German ferry operator TT-Line has reported that two of its ro-ro passenger vessels operated on bio-LNG throughout 2025 as part of a collaboration with Everllence PrimeServ Germany.

The vessels, Nils Holgersson and Peter Pan, were commissioned in 2022 and 2023, respectively, and operate in the Baltic Sea on routes linking Germany, Sweden, Poland, and Lithuania. Each of the 230-metre ships is powered by two 8L51/60DF engines and two 6L51/60DF engines.

TT-Line explained that the use of bio-LNG instead of fossil LNG can significantly reduce emissions, noting that replacing one tonne of fossil LNG with bio-LNG can cut approximately 2.75 tonnes of CO₂ emissions.

As part of the collaboration, Everllence carried out continuous emissions monitoring on board Nils Holgersson for nearly a year to support operational optimisation. The measurements indicated no significant ageing effects on the engines related to methane emissions, confirmed that emission levels measured during testing could be reproduced in real operating conditions, and found no negative impact on engine operating parameters during bio-LNG use.

“With the use of climate-neutral bio-LNG, which is obtained from waste materials, TT-Line is making a decisive contribution to climate protection on the Baltic Sea. Thanks to this technology, our Green Ships — the Nils Holgersson and the Peter Pan — enable a CO₂-free journey throughout the entire fleet,” said Andreas Schaerli, COO of TT-Line.

The bio-LNG used by the vessels is produced from agricultural waste in northern Europe. Biogas generated from waste is injected into the gas grid, then extracted, liquefied, and delivered by bunker vessel to ships.

TT-Line also offers passengers the option to add bio-LNG to their booking to offset emissions associated with their journey.

Dr Michael Filous, Senior Vice President and Head of PrimeServ Germany, Everllence, commented: “The key benefit associated with bio-LNG is the reduction in CO₂ emissions. A major advantage for the customer is that while there are specifications that the fuel gas needs to fulfil — such as methane number — no additional engine work is necessary as long as the fuel gas meets the specifications.”

The resulting emissions reductions help lower the company’s fleet emissions in the Baltic Sea through a pooling mechanism supported by certificates issued by the fuel supplier that document the emissions savings achieved compared with conventional fuels.