycle to begin the process again.
Built in 1984, this is still the only power plant in all of North America that uses tidal power to generate electricity, and it is one of just a handful in the world.
But technology now being developed will see dozens – or even hundreds – of small turbines placed directly in the tidal flow on the ocean floor, generating power without the need for big dams and their tremendous environmental impact. In an era when renewables such as solar and wind are questioned for their lack of reliability, the predictable nature of tidal power makes it attractive – if the technology can be made cost-effective.
Nova Scotia, with its record-setting tides, could be a world leader in tidal technology. But work is progressing at a snail's pace in the province, while more investment is under way on the other side of the ocean, in Scotland and France.
The epicentre of Nova Scotia's attempts to stay in the tidal game is a stretch of ocean floor near the town of Parrsboro. Here, in the Minas Basin – a huge inlet of the Bay of Fundy – the Fundy Ocean Research Centre for Energy (FORCE) hopes to become a key centre of tidal power research.
FORCE, which is funded by Ottawa, Nova Scotia, Encana Corp. and several tidal technology companies, was established as a place to test in-stream turbines in one of the most powerful tidal currents in the world. Three of the four offshore "berths" are rented, but none of the organizations that have reserved them – French power conglomerate Alstom SA, British-based Atlantis Resources Corp, and local outfit Minas Basin Pulp and Power Co. – have yet to put a turbine in place.
FORCE communications manager Matt Lumley says the strength of the tidal current at the site makes it attractive to companies designing turbine technology, but that is also slowing down their arrival, as they want to make sure their devices are strong enough to survive. "We are sitting on the top of Everest" when it comes to tidal power, he said. "Everyone wants to come here, but everyone is also a bit nervous."
An early attempt to test a turbine in this spot did not turn out well. In 2009, Nova Scotia Power and a partner, Irish company OpenHydro, deployed a $10-million prototype turbine, but the tidal current ripped the blades off the device. Mr. Lumley insists the test was not a failure, as it successfully demonstrated the incredible power of the tides.
It will likely be 2015 before anyone tries again, and by that time underwater power cables will be in place, allowing the test turbines to connect to the power grid.
This part of the Bay of Fundy could eventually support support hundreds of turbines and easily generate 2,500 MW of electricity, enough to power a million homes, says Richard Karsten, a mathematics professor at Acadia University in Wolfville, N.S.
The development of in-stream tidal power has been slow, Prof. Karsten says, because of the difficulty in getting the technology right, the relatively low prices for conventional fuels, and lingering concerns over environmental impacts on fish, mammals, and tidal flows. But his calculations suggest that even 1,000 undersea turbines in Minas Basin would have less than a 5-per-cent impact on tide levels. "There is no indication that [developing] tidal power will have any devastating effects," he said.
Now that some big global players – like Alstom and Germany's Siemens AG – are getting into the game, the development of efficient turbines may move much faster. But those firms are concentrating their efforts in Europe, and particularly Scotland, where a supportive government has pumped money into the industry.
"The game is already lost" for Nova Scotia to become a key supplier of tidal technology to the world, said Graham Daborn, an Acadia professor emeritus who is an expert on tidal power. "Britain is much more advanced, and has a much more supportive federal government." While the Nova Scotia provincial government is supporting the sector, he said, without stronger federal backing there will be no broad tidal technology industry in Canada.
However, Prof. Daborn added, there are some specialties – such as undersea monitoring and sensing – where Nova Scotia companies are already strong, and these may thrive as the tidal industry expands globally.
A key milestone in Nova Scotia's tidal development will come this fall, when the province reveals its "feed-in tariff" rates for big tidal projects – the prices that developers will get for the power they generate. The rates need to be high enough to provide an incentive to move ahead with testing and eventual widespread deployment of turbines, without being so high as to cause a backlash among the public who will be paying through their electricity bills.
It may take time, but there will be more tidal power in Nova Scotia, insists the province's Energy Minister, Charlie Parker. "We're in a good position, and in few years time we're certainly going to have power in this province from our tidal source."
BIGGEST TIDAL POWER STATIONS IN OPERATION
Sihwa Lake power station, South Korea, 250 MW
La Rance, France, 240 MW
Annapolis Royal, N.S., 20 MW
MAJOR PLAYERS IN TIDAL POWER
Siemens: Owns Marine Current Turbines, which has had a tidal turbine operating in Strangford Lough in Northern Ireland since 2008. It has plans for several projects in Britain.
Alstom: Bought Tidal Generation Ltd. from Rolls Royce earlier this year, and is testing a one-megawatt in-stream turbine at the European Marine Energy Centre in Orkney, Scotland. If that is successful, Alstom may also try it out at its berth at FORCE in Nova Scotia.
Électricité de France (EDF): The French utility is planning a large tidal project off North Brittany, using turbines from Irish company OpenHydro. It is set to go into production in 2014
ABB: The Swiss power and automation company has bought a stake in Scotrenewables Tidal Power, which has tested a prototype floating tidal turbine
GDF Suez: The French wind and hydro giant has plans for two big tidal power projects in France, but it won't have a pilot project in the water until 2016.