1999/02/01 Susaeta, Tomasa Iturria: Elhuyar aldizkaria
The British company IT Power, specialized in alternative energies, is working on a project to build and submerge an electric power generator from the energy of the tides. The Seaflow project is not intended to build an experimental generator, but a fully commercial generator connected to the power grid. The systems used so far to take advantage of tidal energy use the water level difference between low tide and low tide, but the turbines are in the dikes, not at the bottom of the sea. That's why the Seaflow project is completely new.
The current turbine that is desired to be installed under the sea is similar to that of wind turbines, but the rotor is completely submerged to use the tide energy. The first prototype, which is intended to be implemented this same year, will have a power of 300 kilowatts, enough to meet the electricity needs of a small town. It will be implemented on the UK coast, but they have not yet decided where to do it. The main component of the turbine is the submarine rotor: It will have an approximate diameter of 15 meters and will be designed for 12.5 revolutions per minute by the current of 2 or 3 meters per second. The turbine will be placed on a steel column supported on the submarine floor.
If the result of the first prototype is successful, the next step will be the construction of an underwater "tidal power plant", for which we would have to unite between 10 and 20 turbines and achieve between all a power of 2 to 5 megawatts. This power would be sufficient to supply electricity to a population of 5,000 inhabitants. And its installation is scheduled for 2005.
The plant will be almost completely submerged. According to the project promoters, the environmental impact will be almost less than that of the wind power plants, since a mast will leave out of the water to indicate to the ships the location of the power plant. So far no such project has been carried out, as it was clear that the cost of electric energy would be much higher than that of conventional fossil energies. But the same happened with wind power, until technological progress has allowed wind power plants to be economically profitable.
In addition, since about 20 years ago oil was discovered under the North Sea, the technology to work in the marine environment has been very developed and new technologies in oil platforms and the latest technology in wind power plants can be used to build underwater turbines. So what 15 years ago was a dream today can be a reality. The developers estimate that the cost of the resulting electricity will be $0.10 per kilowatt hour. This is even more expensive than what is achieved with the use of conventional energy sources (coal, gas), but as technology improves and evolves, fire promoters expect the price to decrease.
The project has a budget of 360 million pesetas, half of which will be covered with the support of the European Union. The project is entirely European and the British company IT Power collaborates with members from Sweden and Germany.