Tidal Energy has a huge potential to provide long term, secure, low cost, supply of electricity. Especially for island coastal communities like Nantucket Island, Massachusetts. The local community has been split on it’s support of a wind farm in Nantucket Sound but appears to be very supportive of a Tidal Energy generation system.
The proposed installation would provide around 4.2 times the amount of energy flowing into Nantucket right now…very exciting!
Below is an article from one of the local papers as well as a number of interesting links and information about the different forms of tidal energy generation. While tidal energy has not has as much attention as solar and wind it has the potential to provide a very substantial piece of the renewable energy solution for energy independence and weaning ourselves from the addiction to fossil fuels.
In-joy,
Bruce
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Nantucket Island’s Planning and Economic Development Commission supports tidal energy project
Nantucket Independent – Peter Brace January 2008
Nantucket’s Planning & Economic Development Commission voted unanimously last week to support Edgartown’s proposed tidal generation project between Muskeget and Martha’s Vineyard.
At its Jan. 3 meeting, the NP&EDC endorsed the permit issued to Edgartown by the Federal Energy Regulatory Commission (FERC) to install tidal generators in Muskeget Channel. Commissioners also supported the University of Massachusetts at Dartmouth’s request for a $5 million grant from the Renewable Energy Trust of the Massachusetts Technology Collaborative to establish a Federal Marine Renewable Energy Center for the East Coast.
Such a center could provide technical assistance to Edgartown for tidal generation projects and all other renewable energy projects proposed for the Outer Continental Shelf, said Planning Director Andrew Vorce.
Generically known as in-stream energy conversion devices, tidal generators are set in channels where tidal currents, ideally, turn the rotors of the generators at three to eight knots or 2.6 to 6.9 miles per hour. These underwater turbines are typically unidirectional, meaning that their rotors can change direction with the tides. They come in a variety of configurations, including short tubes, double-ended funnels, or open rotors anchored to the bottom. Generators in a specific location would be connected to a nearby power grid with submarine cables.
The NP&EDC also voted unanimously at the meeting to direct Blue Wave Strategies of Boston, Mass. to xapply to the Minerals Management Service for a lease of one square mile of ocean south of Tuckernuck Island for the installation of a data collection tower to be used to determine the viability of building an offshore wind farm.
Both actions are in line with the Planning Commission’s and Nantucket’s belief that alternative energy installations are good for the Cape and islands, but not for Nantucket Sound.
“We’re working together with them [Edgartown and UMass Dartmouth],” said Vorce. “The whole idea is this is a collaboration with the two islands on the waters between the two islands. They’re applying to FERC and UMass is applying for a grant.
“Out of that funding would be funding for Edgartown and, hopefully, Nantucket to investigate renewable energy alternatives in this area.”
The grant money referred to would go toward such explorations, but would not cover the costs of tidal generator and wind turbine installations.
A data collection tower for potential wind turbines south of Tuckernuck, said Vorce, could start collecting data on wind speed, gusts, direction, wave heights, barometric pressure and air temperature in about three years.
At its July 2007 meeting, the commission had endorsed a plan for Nantucket, Edgartown and the University of Massachusetts at Dartmouth to jointly file an application with the Federal Energy Regulatory Commission to build tidal generators between the two islands. But the Planning Commission is now focusing on wind turbine-generated power south of Tuckernuck, one of several alternative sites suggested for Cape Wind Associates’ 130-turbine installation that is now proposed for Horseshoe Shoal in Nantucket Sound.
Edgartown filed its preliminary permit application on July 30 with FERC and has since received its permit. Edgartown’s reasoning for doing such a project with UMass-Dartmouth is to secure renewable energy for Edgartown at the cheapest possible rate, rather than one set by one of two private companies – Natural Currents Energy Services and the Oceana Energy Company – already surveying island waters for possible tidal energy generation sites.
Natural Currents Energy Services, LLC, a Highland, N.Y.-based firm is proposing to generate three gigawatts of power by installing tidal energy generators in Nantucket Sound between Nantucket and Chappaquiddick on Martha’s Vineyard. That is about 4.2 times the amount of electricity – around 70 megawatts – flowing to Nantucket right now.
Calling it the Nantucket Tidal Energy Plant, Natural Currents Energy Services is in the preliminary permitting phase of the project that – under ideal review and permitting conditions – would have its tidal generators online by 2011.
