Geothermal, Hydropower

Nova Scotia Joins Surge on Tidal Power

To date much of the focus on tidal power has been on the Eastern side of the Atlantic with demonstration projects in Scotland and Northern Ireland. Over on the Western side however, the Canadian Province of Nova Scotia looks set to give the old country a firm run for its money.

The latest step forward came in February 2011 with the announcement that Atlantis Energy had won the fourth and final test bed in Nova Scotia’s demonstration facility – part of the Fundy Ocean Research Centre for Energy (FORCE).

Officially founded in 2009, FORCE aims to take advantage of the enormous tidal potential available in the region.

Sandra Farwell of the Nova Scotia Department of Energy said that the project is “well underway.”

“The Province has provided funding towards the projects, CAN$7 million in total, and the Central Government has provided CAN$20 million,” she said.

“We’ve put the funding towards the common infrastructure for the site, and the players can come in and demonstrate devices. We want to be a centre of excellence where people can learn and develop devices, so they can find out what works in such a harsh environment,” she explained.

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 may be able to usably harness 300 MW of electricity, while the Bay of Fundy as a whole could provide up to 8,000 MW of installed capacity.

Recognizing this huge potential that the Bay could provide, the Provincial Government has 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,” commented Farwell.

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 in the bay.

The first device to begin testing in Fundy was another 1 MW undersea turbine developed by Irish company OpenHydro and deployed by Nova Scotia Power. The 400-tonne device was maneuvered into place on a specially constructed barge and secured to the seabed with an underwater gravity base. (See Openhydro image, above.)

The most recent company to be awarded a site at the test bed – Atlantis Resources Corp. – will prototype a 1 MW  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 successfully prototyped smaller machines in Australia, and is also part of the MayGen consortium looking to exploit the tides of the Pentland Firth in Northern Scotland.

UK-based Marine Current Turbines (MCT), working in conjunction with Minas Basin Pulp and Power Co. is seeking to deploy one of its SeaGen devices (see image, below). With two demonstration projects currently operational and supplying power to the grid in Devon and Northern Ireland in the United Kingdom, the company is probably one of the best known tidal devices.

Sources close to the project however have indicated that the new MCT device in Nova Scotia will be different to those currently in use 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 will be larger than previous MCT devices, at around 2 MW.

Finally, French engineering giant Alstom is planning to trial Clean Current Power Systems underwater turbine technology. Along with the MCT turbine, this is due to be installed in 2012. (See lead image for Clean Current device.)

While many of these systems have been tested at various sites before, the marine environment can be a harsh and challenging one. According to one report, during the summer of 2010 the Open Hydro turbine has had to be pulled out of the water a year early after all of its blades broke off in the water.

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 the tidal power is large, theoretically providing up to 2200 TWh of power worldwide, of which the agency estimates around 100 TWh could be economically tapped. While this is not enough to solve the world’s energy problems, in certain key areas it could play an important role in providing baseload renewable energy generation, in much the same way that 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.

Latest indications are that the level of the feed-in tariff will be set in Spring 2011 for devices under 500 kW, with a more comprehensive package of policies introduced in the fall of 2011.

“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,” explained Sandra Farwell.