How to tap energy from the ocean

This year a new book ‘Marine Renewable Energy Handbook’ was published. The book is written by Bernard Multon, university professor at ENS Cachan in France, and based on input from France’s specialists. The book is about the rapidly emerging technologies for exploiting marine renewable energy, including Ocean Thermal Energy. It provides an overview of the technological, environmental and societal aspects and describes the disciplines where there is room for improvement.

Marine Renewable Energy Book
Marine Renewable Energy Book

Reflections on OTEC development

The book reflects on historical and current challenges of OTEC. It describes the dificulty to prove economic viability of larger OTEC plants, and concludes it is not feasible to rely on the strength of the market alone. A more concerted public effort is required to successfully accomplish this task, according to the French specialists. They encourage industrial actors in the field to connect and group into international consortia of energy

producers, industrials and investors, which would accelerate the commercialization process and stimulate governments to define incentive policies.Today’s efforts focussing on building OTEC pilot plants of sufficient size is described as the right thing to do. It’s a way to establish an operational record of net power production and to prove that the economy of scale for large OTEC plants is justified.

The book stresses the importance of carefully monitoring potential impact on the environment and raises questions in relation to the regulatory framework. “Who knows when regulations specific to OTEC will be introduced?”

What’s next?

The book is positive about the contribution of marine energy in the future. In 2030, it’s expected to represent between 5 and 8% of the ‘mix’ of electricity production worldwide. Regarding OTEC’s share in the ‘mix’, the recent take off of OTEC activities is a promising development. The book summarizes some of the recent activities in the OTEC sector, with an emphasis on the activities at DCNS.

DCNS land-based OTEC prototype (© DCNS)
DCNS land-based OTEC prototype (© DCNS)

DCNS, a French naval defence and ship building company, entered into the field of Marine Renewable Energy, and particularly with OTEC in late 2008, and initiated several studies for offshore OTEC plants in French overseas territory (Martinique,Tahiti, La Reunion islands). Beginning of this year DCNS commissioned a land-based OTEC prototype, which is now operating in Saint Pierre, La Reunion, to test and optimize the different components of the cycle. DCNS’s choice is leaning towards an offshore OTEC pilot plant, 10-20 MW in capacity, according to the book.