Fishing for Energy Efficiency under and over the Sea
Jan 15, 2015
Peter Oram

It may sound like something out of a Jules Verne novel, but harvesting the sea for energy is anything but fiction. From underwater power plants to giant offshore wind turbines, the ocean as a key future energy resource is no longer simply the musings of a 19th century writer. It’s an unrealized story rich in technology and innovation that may well become a fundamental chapter of the planet’s energy future.

Spinning with the tides, dancing with aquatic life, tidal turbines are at the heart of harnessing the ocean’s great power potential which is estimated at up to 100 gigawatts. Regardless of a high initial cost, they provide cost effective, reliable, efficient and clean energy.

With a propeller design similar to that of a wind turbine, a tidal turbine runs at an efficiency rate of between 25-35%. That’s not bad, but it leaves room for significant improvement. Exeter University has developed the MRev Estuarine Turbine, a 3-dimensional device with a much greater surface area for tidal energy extraction. This new design achieves minimum efficiencies in laboratory test of around 55%.

The recently reported £1bn plan to build the world's first power-generating tidal lagoon opens a new promising way to harness the power of tides. Tidal lagoon application converts tidal energy by forcing water through hydro-turbines, activated by a difference in the level of water on each side of the lagoon as the tide rises and falls predictably twice a day, every day. Once completed, the Tidal Lagoon plant will provide sufficient power for the running of 155,000 homes for 120 years!

And the even better news is that energy can be harvested not only from beneath the waters, but from above them, too.

The potential for offshore wind is enormous.  Indeed, it could meet Europe’s energy demand seven times over, and the United States’ energy demand quadrupled.

Thanks to leaps and bounds in technology development, offshore wind power is becoming ever more viable.  In terms of capacity, the turbines of yesterday are dwarfed by those being designed for the offshore market today. Just take for example the HaliadeTM 150-6MW wind turbine, which has a 15% higher yield than that of same-generation wind turbines. A single turbine has a power rating of 6MW, equivalent to powering 5,000 households per annum. Turbines with greater capacity require fewer foundations and inter-array cables, making them more cost-effective and efficient.

Moreover, strong data analytics capabilities, according to GE’s estimates, will allow wind farm operators to raise output by up to an additional 5 per cent through the optimization of performance based on environmental conditions.

Innovation coupled with strong efforts to make offshore wind power more cost competitive is changing the industry. It is estimated that through the implementation of an alternative, creative approach, costs can be reduced by 12%, setting a solid foundation for offshore wind to become a clean and secure energy resource.

Today, technology that was once only imagined in science fiction is becoming reality. Whether it be under the waves or above the water, innovation is following the current of the tides and the wind.

Peter Oram

Peter Oram leads the Renewables Sales function.  Peter has over 20 years’ experience with the company working in roles of increasing responsibility, including Field Engineering Services, Engineering, Project Management, Engineering Director, Business Director and more recently as the Global Sales Leader role for the entire Renewables portfolio since 2013.  Peter is the 2014 Electrifying Change winner for ‘External Focus’ at GE. He graduated from the University of York, and after several global roles, Peter now resides in Rugby, UK.