Northern Drilling’s West Mira ultradeepwater semisubmersible rig has been awarded the DNV GL battery (power) class notation. The rig has deployed a hybrid power plant using Lithium-ion batteries as spinning reserve in dynamic positioning operations.
Installation and testing of the energy storage system were completed with cooperation between Seadrill and 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%, cutting CO2 emissions by 15% and NOx emissions by 12%. The system will also serve as backup 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 Lithium-ion batteries of more than 20 kWh installed on board DNV GL classed vessels and offshore rigs. 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 dynamic positioning systems.
“Hybrid and fully electric battery solutions have already been installed in almost 200 marine vessels globally,” said Geir Fuglerud, DNV GL director of offshore classification. “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.”
West Mira has left Bergen, Norway, and is heading for operations on the Wintershall Dea-operated Nova Field in the Norwegian North Sea.