Alternative Green Energy Source From Tidal Power
Renewable Electricity Generation by Turbines On The Seabed
Nov 2, 2009
A newly developed source of clean energy is soon to be tested on the seabed of the Bay of Fundy, Nova Scotia, Canada. This new alternative renewable electricity resource will generate power from the tides that, in the Bay of Fundy, are the highest in the world.
Tidal Energy Generator
The generator to be installed consists of a large turbine mounted on a steel base. Designed and manufactured by an Irish company, OpenHydro, one of a number corporations developing tidal technology, the 10-metre turbine will be capable of generating 1 megawatt (MW). The project will test the operation of the turbine and its environmental impact.
The generator consists of a ring of turbine blades at the center of which is a large circular aperture. The outer points of the blades are concealed in a housing containing the electrical generator. This design gives fish, seals and other wildlife room to swim through the center and protects them from being injured by the ends of the blades. The blades have been designed to prevent fish from becoming entangled.
The turbine is one of three that will be tested as part of a Fundy Tidal Energy Demonstration Project for environmental assessment organized by the Government of Nova Scotia's Fundy Ocean Research Centre for Energy (FORCE). They will be situated in the Minas Passage and connected by cables to an on-shore facility between Black Rock and West Bay, Nova Scotia. The project has a three-year timeframe, until 2011.
If the test is successful, Nova Scotia Power plans to develop large-scale tidal generator farms to deliver power to the utility.
Renewable Energy From The Sea
This is only one of several tidal-power projects across the world using or planned to use the OpenHydro turbines.
- The first to feed energy on to a utility grid is in the sea at the site of the European Marine Energy Centre (EMEC) off the Orkney Islands, Scotland. It began delivering to the U.K. national grid on May 26, 2008, as verified by EMEC officials.
- Alderney Renewable Energy organization is planning an array of turbines in the tidal waters off the Channel Islands. It is estimated that eventually 3 gigawatts (GW) of power (i.e., 3,000 megawatts) could be produced, enough for 1 million homes.
- A farm of up to 10 turbines planned for the French utility, Electricite de France (EDF), off the coast of Brittany, is expected to start generating in 2011.
- In the U.S., three turbines will be installed in Puget sound, off the State of Washington, as a test for the Snohomish County Public Utility District, the 12th largest utility in the U.S.
Harnessing tidal power is not new. As far back as the 17th century, mills were being driven by tidal water flow. Nova Scotia has been using a system with a dam or barrier since the 1980s. The new technology does away with the need to build a dam or barrier.
Tidal Power Advantages
Tidal power generation has a number of advantages over other forms of 'green' energy.
- It is absolutely predictable and reliable, unlike solar energy and wind power that rely on weather conditions; although recent developments are improving solar power for low light conditions and making wind power more stable.
- The energy density is high; i.e., because water is much more dense than air, a turbine can be much smaller than a wind turbine for the same electrical output.
- The tidal turbines are noiseless. Utility-sized wind turbines, on the other hand, have been blamed for causing low-frequency noise that is irritating to some people, although small wind turbines for industrial and business premises are much quieter.
- The new turbines use no oils or grease for lubrication, hence do not contaminate the environment. They sit on the sea bed at a depth that ensures the structures pose no hazard to shipping and are not visible from land or sea to intrude on a landscape or ocean view. Only a test installation mounted on pylons allowing it to be raised above the surface for inspection, such as at the Orkneys, would be visible.
Green Power for the World
Major tidal streams exist around the coast of every continent, says OpenHydro. If only 0.1% of the energy available from oceans were converted to power, it has been estimated that this would supply more than five times the current global demand for energy, according to the U.K. government's Marine Foresight Panel of the Office of Science and Technology.
The recent test projects, and the delivery of power in the Orkneys, hold the promise of a widespread source of electrical energy, one which does not damage the environment or wildlife nor depend on unreliable sources such as wind and intensity of sunlight.
Sources: OpenHydro, U.K. Marine Foresight Panel of the Office of Science and Technology, Electricite de France (EDF), European Marine Energy Centre, Fundy Ocean Research Centre for Energy (FORCE), Nova Scotia Power, Sustainable Development Technology Canada (SDTC).
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