OSV owners are investing in retrofitting diesel-electric/LNG-powered fleets with battery-hybrid propulsion in a move that is paying off for the charterer, owner and the environment
“We’re known, at least in Norway, as a powerhouse of innovation,” Eidesvik Offshore executive vice president and chief operating officer Jan Lodden told delegates during a session at the Annual Offshore Support Journal Conference, Awards and Exhibition in London in February. “We like to say that innovation is in our DNA,” he said.
Such a statement is well justified given Eidesvik Offshore’s history as a pioneer in the use of liquefied natural gas (LNG) as a fuel in the marine industry, introducing Viking Energy, the first dual-fuel, diesel-electric-powered platform supply vessel (PSV) in the world in 2003. Viking Energy’s diesel-electric plant consists of four Wärtsilä 6L32DF dual-fuel engines, each with an output of 2,010 kW at 720 rpm, driving the main generator sets. It has since been outfitted with batteries, making it one of the few LNG or marine gasoil (MGO), battery-hybrid ‘tri-fuel’ OSVs in the world.
Since the conversion of Viking Energy, Eidesvik Offshore has made further capital investments, and now has five diesel-electric vessels that have been retrofitted with battery-hybrid technology. In 2020, two more PSVs, Viking Neptun and the uniquely shaped PSV Viking Avant, are scheduled to retrofit.
Named ‘Ship of the Year’ at Nor-Shipping in 2004, Viking Avant has a diesel-electric propulsion system supplied by ABB which incorporates four generators, each of 1,825 kW, two compact Azipod propellers, each of 3,000 kw, two frequency converters for the main propulsion and two water-cooled transformers for the main propulsion, each producing 4,000 kVA.
The power station consists of four Caterpillar 3516B diesel engines, each with an output of 1,800 kW. Viking Avant also has a selective catalytic reduction (SCR) system that uses diesel exhaust fluid to reduce NOx emissions from the vessel’s exhaust gases.
Built in 2015, the subsea construction vessel Viking Neptun was fitted with Wärtsilä engines and Wärtsila’s Low Loss Concept electrical systems. By choosing Wärtsilä’s battery hybrid solution, the ship will be able to operate on a single generator set together with batteries during dynamic positioning (DP) operations. Integration of the new battery hybrid system with the existing Wärtsilä control systems will be ‘seamless’, says Wärtsilä.
The Wärtsilä scope includes two 870 kWh battery packs and two 2.7 MW drives for the hybrid system pre-installed in containers. Wärtsilä will also upgrade the existing switchboard, as well as the integrated automation and power management systems.
The seven retrofits represent a total investment of Nrk180M (US$17.9M), of which Nrk66M (US$6.6M) was covered through government and NOx fund support.
In January Eidesvik Offshore made a splash with its announcement of the installation of a fuel-cell project powered by ammonia in Viking Energy. Underpinned by €10M (US$11.1M) in funding from the European Union, the €23M (US$25.6M) project will see a 2 MW fuel cell installed in Viking Energy in 2023 and tested for a 12-month period.
While it started with Viking Energy, it was the company’s third LNG-fuelled PSV, Viking Lady, that was a ‘step change’ for Eidesvik Offshore, says Mr Lodden. Delivered in 2009, Viking Lady was built with a dual-fuel, diesel-electric power plant, comprising four Wärtsilä 6R34DF engines driving generators to provide electric power for propulsion and ship’s systems.
Partnering with DNV GL, Wärtsilä and MTU Onsite Energy in the Norwegian research project FellowSHIP, and supported by Innovation Norway, Eidesvik retrofitted Viking Lady with a 320-kW fuel cell powered by LNG. The molten carbonate fuel cell was removed from Viking Lady in 2015 after five years of testing. Mr Lodden says it “worked as expected”, adding that the company learned it was best suited for ridged power requirements.
In parallel with its fuel-cell project, in 2013 Eidesvik started testing a lithium-ion battery system supplied by Corvus Energy and Wärtsilä, with 350 kWh and 900 kWh in operational capacity of peak shaving and cycling. Viking Queen was fitted with a battery system in 2015. This system had 625 kWh and capacity of 1.6 MWh for peak shaving and a start and stop function.
Viking Energy became the first vessel with a spinning reserve and battery notation from DNV GL in 2016 when it was fitted with a battery system.
In 2017, Mr Lodden says Eidesvik Offshore experienced another ‘step change’ when it fitted Viking Princess with a battery system. The conversion grew out of a generator failure, explains Mr Lodden, “but instead of the replacing the generator, we installed a battery system.” As a result, Mr Lodden says, “Going forward, vessels will be built with a generator and battery system.” He also points out that the battery refits could not have been undertaken without support from its clients. He says Chevron in the UK supported the move to battery-hybrid propulsion for Viking Princess.
