National Oceanic And Atmospheric Administration- NOAA: U.S. Winter and February Cooler Than AverageNOAA’s State of the Climate report for the winter season (December through February) and the month of February, state that temperatures were below normal for the contiguous United States. The winter season was wetter than normal; however precipitation in February alone was slightly below average. […]
- NOAA’s Fisheries Service and the U.S. Fish and Wildlife Service Propose ESA Listing Changes for the Loggerhead Sea TurtleNOAA’s Fisheries Service and the U.S. Fish and Wildlife Service (FWS), jointly referred to as the Services, announced today their joint determination that the loggerhead sea turtle (Caretta caretta) is globally comprised of nine distinct population segments (DPSs) that qualify as “species” for listing as endangered or threatened under the Endangered Sp […]
- Hurricane Forecasters Bring Preparedness Message to Atlantic, Mexico and CaribbeanNOAA and the U.S. Air Force Reserve will host a series of public events from March 18 to 27 in six coastal communities in Bermuda, Mexico and the Caribbean to urge residents to prepare for the upcoming hurricane season. […]
- NOAA: U.S. Winter and February Cooler Than Average
- Sea Shephard Ocean Protection
- Sea Shepherd Captain Peter Bethune Takes on JapanSea Shepherd Captain Peter Bethune Takes on Japan The Japanese whaling ship Shonan Maru 2 arrived in Tokyo today with the first New Zealand prisoner of war to be transported to Japan as a political prisoner since World War II. As soon as his foot touched Japanese soil, Captain Bethune reestablished himself as a national hero in New Zealand and an internation […]
- Australian Federal Police Return Sea Shepherd’s LogbooksAustralian Federal Police Return Sea Shepherd’s Logbooks No Charges and All Crew are Free to Go Where They Wish On March 11, the Australian Federal police returned the logbooks for the Steve Irwin and the Bob Barker. No arrests have been made following the raid on the two ships based on a request by the Japanese government. Sea Shepherd expects no arrests. […]
- Shepherds Bust the Hump in Santa MonicaShepherds Bust the Hump in Santa Monica The plan to bust the Hump restaurant in Santa Monica was launched months ago when Sea Shepherd Outreach Coordinator Zoli Teglas first told me about a Santa Monica restaurant serving whale meat. I thought he was joking. But it was not a joke, and Zoli set about organizing a sting operation recruiting Charles Hambleton f […]
- Sea Shepherd Captain Peter Bethune Takes on Japan
- Environmental Protection Agency
- A Place I Knew Nothing AboutWe took off with hiking packs, a tent and fins, carrying even fewer plans and expectations; to a place I hardly knew about. The more we discovered that very little was written about our destination, it drew even more appeal. I just couldn’t wait. Over 30 hours after leaving Boston, my adventure companion and I landed [...] […]
- In the Trenches: Moderation for OpenGovI’m a 20 year EPA staffer and Computer Specialist doing much more than computers these days. One of my tasks is to help moderate comments that come in to the EPA’s Open Government discussion forum. I’ve quickly come to realize that moderating comments in the public arena, especially in these sometimes politically-charged times, requires a curious [...] […]
- To Catch Or To Kill (Part 2)Following up on last week’s blog post, I was pleasantly surprised by the number of comments sent in favor of the “catch and release” school when it comes to eliminating rodents. Since my last blog, I’m pleased to report that we have not had any other unwanted visitors of the rodent family. It’s obvious that [...] […]
- A Place I Knew Nothing About
- Environment
- Bust the Hump in Santa MonicaThe plan to bust the Hump restaurant in Santa Monica was launched months ago when Sea Shepherd Outreach Coordinator Zoli Teglas first told me about a Santa Monica restaurant serving whale meat. I thought he was joking. But it was not a joke, and Zoli set about organizing a sting operation recruiting Charles Hambleton from the [...] […]
- Bust the Hump in Santa Monica
Tidal Energy Funding Cut
Washington, DC — The Obama administration has proposed cutting the budget for one of the most promising energy technologies — tidal energy. At a time when earth-friendly energy sources, such as solar, wind and geothermal are getting increased funding, the President plans to cut research for tidal energy.
About Tidal Energy
Ocean Tidal Power
Some of the oldest ocean energy technologies use tidal power. All coastal areas consistently experience two high and two low tides over a period of slightly greater than 24 hours. For those tidal differences to be harnessed into electricity, the difference between high and low tides must be at least five meters, or more than 16 feet. There are only about 40 sites on the Earth with tidal ranges of this magnitude.
Currently, there are no tidal power plants in the United States. However, conditions are good for tidal power generation in both the Pacific Northwest and the Atlantic Northeast regions of the country.
Technologies
Tidal power technologies include the following:
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Barrage or dam
A barrage or dam is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator. Gates and turbines are installed along the dam. When the tides produce an adequate difference in the level of the water on opposite sides of the dam, the gates are opened. The water then flows through the turbines. The turbines turn an electric generator to produce electricity.
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Tidal fence
Tidal fences look like giant turnstiles. They can reach across channels between small islands or across straits between the mainland and an island. The turnstiles spin via tidal currents typical of coastal waters. Some of these currents run at 5–8 knots (5.6–9 miles per hour) and generate as much energy as winds of much higher velocity. Because seawater has a much higher density than air, ocean currents carry significantly more energy than air currents (wind).
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Tidal turbine
Tidal turbines look like wind turbines. They are arrayed underwater in rows, as in some wind farms. The turbines function best where coastal currents run at between 3.6 and 4.9 knots (4 and 5.5 mph). In currents of that speed, a 15-meter (49.2-feet) diameter tidal turbine can generate as much energy as a 60-meter (197-feet) diameter wind turbine. Ideal locations for tidal turbine farms are close to shore in water depths of 20–30 meters (65.5–98.5 feet).
Environmental and Economic Challenges
Tidal power plants that dam estuaries can impede sea life migration, and silt build-ups behind such facilities can impact local ecosystems. Tidal fences may also disturb sea life migration. Newly developed tidal turbines may prove ultimately to be the least environmentally damaging of the tidal power technologies because they don’t block migratory paths.
It doesn’t cost much to operate tidal power plants, but their construction costs are high and lengthen payback periods. As a result, the cost per kilowatt-hour of tidal power is not competitive with conventional fossil fuel power.