DCNS Ocean Thermal Energy Conversion NEMO Project

Contracted by MMT AB to provide specialist multibeam personnel onboard the MV Stril Explorer for the DCNS Ocean Thermal Energy Conversion NEMO (New Energy for Martinique and Overseas) project. NEMO is an OTEC project off the west coast of Martinique in the Caribbean Sea. The intention is for a moored barge to be installed housing four turbo-generators. Each will be driven by an ammonia closed Rankine cycle utilising the 20°C temperature difference between the cold seawater at 1.1 km depth and the warm surface waters, with the cold water pumped via a single large diameter riser. Each turbine will produce roughly 4 megawatts, resulting in a total nominal installed capacity of 16 megawatts. The net generated power is to be exported to the local grid via a subsea cable and a substation at an existing conventional fossil fuel power plant. To develop the project DCNS needs to characterize the geophysical context of the area of the offshore power plant and of potential cable routes to the coast. The data will also be used to help in better understanding geo-hazards in the project area and in specifying future geotechnical investigations. High-resolution bathymetry surveys are being conducted using an ROV mounted R2Sonic dual 2024 system. The EIVA software suite is being used for data acquisition and processing, with the ROVINS positioning data post-processed using iXSea’s Delph INS software to improve accuracy. NaviModel is being used for cleaning, surface generation, data visualization and product generation.