This is an excerpt from EERE Network News, a weekly electronic newsletter.
U.K. Company Reports Successful Tidal Energy Production
The Engineering Business Limited (EB), a company based in the United Kingdom, reported partially successful results from its tidal energy prototype in December. The prototype, called Stingray, was temporarily installed in Scotland's Yell Sound in mid-September 2002, and then retrieved at the end of that month.
According to the December report, the Stingray operators were able to generate a peak hydraulic power of 250 kilowatts and a time-averaged output of 90 kilowatts, with the tidal stream flowing at 1.5 meters per second. Automatic operation achieved a continuous output of 45 kilowatts, although an undersized oil reservoir prevented full-speed operation. However, the company reports hydraulic power rather than true generator power in its report, stating that "power data measured from the hydraulic system was more reliable than the data produced from within the generator/drive system and is the best output performance measure at the moment."
Even using the hydraulic power numbers, the machine fell below its goals, which were to achieve a 150-kilowatt average output in a tidal stream of 2.0 meters per second. The company's subsequent cost estimate for a 5-megawatt demonstration plant yielded power costs between 8 and 30 U.S. cents per kilowatt-hour, which is a wider range and higher cost than predicted by other wave and tidal energy developers.
Still, the company is encouraged by its initial results, and is planning to modify the Stingray machine, redeploying it in Yell Sound this summer. The company will also continue preparations for the proposed 5-megawatt installation, which it hopes to begin installing in summer 2004. See the EB report (PDF 305 KB). Download Acrobat Reader.
Meanwhile, a Norwegian company called Hammerfest Strom AS is working to install its own tidal energy prototype device in Kvalsundet, Norway. The device looks much like an underwater wind turbine. The company has installed the base, the connecting lines, and the shore terminal, and hopes to install the turbine nacelle in January or February. See the Hammerfest Strom Web site.