Damen Shipyards may adapt tugs to run on methanol. The Dutch shipbuilder received the necessary permission to do so this week. An important step towards sustainability, says Damen.

They are tugs of the ASD Tug 2713 Fuel Flexible type. They are mainly intended for work in ports and along the coast. The 27-metre-long vessels currently run on diesel, although they can also run on HVO, a fossil-free diesel variant produced from residual streams.

The real sustainability hit is expected from the switch to methanol as fuel. Methanol has the advantage of being liquid at room temperature and therefore easy to store. If methanol is obtained from renewable sources, it can reduceCO2 emissions from shipping by up to 95 per cent. Ultimately, it could thus help the industry meet European sustainability targets. In doing so, methanol has a relatively high energy density and, moreover, no completely new infrastructure is available for it.

As methanol can be produced both from fossil sources and sustainably, large-scale production is possible. According to Damen, this guarantees security of supply and excessive fluctuations in prices are not to be expected.

Risk analysis

The Fuel Flexible tugs are already equipped with methanol tanks as standard, but to really run on methanol, more installations are needed. Space had already been set aside for this, but certification was awaited. Because the current safety rules for methanol are written mainly for large ships, such as chemical tankers, and not for smaller vessels like tugs, this was a lengthy process.

Classification society Bureau Veritas and the Environment and Transport Inspectorate, responsible for supervision of Dutch-flagged ships on behalf of the Dutch flag state, jointly conducted a comprehensive risk analysis to investigate how methanol could be safely applied to compact ships.

From this, a series of additional safety measures were rolled out, although Damen is keeping quiet about which ones exactly. Methanol has a different ignition temperature than diesel and additional ventilation measures are also required. Because of the lower energy density, fuel tanks need to be about twice the size of a diesel ship.

Alternative fuels

'This is an important step for our Fuel Flexible tugs,' says Pieter Spruijt, who is responsible for alternative fuels at Damen. 'The approval shows that the design we already received preliminary approval for in 2023 is now actually applicable to several tug models within our fleet. That makes it easier to get other models approved as well.'

According to Herman Spilker of Veritas, the use of methanol as fuel certainly has a future even for small vessels. 'We expect more and more operators to look for alternative fuels, making methanol interesting for compact vessels as well.'

Ultimately, it is up to ship operators themselves if and when they renounce diesel and switch to a more sustainable alternative.

Image: Damen