People tend to think that in order to exploit hydropower, water needs to be confined in closed reservoirs, like high in the mountains or hermetically sealed dams in rivers. But according to some, it does not need to be and ‘leaking’ can be tolerated. In many coastal areas in the world oscillating tidal waves runs parallel to the coast. The idea is to build long dams perpendicular to the coast into the sea. These dams could be used to place windturbines on them, exploiting higher than average wind speeds in coastal regions, but the real innovation is to additionally have turbines placed under the water level, exploiting the energy contained in rising tides. China, Korea or the UK could be suitable candidates to try this idea out, where head differences of a few meter can be achieved. A single dam could generate up to an astounding 15 GW in a predictable way. Potential for China: 80-150 GW. Additional economic advantages could be realized by connecting islands or the constructions of safer LNG ports, far from inhabited areas. All necessary technologies do exist, the challenge though is that small scale demonstration projects simply will not work. In other words: kicking this technology off involves high risks. Power generation capacity increases as the square of the dam length increases (both head and volume increase in a more or less linear manner for increased dam length, resulting in a quadratic increase in power generation).
An offshore turbine is finally spinning in the United States. This marks the first time that any offshore power generation facility has fed electricity back to a utility grid in the United States. Location: Cobscook Bay, part of the bigger Bay of Fundy, off the Maine coast. The TidGen has a peak power output of 180 kilowatts. The company plans on installing another two turbines in the same location in the fall of 2013. End target, possibly 5 MW. The TidGen device, installed in water depths of 15 to 30 meters, takes advantage of water flowing in and out of the bay as the tides change. The Bay of Fundy as a whole is an enormous tidal power resource; ORPC says that 100 billion tons of water flow in and out of the bay every day, with tidal ranges as high as 15 meters. Combined, wave and tidal power have fairly massive potential, up to as much as 15 percent of the U.S. electricity demand according to reports from the Department of Energy.
Ocean Power Technologies, Inc… today announced the successful completion of extensive factory acceptance testing of the first of its next generation power take-off (“PTO”) units for the Company’s utility-scale PowerBuoy®, the PB150. The PTO has now been shipped from OPT’s facility in Pennington, New Jersey to Oregon Iron Works, where it is in the process of being integrated into the spar of the buoy in preparation for deployment off the coast of Reedsport, Oregon. The new direct drive system is a much larger version of that which was recently utilized in the Company’s PowerBuoy deployed off Oahu, Hawaii, for two years in a project with the US Navy.
Water has 1000 times the density of air. This means that with equal flow and rotor area the generated power for water turbines is 1000 times higher than for wind turbines. There is a lot of potential for power generation in the stormy waters that surround the British Isles. We predict that Britain once might rule the waves again. This time not with an imperial fleet in an unsatiable quest for new imperial territory (25% of the planet in 1920), but rather scraping the last few hundreds of megawatts from the bottom of the energy barrel.