Two fair-sized tidal energy projects are on their way to the east coast. First up is (ready for this mouthful?) the Edgartown-Nantucket Tidal Energy Plant Water Power Project. The project proposes 50 underwater turbines turned by the ebb and flow of the tide. A 3 mile-long transmission line would carry the electricity generated to land, where it would be sold to local utilities. Edgartown and Nantucket would be the beneficiaries of the 2 MW of peak output.
The second project is planned for Vineyard Sound and it has a slightly more manageable title: The Cape and Islands Tidal Energy Project. This project is looking at clusters of underwater turbines – each with the ability to put out between 1 and 3 MW during peak tide – with up to 150 of these energy generators installed. The proposed turbines are on the scale of what was recently installed off Ireland, which is a 1.2 MW turbine and touted as the world’s largest.
Right now the projects are doing research to see if this kind of output is possible, and if it can be done cheaply enough to make it viable. From what they can tell, the 1.5 meters-per-second average current speed probably won’t hack it to turn the turbines fast enough for them to create enough electricity to make the project worth while. It takes a current speed of about 2 meters-per-second to get that kind of energy generation going. Locals, and EcoGeeks, are eagerly awaiting more test results to find out if these projects could work.
Via CapeCodOnline, MVTimes
A new green project called Honolulu Seawater Air Conditioning (HSWAC) proposes to cool down buildings with seawater, rather than fossil fuel-based air conditioning units, and it is getting some serious green to back it. Private investors have put up nearly $11 M, completing the funding effort for the $152 M project, with about half of the final funding coming from investors from Honolulu. Construction on the project is set to start the first week of January, 2009.
The system will pump cool water, about 45° F, from 1,600 feet below the ocean waves. The water will travel through the pump system to an onshore station where it will cool fresh water that circulates in a closed loop through customers’ buildings in downtown Honolulu. Once the cold seawater has done its job, it is pumped back into the ocean at a shallower level, going through a diffuser to ensure proper mixing and dilution to the surrounding sea. I’m curious as to the maintenance requirements of this system during and after storms, though apparently the creators know what they’re doing since the VP of Engineering at HSWAC and the President of the project’s management company, Renewable Energy Innovations, LLC, pioneered the system in Sweden and have shown that it works quite well.
I’m also curious as to what fuel is going to be used to power the system. Hopefully they’ll take a hint from the newly required solar-powered water heaters and go renewable with the system. Regardless, the savings potential is astounding. Honolulu depends on imported oil and fossil fuels for 90% of its electricity, so to use seawater instead would drop costs by over 20%. Building owners are pretty peppy about this savings, and the project has already committed over half of its 25,000 ton capacity to future customers who have signed on, which even includes the Hawaiian Electric Company’s headquarters. It's a very good sign that there is so much enthusiasm behind the project from businesses and government.
Via TreeHugger, Renewable Energy World; Photo via lrargerich
Shark fins, kelp and whales have already been mimicked for tidal and wind power generation, and now anacondas get their time in the spotlight. Francis Farley, an experimental physicist, teamed up with Rod Rainey of Atkins Oil and Gas to invent a new device that harnesses wave power, but is made of inexpensive materials and is easy to maintain. They have named it the Anaconda because of the snake-like look.
The distensible rubber tube is closed at both ends and filled with water. One end faces the oncoming waves where the wave squeezes it and creates a bulge wave inside the tube. Bulge waves head down the tube, with the outside water accompanying it, pushing it along and causing the bulge wave to grow. Finally, the bulge wave flows past a turbine where energy is generated and fed to shore through a cable.
While only a prototype has been created so far, the inventors are getting back up from the University of Southampton, where lab experiments and studies will help the Anaconda scale up and become a reality. And by scale up, we mean big-time scale up. A fully grown Anaconda would be nearly 700 feet long and 23 feet in diameter, and would gather power from oceanic depths of 130 to 330 feet. But the size is equivalent to its output. One unit could produce 1 megawatt. That’s a lot of power from a big snake. And because the goal is to keep it cheap and easy to maintain, the hope is that the cost of electricity from the snake would only be $0.12 per kWh – a competitive price. Still, it will be about 5 years of testing before we see if the Anaconda pans out. See the Anaconda swim here.
Via Treehugger, University of Southampton, GreenCarCongress
There have been a lot of new designs for systems that can harness power from the waves, tides, and currents flowing in our oceans, but a new concept, currently in the testing phase, struck me as unique. BioPower Systems, based in Sydney, is developing systems to capture energy from both wave and tides, and currently has two products in ocean-based pilot projects, the bioWAVE and the bioSTREAM.
The wave power system, bioWAVE, was inspired by the swaying motion of sea plants, like kelp, as waves rolled over them. The device, which is anchored to the ocean floor, has buoyant “blades” which move upward and downward with the flow of waves. What was particularly interesting was that in rough conditions, the system will automatically lie flat against the bottom, preventing or at least minimizing damage.
The bioSTREAM, in contrast to its brother, uses the principle of Thunniform, the main method of locomotion of large fish, commonly seen as the side to side motion of the tail. The system, however, uses the principle in reverse. Instead of being propelled forward, the anchored generator turns the tail fin from one side to another, capturing the flowing water on its surface, pushing the “tail” section, the resisting torque of which produces electricity to be fed back to land. Once again, due to its streamlined design, it can align itself with current flows, avoiding damage and overloads during extreme conditions.
Both systems, though in the pilot project stage, are eventually expected to come in models that will produce 250kW, 500kW, and 1000kW, matching the specific conditions in any given area.
They’ve got some great animations of the bioWAVE and bioSTREAM that are worth checking out.