Estonia's new state workboat powered by biomethane from Saaremaa cattle manure

The Estonian State Fleet (Eesti riigilaevastik) is set to acquire a new workboat powered by biomethane derived from cow manure on Saaremaa Island. The vessel is being completed at the Saaremaa-based Baltic Workboats (BWB) shipyard and represents a significant innovation in both shipbuilding and fuel source.

Local cows now contribute more than milk – manure is transported by tanker trucks from Saaremaa farms to the Tahula biogas plant, where it is converted into usable fuel. Lauri Jasmin, head of the Tahula facility, explained that five loads of manure are required to produce one container of fuel, equivalent to the daily output of one and a half large farms.

The compressed biomethane is delivered to the vessel in containers, with three containers aboard at any time. Project manager Rando Varblane noted that the system is unique because it uses two sets of containers – six in total. Three are always on the vessel, while the other three can be sent to any biogas plant in Estonia for refueling.

Depending on speed, the vessel can travel 300–500 nautical miles on a single gas container. Margus Vanaselja, chairman of BWB's board, stated with 99% certainty that this is a world-first. The vessel uses an internal combustion engine, but instead of diesel, it runs on methane – specifically biomethane. Vanaselja expressed hope that this will not be the only such vessel and that Estonia will continue to innovate.

Captain Ernst Siniorg noted that the fuel type makes little difference to the captain's duties, as long as the vessel has sufficient power. He said there is no operational difference between the new vessel and one powered by fossil fuels. Jasmin joked that the cows are doing a fine job and can 'sail the seas perfectly well'.

Biomethane is produced by purifying raw biogas to nearly natural gas purity. The process breaks down organic waste, in this case agricultural manure, through anaerobic digestion to create biogas, which is then refined by removing carbon dioxide and other impurities.