Tidal Possibilities

Norway has a limited potential at home for tidal power, but is looking to make great strides abroad for its technology. Hydra Tidal has developed the world’s first full-scale floating tidal power plant and has sights set for India. Hammerfest Strøm has cracked the export market with its seabed fixed turbine, which will be used to help power Scottish whiskey plants.

Tidal power exploits the change in sea level from the gravitational pull of the sun and the moon. The energy in tides is harvested either by utilizing the energy between high and low tides or by using the kinetic energy in the tidal currents.

The EU Ocean Energy Association says the global tidal range energy potential is estimated to be about 200 TWh per annum. At present, three tidal barrages operate as commercial power plants, amounting to a worldwide total of 260 MW of installed capacity. The largest in the world is the La Rance Barrage in France, which has a capacity of 240 MW and has been producing 600 GWh per annum since 1966.

Norway has the theoretical potential to produce only about 1-2 TWh, according to the Norwegian Water Resources and Energy Directorate. The largest amount of tidal power resources is believed to be in northern Norway. However, the greater possibilities for Norwegian tidal technology companies such as Hydra Tidal lies in exports, particularly in the UK, Scotland, and India, according to Bjørn Vang, company spokesman.

“The UK has at least ten times greater (potential than Norway),” said Vang. “India is part of Asia and one of the interesting markets. India has clearly indicated that it wants to be at the forefront of the renewables commitment.”

 

World’s Largest Full-Scale Plant
The Harstad-based company recently launched the world’s first full-scale floating tidal power plant Morild II off the coast of Lofoten. Hydra Tidal’s concept is based on a tidal stream generator that makes use of the kinetic energy of moving water to power turbines, much in the same way as a wind turbine.

Opened in November 2010, the prototype has an installed effect of 1.5 MW and unique turbine blades of laminated wood with a diameter of 23 meters. Both of these variables qualify the Morild II to being the world’s largest floating power plant of its kind.

“We know of no comparable floating tidal power plants in the world,” said Eivind Nydal, Hydra Tidal chief executive. “There are smaller scale models that have been installed, but Morild II is a full-scale plant. The largest known turbine diameter of other power plants is 18 metres, and the largest installed power known to us is 1 MW.”

Morild II can be anchored at different depths and is both towable and dockable. It is connected to the local grid in Lofoten and currently in test mode. Hydra Tidal’s Morild concept has advantages over sea bottom solutions when it comes to operational maintenance and deployment. It is easier to operate and remote control the plant. Plus, it can be positioned for maintenance and severe weather. The company currently has plans for the next version Morild III on the drawing board and is applying to the NVE for concessions for tidal areas in Norway.

“Hydra Tidal is a new example of how Norway has broad ambitions on new technologies for renewable energy production,” said Terje Riis- Johansen, Norway’s petroleum and energy minister at the time of the opening. “In Norway we have already built the world’s first full-scale floating wind turbine, the world’s first osmotic power plant, and soon we will build a wind turbine that will be the world’s largest. Now we are also realizing the world’s largest floating tidal power plant in Lofoten.”

 

Hammerfest Strøm’s HS300, a 300kW prototype installed
at 50 meters depth in Kvalsund in Finnmark, Norway.

© Hammerfest Strøm Tidal Turbine Technology

 

World’s First Tidal Power Array
Another breakthrough in tidal power technology is about to happen off the coast of Scotland via the help of another Norwegian company, Hammerfest Strøm. The company recently got the go-ahead to provide HS1000 tidal turbines for the world’s first tidal power array in the Sound of Islay on Scotland’s west coast.

Hammerfest Strøm specializes in the development of tidal stream turbines and the installation of tidal power arrays. It is partly owned by Iberdrola, the parent company of ScottishPower Renewables, which got approval in March by the Scottish government to develop a 10 MW tidal power array in the Sound of Islay.

The plan is to install ten HS1000 turbines, each capable of producing 1 MW of electricity, with the aim of generating enough renewable electricity to power the whole island. One of the first power customers will be a Scottish whiskey plant. A commercial agreement has been signed with Diageo, one of the largest distillers on Islay, to provide electricity from the project to eight distillers and maltings.

The HS1000 device is designed based on a 300kW prototype, which has been installed in Kvalsundet, Norway for the last six years. In 2004, the prototype device was the first in the world to convert kinetic energy in tidal waters to electricity and deliver to the grid. The company is currently constructing the first HS1000 device that will go into waters off Orkney, Scotland later this year.

“The testing of the HS1000 machine in Orkney this year will help us to finalize our timetable for the demonstration project in Islay, but we will begin work on the project in 2012 and plan to have machines installed as early as feasible during the period 2013 to 2015,” said Keith Anderson, ScottishPower Renewables chief executive.