A prototype tidal turbine has started sending electricity to shore from the channel off Fenwick Point, where the currents between the headland and the open sea are among the strongest on this coast. The machine, developed by the Wrenhaven Marine Institute with an engineering firm from Ostbridge, was lowered onto the seabed last month and connected to the grid this week.
Unlike wind turbines, tidal turbines spin in water flowing in and out with the tides, which means their output can be predicted years ahead. The prototype has three blades, each nine metres long, and is rated at 500 kilowatts, enough when running at full power to supply around 400 homes. A cable runs along the seabed to a small substation near the lighthouse.
Project engineer Ravi Desai said the first days had gone smoothly, with the turbine reaching full output on the spring tide over the weekend. "The sea is a harsh place for machinery," he said. "Salt water, debris and the sheer force of the current all take their toll. The point of a prototype is to find out what breaks before we build bigger ones."
Watching the wildlife
Underwater cameras and listening devices have been placed around the turbine to record how seals, porpoises and fish behave near it. The blades turn relatively slowly, at around 12 revolutions a minute, and earlier studies elsewhere have found little evidence of harm, but marine biologist Dr Sigrid Ellefsen said local data was essential before any expansion.
The tide comes in twice a day whatever the weather. That reliability is what makes this worth the effort.
The two-year trial has been funded with €6.2m from a regional energy innovation fund. If it succeeds, the institute hopes to install a small array of larger turbines in the same channel by the end of the decade. Fishing groups have asked to be consulted early on any expansion, as the channel is used by crab and lobster boats from Fenwick Point harbour.