Paying off for owner and client
Switching to battery-hybrid propulsion is paying off for both the client and Eidesvik Offshore, says Mr Lodden. The inspection, maintenance and repair (IMR) vessel Seven Viking’s conversion from diesel-electric propulsion to battery-hybrid in 2018 yielded 975 tonnes of fuel savings in the vessel’s first 10 months of operation. The fuel savings benefit the charterer and result in better contracts for Eidesvik.
Battery power has also increased the dynamic positioning capability of the vessel. Mr Lodden ticked off initial results from operations, such as Nrk6.6M (US$655,000) in annual fuel savings and Nrk7.7M (US$760,000) in maintenance savings as a result of 36% to 37% less running hours on the main engines. He estimates the payback time for the battery installation will be about four years.
Mr Lodden says the feedback from the crew has been positive, too, with the general feeling that the battery hybrid propulsion system was more robust, providing an improved power response and allowing the vessel to stay in DP mode longer.
From initial analysis and lessons learned, Mr Lodden expects to see additional fuel savings based on switching from using the vessel’s larger output engine to the lower output engine. “We need to be patient with our crew and we don’t want to push them too hard, too fast on technology,” he notes.
Sharing Eidesvik Offshore’s experience, Mr Lodden offers a few words of advice for others considering retrofitting their offshore vessels with battery-hybrid systems. “You need to calculate enough time for the installation,” he says. “These are complex upgrades. I’ve seen some estimates that they can be done in two weeks. Our experience is three to four weeks to get everything working.” Eidesvik Offshore estimates that payback time is five years and Mr Lodden does not see the price of the retrofits dropping significantly, even if the cost of batteries continues to drop. “They are a small part of the cost,” he notes.
Battery-hybrid propulsion resulted in emissions reductions of about 20%, says Mr Lodden. The seven battery-hybrid conversions in Eidesvik’s fleet are expected to yield 3,020 tonnes of fuel savings annually, equating to 9,070 tonnes of CO2 reductions.
He sees battery-hybrid propulsion as only part of the solution for meeting IMO greenhouse gas (GHG) emission reduction targets of 50% by 2050. “Hybrid represents part of the solution with a new energy source. It is more challenging with a new energy carrier, so the more you can reduce the energy requirements, the better. That is why we are focusing on ammonia.”
Harvey Gulf opts for battery-hybrid retrofits
Eidesvik Offshore is not the only OSV owner convinced of the merits of investing in battery-hybrid upgrades for gas-fuelled PSVs. US-based Harvey Gulf International Marine (HGIM) has begun planning the retrofit of two LNG-fuelled PSVs with containerised battery solutions. HGIM has selected class society ABS to provide technical reviews and survey verifications of vendor-supplied equipment and installation aboard the PSV Harvey Energy.
Built as one of a series of LNG-fueled PSVs, Harvey Energy will be the first to undergo a battery-hybrid retrofit. Power for the PSV is supplied by three Wärtsilä 6L34DF dual-fuel gensets providing 7,530 kW, with fueling provided by Wärtsilä’s LNGPac system.
Wärtsilä’s hybrid solutions are based on a fully integrated hybrid power module that integrates the engines, an energy storage system using batteries, and power electronics optimised to work together through a Wärtsilä-developed energy management system.
ABS is providing guidance for the safe development and deployment of hybrid power. For the Harvey Energy lithium-ion battery integration project, ABS will: review test reports, specifications, and safety features to assess compliance with requisite rules and standards; review structural documentation on battery containers for compliance; witness testing of converters that transform battery voltage to ship system voltage; review technical documentation for structural, electrical, fire suppression, HVAC, safety systems and the testing of system batteries, convertors, transformers, HVAC units; review technical documentation for the installation of a container on board that covers stability calculations, structural and electrical drawings; review any modification of the switchboard drawings for hybrid system; and review the integration with the existing ship systems.
After the retrofit, Harvey Energy is expected to achieve the ABS class notation ESS-LiBATTERY,
The installation of a Wärtsilä 1,450 kW battery-hybrid solution is anticipated to reduce Harvey Energy’s exhaust emissions, fuel consumption, and noise level. The overall fuel cost savings are projected in the range of 10 to 20%, according to HGIM. It is also projected that the battery capacity will be sufficient to sail in and out of harbour on electric power with fewer engines running, while also supplementing hotel load electricity when docked, which will reduce noise and pollution levels in the harbour area. Furthermore, the ability to operate on battery power will assist redundancy during DP operations at the offshore platform.
For the battery-hybrid retrofit of Harvey Energy’s sister vessel, Harvey Champion, GE’s Power Conversion business is supplying its SeaGreen energy storage system to manage energy sources according to load demand, enabling marine operators to optimise energy usage while providing continuity of operations, increased efficiency and reduced emissions.
Included in the transformer-less solution are two 1000A systems, each with batteries, drives and supporting cooling and safety systems, all mounted within a single ISO container.
“Harvey Champion is one of America’s first OSVs that will be equipped with a battery energy storage system, aiming to achieve emissions reduction and fuel-efficiency benefits,” says HGIM chief executive Shane Guidry.