There is a tide in the affairs of Alstom

To reinforce its renewable energy portfolio, and establish a presence in what it believes will be a significant energy source of the future, Alstom Hydro has signed a licensing agreement with Clean Current Power Systems Inc. (CCPS), a privately owned Canadian company that has had a demonstration model of its tidal current generator in operation at Race Rocks, British Columbia, for the last two years.

The terms of the agreement include an exclusive worldwide licence for ocean and tidal stream applications for CCPS’s patented technology. The agreement also includes provisions for continued close co-operation between the parties in order to further develop technology, deploy demonstrator units and subsequently position Alstom Hydro as both an equipment and turnkey provider for tidal stream farms. Alstom plans to commercialise its first tidal stream products by 2012.

Commenting on the move, president of Alstom Power Philippe Joubert said: ‘We are very excited about getting involved in this innovative renewable energy technology [which] will enable us to leverage our ... hydro and wind technologies’. He added ‘We will be able to provide an additional renewables solution to our customers ... and we look forward to government backing in order to further develop this new

CO2-free technology.

For CCPS, whose main business is to design and license tidal energy technology for a world market that it estimates at 67 GW, the advantages of the partnership are plain – the considerable resources that one of the world’s premier engineering companies can bring to the development. Alstom views itself as the world’s foremost hydro manufacturer and service provider, with over 400 GW of turbines and generators installed worldwide, representing more than 25% of the total global hydropower installed capacity and covering all sizes of hydropower schemes.

The technology

Clean Current’s proprietary tidal energy technology consists of a horizontal axis ducted turbine with a direct drive variable speed permanent magnet generator. The turbine generator is equally efficient in both directions in order to fully utilise two-way tidal currents. In addition, the equipment that operates below sea level has been designed to minimise outage and maintenance time and expense. The outer duct improves hydraulic efficiency and leads to more robust operations, that is, more tolerant to variations in current directions and turbulence.

Clean Current’s tidal generator is claimed to convert the kinetic energy of tidal currents into electricity with unprecedented efficiency. Features of the technology include a simple design with one moving part, no drive shaft or gearbox, no surface structure, long service life, low capital cost, and minimal environmental disturbance. The duct design of the unit, which has no parts projecting above the surface of the water, ensures that there are no exposed blade tips and provides a large hole in the middle of the unit (about 5 m diameter in commercial scale models) through which fish and sea mammals can pass in the (highly unlikely) event that they are to enter the inlet duct area.

CCPS’s tidal turbine generator was originally installed in about 20 m of water near Race Rocks in 2006. The hydraulic and electrical performance of the TTG were tested using an offline load bank for 2 months. After testing was completed in December 2006, the TTG was connected to the control system that feeds electricity into the project’s battery storage system. Then in October 2008 the generator was re-installed at the Race Rocks Tidal Energy Project to replace 2 diesel generators at Race Rocks Ecological Reserve. Testing has now been completed at tidal currents greater than 7 knots. The project has been supported by EnCana Corporation, Pearson College and Sustainable Development Technology Canada.