With its dual-fuel LNG engines, the option to run on biogas, and zero-emission batteries supported by extensive use of shore power, the 2021-built ferry ‘Aurora Botnia’ is already notable for its green profile.
Now, Wasaline has asked for Foreship’s help to push forward with the ship’s green transition – this time by evaluating a battery energy storage systems (BESS) extension and e-methanol conversion.
The Super 1A Ice Class rated passenger/freight ferry Aurora Botnia serves the 52 nautical mile ‘Kvarken Link’ route, undertaking 20-24 crossings a week between Vaasa in Finland and Umeå in Sweden – two port cities with strong reputations for environmental responsibility.
Supporting Wasaline through the 2021 delivery at Rauma Marine Construction shipyard, Foreship mobilised over a decade of experience in the BESS use on ships for spinning reserve/blackout prevention, peak load shaving, load response, and zero-emission operations.
With IMO targets for ship emissions tightening, and EU penalties and incentives to accelerate low-carbon fuel uptake from 2025, however, Wasaline asked Foreship to prepare a feasibility study on a possible extension or replacement of Aurora Botnia’s existing BESS earlier this year. The two-part project also foresees an evaluation of the technical impacts and business case for a partial engine conversion from LNG to e-methanol duel-fuel.
Joonatan Haukilehto, Head of New Technologies, Foreship, said: “In a relatively short period, the potential of batteries to offer a bigger contribution to zero-emission ship power has advanced rapidly.”
Foreship’s battery study evaluated 12 different BESS extension possibilities for return on investment and technical complexity.
Haukilehto said: “We based our analysis on the improved energy efficiency of the vessel and the low price of shoreside electricity and factored in the shelter and cost incentives the energy type will offer under EU emissions arrangements.”
Based on complexity, cost, stored energy, power, and regulations, Foreship identified multiple scenarios to replace the existing 2.2MWh BESS with a 6-8 MWh capacity system without major structural or electrical infrastructure work. In addition to evaluating the replacement of the existing BESS with many years of usable life ahead, Foreship evaluated keeping the NMC-type installation as-is, and adding another battery storage space, thus increasing BESS capacity to 10-14 MWh.
Haukilehto added: “With cheap electricity available from shore power not only covering 100% of ship’s power needs during port stays but also charging batteries, the retrofit could contribute up to 20% of overall ship energy needs. Furthermore, the vessel’s total energy efficiency is clearly improved by the possibility to run on a single engine on high load for the majority of voyages.”
Haukilehto considers that the potential engine conversion to run on methanol would be straightforward, given that many of the systems could use the same routing as existing LNG-related systems. While a separate methanol fuel treatment room would need to be factored in, fuel storage space would not be a major factor, given the short voyage involved and a favourable existing tank arrangement.
Image: ‘Aurora Botnia’ (source: Foreship/JLA)
