More sustainable offshore oil and gas development underpins increasing use of battery-hybrid propulsion
Oil companies are taking a more sustainable approach to developing oil and gas resources as they come under increasing pressure from regulators and shareholders to reduce greenhouse gas emissions. As a result, charterers are more closely scrutinising the CO2 emissions from their logistics supply chains and vessel operations.
In response, OSV owners are increasingly turning to battery-hybrid propulsion as a means to cut CO2 emissions and improve fuel consumption. One of the main benefits of battery-hybrid propulsion is the ability to optimise the loading of the prime movers for the generators to obtain maximum efficiency and reduce fuel consumption. This is especially beneficial for OSVs which have a typical operational profile that is divided between transit and dynamic positioning station-keeping operations.
In recent months, battery-hybrid propulsion solutions have begun to gain traction among OSV owners. Norway’s Eidesvik Offshore was awarded a three-year contract by Equinor, extending the charter for 92-m Viking Avant in a deal that underpins the installation of battery-hybrid technology for the vessel, the sixth Eidesvik vessel to be fitted with such a solution. In recent months, Tidewater, Atlantic Offshore and Harvey Gulf International Marine have all announced battery-hybrid propulsion upgrade programmes for vessels.
Overall, of the 377 vessels of all types in operation, under construction or currently on order that will have batteries installed, a total of 63 – almost 17% – are OSVs or other types of offshore vessels, according to class society DNV GL.
US-based SEACOR Marine is aiming to have the largest fleet of battery-hybrid-powered OSVs. Through Seacosco Offshore, its joint venture with China’s COSCO Shipping, SEACOR Marine will add eight battery-hybrid-powered platform supply vessels (PSV), five of which were delivered in 2019. In January 2019, Seacosco Offshore took delivery of the UT 771 WP design battery-hybrid-powered Seacosco Congo, the first such vessel built in Asia. Seacosco Congo, along with its sister vessels Seacosco Paranà, Seacosco Amazon, Seacosco Nile, and Seacosco Murray were all built by China’s COSCO Shipping Heavy Industry (Guangdong).
Each PSV has an overall length of 85.7 m, beam of 18 m, depth of 7.8 m, and loaded draught of 6.5 m, with a clear deck area of 840 m2 and accommodation for 50.
Propulsion power for each diesel-electric vessel is supplied by two MTU 12V4000M33S diesel engines and two MTU 8V4000M33S diesel engines, with two 1,480 kW and two 990 kW Leroy Somer generators. Total installed power is 4,940 kW. Propulsion is supplied by two 1,600-kW Rolls-Royce Azipull fixed-pitch thrusters, one 790-kW Rolls-Royce TT2000 tunnel thruster and one 725-kW Rolls-Royce Combi TCNC.
Fitted in a container located behind each PSV’s superstructure, the battery storage system was jointly developed by Rolls-Royce Marine (now part of Kongsberg) and Corvus Energy. The battery containers were surveyed and tested as complete units prior to shipment for installation on the vessels. In a pilot project, DNV GL issued product certificates for the complete containers, which includes the structure with fire insulation, certified components like batteries, chargers and transformers, electrical installations in the container and testing of the complete container as a component. This reduced onboard testing and allowed for a shorter commissioning time.
SEACOR Marine estimates Seacosco Congo uses 463 litres/hr in cruising mode, 258 litres/hr in economical mode, 367.5 litres/hr in DP mode, 215.8 litres/hr in standy DP mode, and 87.8 litres/hr in port. It has a maximum speed of 13.5 knots, cruising speed of 10.3 knots and economical speed of 8.6 knots.
Built to DNV GL class, the Marshall Islands-flag PSV has DNV GL class notations ✠1A1, SF, EO, Offshore Service Vessel, DK+, HL(2.8), Clean Design, LFL(*). COMFV(3)C(3), Naut OSV(A), Dynpos AUTR, Fire Fighter 1, SPS, BWM-T, BIS, Battery Power.
SEACOR Marine also acquired three UT 771 CD design PSVs, SEACOR Alps, delivered in 2019, SEACOR Andes and SEACOR Atlas, both set for delivery in H1 2020. All three DP2 class PSVs can be upgraded to battery-hybrid power solutions.
SEACOR Marine also has four 87.1-m battery-hybrid PSVs, SEACOR Azteca, SEACOR Maya, SEACOR Viking and SEACOR Warrior, that fly the Mexican flag under its joint venture MexMar.