West Mira first ever rig to receive DNV GL Battery notation

Northern Drilling’s West Mira has become the first rig in operation to be awarded the DNV GL Battery Power class notation.

West Mira; Source: DNV GL
West Mira; Source: DNV GL

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.

To remind, Germany’s Siemens supplied a battery-based energy storage solution to the West Mira under a contract signed back in December 2018.

DNV GL said on Friday that the installation and testing of the energy storage system were completed with close cooperation between 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.

Geir Fuglerud, director of offshore classification at DNV GL, said: “With the Battery Power class notation, we are helping our customers in the offshore industry take advantage of new technologies for safer, more energy-efficient and environmentally friendly operations.

“Hybrid and fully electric battery solutions have already been installed in almost 200 marine vessels globally. We are now seeing offshore rigs stepping up to take advantage of these energy storage systems, with several more rigs soon to follow West Mira.”

DNV GL added that the system would 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.

Henrik Michael Hansen, area director at Seadrill – operator of the West Mira on behalf of Northern Drilling, stated: “By incorporating batteries, we can reduce the runtime of the diesel engines and maintain operations at an optimized combustion level, thereby increasing energy efficiency while lowering emissions. West Mira has now left Bergen and is heading for operations on the Nova field in the North Sea.”

The Battery class notation applies to li-ion batteries of >20 kWh installed onboard DNV GL classed vessels and offshore rigs and builds on DNV GL’s rules for the installation and use of Li-ion batteries.

Seadrill will operate the West Mira during drilling operations on the six Nova field wells. Wintershall contracted the rig for work on Nova in June 2018. Should all options be exercised, West Mira is expected to be contracted to Wintershall until the first quarter of 2022.


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