Eidesvik Offshore was the world’s first company to have an LNG-powered supply vessel and is now the first to replace one engine with batteries. “When dual- fuel engine no. 2 had a failure, we had the choice of either replacing it or installing a battery package. Based on our good experiences with Viking Energy, we decided to install an energy storage system onboard Viking Princess,” says Mr Hjelland.
Silence is golden
The Viking Princess is a complete Wärtsilä product. “When the vessel was built, Wärtsilä delivered the ship design, engines, control systems and switchboard, so it felt natural to select Wärtsilä as the supplier of our battery system as well,” says Mr Hjelland.
Wärtsilä delivered a 600kWh Energy Storage System (ESS) pre-installed in a container. The package included a battery, transformer, frequency converter, control system and switchboard. The battery package has increased the vessel’s maximum power as it can now deliver 1,500kW instant power to the switchboard compared to the engine’s 1,200kW.
For an engine operator, silence is usually a sign that something is wrong. But when running in battery mode, silence is golden. “The batteries respond extremely well to rapid load changes compared to combustion engines, and these changes are quite normal during Dynamic Positioning operation in rough weather,” says Mr Hjelland.
Savings exceed estimates
For Mr Hjelland, the most important benefits are reduced emissions, fuel consumption and maintenance costs. Depending on the operation profile, the fuel savings of the Viking Princess are something between 10–15 per cent, which is significant. “Just as important though, and more unexpected, is the significant reduction in maintenance costs. We are saving three times more on maintenance costs than estimated."
The reason for the reduced maintenance costs is not only the reduced running hours on the engines, but also that they are kept in their preferred load area of 70–90 per cent, which reduces wear and tear. This in turn results in longer maintenance intervals.
"Depending on the operation profile, the emission reductions are around 15–20 per cent, which is a lot. This will make the vessel attractive on the market" concludes Mr Hjelland.