The Technical Challenge
EVER MORE SOPHISTICATED TECHNOLOGIES
Marine Renewable Energies (MRE) are energies obtained by harnessing marine resources: currents (stream energy), tides (tidal power), waves and swells (wave energy), heat exchanges (ocean thermal energy conversion), salinity (osmotic energy). To be added to this list is offshore wind energy (anchored or floating turbines), as well as marine biomass.
MRE technologies have been developing at a rapid pace since the onset of the 21st century. The reason why their potential is so important is because they generate a never-ending supply of energy and because oceans cover 71 % of the world's surface.
Amons MREs, two very distinct technologies are available:
It uses winds blowing over the ocean's surface, as there are more regular and more powerful thant the ones blowing over land.
Anchored offshore wind turbines
generate energy in what is at this point in time, the most developed mode, both technically and industrially. Offshore production uses the same principles as onshore production: wind propelled blades are connected to a generator converting mechanical energy into electric power.
But the offshore equipment has been designed to weather the constraints of a marine environment:corrsion, humidity and salinity, difficult weather conditions, etc. Foundations are anchored in the seabed using a number of techniques:
monopile, on jacket, tripod, gravity, etc.
Over these last years, performances by these turbines have gradually improved now reaching a 10MW production capacity per turbine
, therefore reducing their numbers as well as the farm footprint.
Floating offshore wind turbines
are at a more experimental development stage. This turbine model is not attached to the seabed using a foundation but anchored to the seabed via cables, which reduces installation and maintenance cost. This has opened new avenues for the harnessing of energy in marine zones further afield at greater depths.
A number of tidal turbines models
are in the process of being developed. Some involve very novel concepts, e.g. floating stream/tidal turbines or turbines on a vertical axis. Both have been designed in Normandy by start-ups and in shipyards.
The Call for Expression of Interest published by the French Environment and Energy Management Agency (ADEME) in September 2013, has led to the installation of two pilot famrs in the Blanchard Race by 2017/2018. This should allow testing a number of technologies, as well as testing construction, operation and maintenance techniques.
Far from mature, the generation of tidal energy know-how still needs to master a number of tehcnological hurdles and represents a major challenge for all involved in research. In Normandy, laboratories and innovation bodies have become considerably involved in this over the past years. Although North American and North European countries are already of the gema, Normandy research nevertheless holds convincing assets both on the national and on the international scene.