08 November 2010, 13:45 BST
Could Parisians be getting power out of the Seine by next spring? As part of the city’s 2020 Climate Plan, the Mayor’s office wants to raise awareness of all possible sources of renewable energy. So, while no one’s thinking of damming the iconic river for hydro, a call has gone out for proposals to install eight small underwater ‘hydroliennes’, or hydrokinetic turbines, in its flow. Quite what they’d power is still a moot point, though Deputy Mayor Denis Baupin freely admits that “we’re not expecting the moon and the stars” – more likely just a few street lights, sceptics say. The identification of possible sites, under four of the city’s famous bridges, has helped raise the scheme’s profile.
Not unlike mini wind turbines in shape, hydrokinetic turbines need their support structures tethered to the river bed; the water flows through, turning the blades to generate power. The technology is in its infancy, and nobody’s making any money out of it yet, though US company Free Flow Power has ambitions for commercial-scale hydrokinetic river turbines. Its plan for a 1.6GW power scheme involves hundreds of thousands of turbine units at 59 sites in the Mississippi.
The application of similar principles for underwater tidal turbines is becoming a bit more familiar. In the US, tidal power company Verdant has been running a 5MW pilot project in New York City’s East River since 2007, and there are plans to run a similar project beneath the Golden Gate Bridge in San Francisco.
Meanwhile, three students used Cambridge University’s Manufacturing Engineering Design Show this summer to exhibit their FloDrive Turbine, a ‘portable’ device they say would be capable of producing up to 1kW of hydrokinetic power. Deniz Erkan, Li Jiang and Ned Stuart-Smith claim their turbine would work even in a river flowing as slowly as one metre per second. The students are marketing the prototype as best suited to off-grid applications such as home lighting in developing countries, as it requires no special equipment or skills to install. But a year’s work is required to improve the turbine’s efficiency before commercialisation.
Source: Forum For the Future