Northern Drilling's West Mira first rig to receive DNV GL Battery (Power) notation

Northern Drilling’s West Mira is the first rig in operation to be awarded the DNV GL Battery (Power) class notation. West Mira is an ultra-deepwater semi-submersible designed by Moss Maritime, operating a hybrid power plant using Lithium-ion batteries as spinning reserve in dynamic positioning (DP) operations and to supply power during peak load times, the company said in its release.
 
Installation and testing of the energy storage system have been completed with close cooperation between Seadrill/Northern Drilling, Siemens, Kongsberg Maritime and DNV GL. By using the four converter-battery systems, the operator estimates it will be able to reduce the runtime of the rig’s on-platform diesel engines by 42 percent, cutting CO2 emissions by 15 percent and NOx emissions by 12 percent. The system will also serve as back-up to prevent blackout situations and provide power to the thrusters in the unlikely event of loss of all running machinery on affected switchboard segments.
 
The Battery class notation applies to Li-on batteries of >20 kWh installed on board DNV GL classed vessels and offshore rigs and builds on DNV GL’s rules for the installation and use of Li-on batteries. DNV GL has also updated its rules for dynamic positioning to include batteries as a “spinning reserve”, a redundant power source for dynamically positioned vessels designed to fulfil IMO equipment class 2 or 3 for vessels with DP systems.
 
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