Sustainable Energy

Tidal turbine without gearbox built as sector seeks to drive down costs and push innovation

Key Points
  • A number of interesting tidal energy projects are taking shape around the world.
  • The turbine's development has been aided by 2.25 million euros of funding from the European Commission
Nora Carol Photography | Moment | Getty Images

A business in Scotland has completed work on a new turbine which it claims will drive tidal energy costs down by 30% thanks to design modifications.

In an announcement at the end of last week Nova Innovation said that the 100 kilowatt Direct Drive Tidal Turbine, or D2T2, had been built at its manufacturing site in the Scottish capital, Edinburgh.

The turbine's development has been aided by 2.25 million euros (around $2.54 million) of funding from the European Commission and has been tested both onshore and offshore.

One feature of the turbine is that it does not require a gearbox. According to Nova Innovation, having fewer moving parts in the turbine boosts reliability and lengthens the time between service intervals.

The D2T2 is now set to be introduced to Nova Innovation's tidal array in waters off Shetland and a deal has also been struck to send 15 of the turbines to a project in Canada.  

A number of interesting tidal energy projects are taking shape around the world. These include a project in the Faroe Islands focusing on tidal "kite" technology.

Swedish company Minesto's technology takes the concept of flying a kite and transfers it to the ocean to produce electricity. It does this by harnessing underwater current, which creates a "hydrodynamic lift force" on the system's wings, pushing it upward.

An onboard control system and rudder steer the "kite" in a figure-of-eight. As it moves, water flows through the turbine, producing electricity. On Monday, Minesto said that the gravity-based foundation for the scheme, in the Vestmannasund strait, had been installed.  

Elsewhere, a company called Orbital Marine Power is developing a turbine with a 72 meter long "floating superstructure" that's used to support two 1 megawatt (MW) turbines.

While the potential of ocean energy has been touted by its supporters for years, it has a long way to go if it is to compete with other renewable sources of energy, such as wind and solar.

In 2019, just 1.52 MW of tidal stream capacity was added in Europe, according to Ocean Energy Europe. For wave energy, additions were 0.6 MW.

To put these numbers into context, figures from WindEurope show that European countries installed just over 3.6 GW of offshore wind capacity in 2019.

The International Energy Agency (IEA) has said that "electricity generation from marine technologies" grew by an estimated 13% last year.

While this is a positive, the IEA adds that policies which promote research and development "are needed to achieve further cost reductions and large-scale development."