The potential for developing tidal power in North America - particularly in Nova Scotia's Bay of Fundy - is tremendous. Researchers, the provincial government of Nova Scotia and marine energy generator manufacturers have teamed up to deploy turbines that can exploit strong ocean currents without disrupting the flow of water in the bay.
By Alasdair Cameron
Although much of the focus on tidal power has been on the eastern side of the Atlantic, the Canadian province of Nova Scotia looks set to give the old country a firm run for its money.
Most recently, in March 2012, 11 km of subsea cables needed to deliver power from the tidal projects at the Bay of Fundy's Fundy Ocean Research Centre for Energy (FORCE) had arrived. When connected, these cables will give the center a capacity of 64 MW, the largest transmission capacity for tidal power in the world, says Matt Lumley with FORCE.
Officially founded in 2009, the FORCE demonstration facility aims to take advantage of the enormous tidal potential available in the region. FORCE is in the Minas Passage area of the Bay of Fundy and features a 3,000-square-foot visitor center that was opened in November 2011. In February 2011, Atlantis Energy won the fourth and final test bed at FORCE.
Sandra Farwell, of the Nova Scotia Department of Energy, says, "The province has provided funding toward the projects, C million in total, and the central government has provided C$20 million. We've put the funding toward the common infrastructure for the site, and the players can come in and demonstrate devices. We want to be a center of excellence where people can learn and develop devices, so they can find out what works in such a harsh environment."
|This is a rendering of a 1-MW undersea turbine by Irish company OpenHydro that has been deployed by Nova Scotia Power in the Bay of Fundy. The 400-ton device was secured to the seabed with an underwater gravity base|
Every day more than 100 billion tons of seawater flows into the Bay of Fundy - more than all the world's freshwater rivers combined. Early estimates suggest that the Minas Passage area of the bay may be able to usably provide a capacity of 300 MW, while the Bay of Fundy as a whole could provide up to 8,000 MW of installed capacity.
Recognizing this huge potential, the provincial government embarked on the FORCE program in 2008 to encourage developers to test new tidal energy devices. In 2008 it declared its commitment to developing a test centre and in 2009, after a call for proposals, the first three developers were chosen. Following a survey and impact assessment, the Minas Passage area was selected for the FORCE test beds.
"We know there is more than enough (energy) to fulfill Nova Scotia's needs, so there could be an export opportunity," Farwell says.
While Nova Scotia already has one 20 MW tidal barrage system, which was constructed in 1984 at Annapolis, the current emphasis is on the development of in-stream tidal power devices that do not block or disrupt the flow of water.
The first device to begin testing in the Bay of Fundy was another 1-MW undersea turbine developed by Irish company OpenHydro and deployed by Nova Scotia Power. The 400-ton device was maneuvered into place on a specially constructed barge and secured to the seabed with an underwater gravity base.
The most recent company to be awarded a site at the test bed - Atlantis Resources Corp. - will install a 1-MW prototype turbine that is fixed to the seabed. Each of these resembles a wind turbine, with the exception that there are two sets of three blades, each mounted back-to-back to harness the tides as they ebb and flow.
Atlantis, which will work with Lockheed Martin and Irving Shipbuilding in Nova Scotia to further develop its AK-1000 device, has already tested smaller prototype machines in Australia, and is also part of the MayGen consortium looking to exploit the tides of the Pentland Firth in Northern Scotland.
United Kingdom-based Marine Current Turbines (MCT), working in conjunction with Minas Basin Pulp and Power Co., is seeking to deploy one of its SeaGen devices.
With two demonstration projects currently operational and supplying power to the grid in Devon and Northern Ireland in the UK, the company's SeaGen is probably one of the best-known tidal devices.
Sources close to the project, however, have indicated the new MCT device in Nova Scotia will be different to those currently used elsewhere. Unlike previous devices that extended above the surface, the SeaGen 'U' at Nova Scotia will be fully submersed. Importantly, though, it should be capable of surfacing itself without the need for a salvage operation every time it needs maintenance, and it will be larger than previous MCT devices, at about 2 MW.
Finally, French engineering giant Alstom is planning to conduct a trial with Clean Current Power Systems' technology. Along with the MCT turbine, this is due to be installed in 2012. Additionally, Alstom announced its plans to test its BELUGA 9 tidal energy turbine in the Bay of Fundy in 2012.
|This rendering depicts a Marine Current Turbines SeaGen marine power generator, which the company hopes to deploy in the Bay of Fundy, Nova Scotia.|
While many of these systems have been tested at various sites before, the marine environment can be harsh and challenging. According to one report, during the summer of 2010 the Open Hydro turbine had to be pulled out of the water a year early after all of its blades broke off.
Speaking at the time, Mark Savory of Nova Scotia Power said, "What comes with the world's biggest tides is a very aggressive environment. So I guess we're not terribly surprised that it is a tough place to work."
Farwell was also upbeat, saying, "The Open Hydro device, we don't see that as a failure. It's just part of the process of demonstrating. It's really about how to get these machines to work in this environment. This is a challenge for everyone."
Despite difficulties, the prize for successfully harnessing tidal power could be great. According to the International Energy Agency, the potential for tidal power is theoretically up to 2,200 TWh worldwide, of which the agency estimates about 100 TWh could be economically tapped. While this is not enough to solve the world's energy problems, in certain areas it could play an important role in providing baseload renewable energy generation, in much the same way concentrating solar thermal and geothermal power might do in other places.
The government of Nova Scotia seems to have recognized the potential to be an early mover in the industry, and the jobs and investment that this could bring. In 2010 the province announced a 40% target for renewable electricity and declared that it would be introducing a feed-in tariff for tidal energy.
The level of the feed-in tariff was set in the spring of 2011 for devices with a capacity of less than 500 kW, and a more comprehensive package of policies was introduced in the fall of that year.
"We are working on a clear regulatory environment. We're developing legislation specific to marine renewables, something we don't think exists anywhere else in the world. It's kind of unique. It will give industry a clear sense of what they have to do to get a project in the water and how to go to commercial development," says Farwell.
Cooperation is also extending across the Atlantic. FORCE and the European Marine Energy Centre announced in 2011 that they have combined research efforts to help advance development of the worldwide marine renewable energy industry.
Alasdair Cameron writes on environmental issues, including renewable energy. This article was adapted from information published on RenewableEnergyWorld.com.
Learn the latest ocean energy developments at HydroVision International
A seven-session Ocean/Tidal/Stream Power track is one of many valuable educational options available to attendees of the HydroVision International event, being held July 17-20 in Louisville, Ky.
The seven panel presentation sessions in this track feature industry experts speaking on:
- Research and Development: Moving Forward
- Deployed Projects: Experiences from Across the Globe
- The Tradeoffs between Cost, Survivability and Efficiency
- Resource Assessment
- The U.S. Permitting Process: How It has Evolved
- User Conflicts and Stakeholder Involvement
- Jumping the ESA/MMPA Hurdles
For more information or to register for the event, visit www.hydroevent.com.
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