Using underwater turbines to power our cities

An underwater version of wind turbines, tidal turbines turn marine currents into electricity, offering a new source of carbon-free and renewable energy with significant potential.

In Twenty Thousand Leagues Under the Sea, Jules Vernes ponders the incredible potential of the oceans and the possibility of using marine resources to produce electricity. Did he ever imagine that, two and a half centuries later, people would be building huge turbines under the sea?
The Tibal turbine SABELLA in Bénodet Crédits : SABELLA / Y.GLADU

The Tibal turbine SABELLA in Bénodet Crédits : SABELLA / Y.GLADU

Tidal turbines – an underwater version of wind turbines – capture marine current energy and convert it into electricity via an alternator. They currently deliver from 20 kW to more than 1 MW of power (as a comparison, the capacity of the latest offshore wind turbines is around 5MW). Several projects are being developed worldwide. The United Kingdom, the European country with the most advanced tidal turbine technology, plans to get its tidal farms up and running from 2015 and is eventually expected to supply 15% to 20% of the country’s current deman.Today, marine energy represents just  0.01% of global electricity production. But that’s about to change. In Europe, it is estimated that marine energy could supply up to 15% of electricity consumed in 2050, generating 300,000 direct jobs. But to successfully operate these farms, we still need to develop new technologies.

Among the many ways of producing electricity, tidal turbines offer several advantages: electricity production can be estimated accurately because, although the power generated by marine currents is intermittent, it is extremely easy to predict. Equivalent-capacity tidal turbines are also smaller than wind turbines, and the output of a tidal turbine is much greater due to the density of water.
Tidal turbines: a promising new source of carbon-free, renewable energy.
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