Tidal turbines are part of Siemens' Environmental Portfolio. In fiscal 2011, revenue from the Portfolio totalled about €30 billion. In November 2011 Siemens increased its stake in the company to 45 percent and has now taken it to 90 per cent. Siemens is planning to complete the acquisition of Marine Current Turbines in the coming few weeks. Financial details of the deal have not been disclosed.

Marine Current Turbines has become a technology leader in tidal power systems. The firm has already successfully implemented a commercial-scale demonstration project with SeaGen in Strangford Lough in Northern Ireland. Since November 2008, two axial turbines with a combined capacity of 1.2 megawatts (MW) have been providing power to approximately 1500 households. SeaGen has to date fed more than three gigawatt-hours of electricity into the grid.

In terms of power generation this is the largest tidal current power project to date. Further projects are at the planning stage, including the 8-MW Kyle Rhea project in Scotland and the 10-MW Anglesey Skerries project in Wales.

The SeaGen tidal turbine is fixed on a structure and generates electricity by using tidal current flows. The technology is effectively similar to a wind turbine, with the rotor blades driven not by wind power but by tidal currents. Water has an energy density that is 800 times higher than that of wind. Twin rotors turn with the tidal current and optimally track the direction and speed of flow thanks to blades which can rotate through 180 degrees. A key advantage is that the generated power is precisely predictable in the tidal cycle.

Ted Scheidegger, CEO of the Solar & Hydro Division of Siemens Energy, said:

"The acquisition of Marine Current Turbines is an important step forward for the Solar & Hydro Division."

"We will continue to drive the commercialization of this promising technology which harvest energy from highly predictable tidal streams. Our target is to secure a leading position in this future business."

Global carbon reduction commitments are increasing demand for reliable marine current power, with experts expecting double-digit annual growth rates for the sector up to 2020. The worldwide potential for power generated by tidal power plants is estimated at 800 terawatt-hours (TWh) annually - approximately 25 percent more than the total power demand of Germany and equivalent to between three and four percent of global power consumption. Coastal regions with strong tidal currents like those in the UK, Canada, France and East Asia offer major potential for the utilization of the technology.