Tidal power systems have been under investigation for many years. The earliest method to generate power was with ‘barrage’ systems, which required the construction of dams across inlets and bays. Gates in the dams allowed the basin to fill during high tide, then the gates would be closed, and the basin would be allowed to drain out through turbines to generate power. However, the environmental impacts of these systems, along with the cost and the relative inefficiency, have kept them from much further development. There are some ‘barrage’ installations still in operation in Canada and in France, but no new projects are planned.
Instead, tidal power is being pursued as basically the same way wind power has been developed, turbines. In-line tidal power is intriguing because it is much more regular and predictable than wind, which can be intermittent and is much more dependent on local weather. Water also has a much higher energy density than air does, which makes tidal systems appealing because a water turbine can be smaller than an air turbine.
A tidal power system comprised of six 35-kilowatt turbines has been installed in the East River near Roosevelt Island, New York. This study system is meant to determine the best configuration for the equipment, and help develop easily mass-producible versions of the turbines. A final configuration of 100 turbines is anticipated at this location.
Preliminary site approvals for in-stream turbine farms have already been given for 25 sites along the Atlantic and Pacific coasts of the US, and a further 31 sites are under consideration. Other companies are developing other forms of tidal turbines, some with as much as 1 megawatt capacity.
Previously on EcoGeek
via: MIT Technology Review