Marine Current Turbines, Inc.

Marine Current Turbines (MCT) is a UK company founded in 2000 with the idea of developing tidal power in the UK. The company’s first installed turbine was the 300 kW experimental tidal stream turbine in Lynmouth, Devon. In 2008, MCT installed the world’s largest tidal stream turbine in 2008 in Strangford Lough, Northern Ireland.

Technology

MCT turbines function similar to and look identical to standard wind turbines. In fact, the only real difference is that MCT turbines can work in both directions, taking advantage of tidal forces whether the tide is coming or going. The company produces two turbines, one for shallow water and one for deep water.

The SeaFlow turbine is designed for shallow water applications (no more than 30 meters or 98 feet). Each is capable of producing 300 kW of electricity even though the blades rotate at only 15 revolutions per minute.

The SeaGen turbine is considered the largest single turbine in the world with a rating of 1.2 megawatts. The system was successfully tested in December 2008 in Strangford Lough in Northern Ireland. The SeaGen turbine is displayed in the following diagram.

SeaGen was the first full-scale tidal flow power station to be connected to the grid. The array in Strangford Lough has been extensively studied for impact on a number of marine organisms. The company submitted several studies to the Environment and Heritage Service in Northern Ireland before the test installation was granted a five year permit in 2005. Monitoring started in 2004 and is ongoing. The final report, submitted in 2011, listed the following:

• No major impact on marine mammals has been observed.
• A decline in porpoise activity during installation that normalized after construction crews departed.
• Statistical power to determine the impact on grey seals and porpoises is lacking.
• The turbine does not appear to pose any barrier threat to marine mammals, which swim past it regularly.
• Seals do appear to avoid the turbine, having changed their distribution as a result of its installation.
• There is no observable impact on benthic ecology and colonies lost due to installation have re-grown.
• There was no demonstrable effect on tidal flow as measured by Acoustic Doppler Current Profiling (ADCP).
• Though overall numbers of birds remained stable, there was some small-scale displacement of birds in the immediate vicinity of the device.