The Oceana Energy Company of Washington, D.C. received a preliminary permit from the FERC last summer to test the waters of Vineyard Sound in an area bounded by the southwest end of Naushon Island and extending northeast on both sides of Lucas Shoal and Middle Ground, according to Oceana’s preliminary permit filing with FERC.
Oceana, which is going to be building its own underwater turbines, told the FERC it would install 50 to 100 units with propeller diameters of around 35 feet in water as deep as 75 feet.
Theoretically, Oceana would like to generate 25 to 100 megawatts, with each generator producing 500 kilowatts to two megawatts of electricity, enough
power for about 750 homes.
Article
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News coverage of the worlds most efficient water current turbine, the Davidson-Hill Venturi Turbine
[youtube]http://uk.youtube.com/watch?v=H8ZIXrQcmC4[/youtube]
Gavin Harper of ECOGEEK.com Discusses Tidal Power with attendees of the All Energy Conference in Aberdeen Scotland
[youtube]http://uk.youtube.com/watch?v=d0BY1CBvqRs&feature=related[/youtube]
New Guidelines for Hawaiian Ocean Energy Projects
Nov.2007 -RenewableEnergyAccess.com
OTEC News -Clean Energy, Water and Food
UK energy and power experts meet to discuss the latest developments and initiatives in wave and tidal power technology across Britain.
[youtube]http://ca.youtube.com/watch?v=ZcA3e8_j8XA&NR=1[/youtube]
[youtube]http://ca.youtube.com/watch?v=hR3joMykdRo[/youtube]
Oregon hopes to catch energy wave.
-The Portland Tribune- Anne Distefano, July 24, 2007
“The push to make Oregon a center for ocean wave energy is rapidly gaining.
3 Ways of Using the Tidal Power of the Ocean
There are three basic ways to tap the ocean for its energy. We can use the ocean’s waves, we can use the ocean’s high and low tides, or we can use temperature differences in the water.
1 Wave Energy
Kinetic energy (movement) exists in the moving waves of the ocean. That energy can be used to power a turbine. In this simple example, (illustrated to the right) the wave rises into a chamber. The rising water forces the air out of the chamber. The moving air spins a turbine which can turn a generator.
When the wave goes down, air flows through the turbine and back into the chamber through doors that are normally closed.
This is only one type of wave-energy system. Others actually use the up and down motion of the wave to power a piston that moves up and down inside a cylinder. That piston can also turn a generator.
Most wave-energy systems are very small. But, they can be used to power a warning buoy or a small light house.
2 Tidal Energy
Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant.
In order for this to work well, you need large increases in tides. An increase of at least 16 feet between low tide to high tide is needed. There are only a few places where this tide change occurs around the earth. Some power plants are already operating using this idea. One plant in France makes enough energy from tides to power 240,000 homes.
3 Ocean Thermal Energy Conversion or OTEC
Energy
This is an energy technology that converts solar radiation to electric power. OTEC systems use the ocean’s natural thermal gradient—the fact that the ocean’s layers of water have different temperatures—to drive a power-producing cycle. As long as the temperature between the warm surface water and the cold deep water differs by about 20°C (36°F), an OTEC system can produce a significant amount of power, with little impact on the surrounding environment. The oceans are thus a vast renewable resource, with the potential to help us produce billions of watts of electric power. This potential is estimated to be about 10 13 watts of baseload power generation, according to some experts.
The distinctive feature of OTEC energy systems is that the end products include not only energy in the form of electricity, but several other synergistic products.
Fresh Water
The first by-product is fresh water. A small 1 MW OTEC is capable of producing some 4,500 cubic meters of fresh water per day, enough to supply a population of 20,000 with fresh water. OTEC-produced fresh water compares very favourably with standard desalination plants, in terms of both quality and production costs.
Food
A further by-product is nutrient rich cold water from the deep ocean. The cold “waste” water from the OTEC is utilised in two ways. Primarily the cold water is discharged into large contained ponds, near shore or on land, where the water can be used for multi-species mariculture producing harvest yields which far surpass naturally occurring cold water upwelling zones, just like agriculture on land.
Cooling
The cold water is also available as chilled water for cooling greenhouses, such as the Seawater Greenhouse or for cold bed agriculture. The cold water can also be used for air conditioning systems or more importantly for refrigeration systems, most likely linked with creating cold storage facilities for preserving food. When the cold water has been used it is released to the deep ocean.