GreenPilot – guiding the way to low-emission and fossil-free operation of small vessels

The GreenPilot project converted a pilot boat to operate on renewable methanol fuel, demonstrating the improvements to environmental and operational performance that can be achieved for this fuel. Methanol is a clean-burning alcohol that does not contain sulphur and results in low emissions of particulates and nitrogen oxides when combusted. It can be produced from many renewable feedstocks, which means that “well to wake” greenhouse gas emissions can be significantly lower than those of fossil fuels.

Reducing emissions to meet climate goals

The developing climate crisis has led to the establishment of targets both internationally and nationally to reduce emissions of greenhouse gases. The International Maritime Organization (IMO) adopted a strategy in 2018 that calls for greenhouse gas (GHG) emissions from shipping to be reduced by at least 50 percent by 2050 (compared to 2008 levels).

In Sweden, the government has set an ambitious goal of net zero emissions by 2045, and this is shared by the Swedish Transport Administration’s road ferries. Swedish transport emissions should be reduced by 70 percent by 2030. The Swedish Maritime Administration, another partner in the GreenPilot project consortium, has a vision for a zero-emission pilot boat, and this was a starting point for the project.

Why methanol?

Methanol is a liquid fuel that can be easily stored and bunkered on smaller vessels and it can be produced from many renewable feedstocks. 

It has been used successfully on a few large vessels, including the Stena Germanica, where it demonstrated good performance in a dual-fuel medium speed engine application. Although there are currently no commercially available small marine engines (300 – 1,200 kW power range) that are approved for operation on methanol, development and testing of different methanol concepts for engines in this range were carried out in the SUMMETH (Sustainable Marine Methanol) project, which included many of the same partners as GreenPilot. 

The GreenPilot project was the first to test methanol on board a smaller vessel with a high-speed engine.

Converting a pilot boat to methanol operation

The two-year GreenPilot project began in 2016, with a main goal of converting a 12.6-metre long pilot boat that was made available to the project by the Swedish Maritime Administration. 

The conversion work involved adapting on-board systems, primarily fuel supply and safety, and replacing one of the vessel’s two main engines with an engine converted to methanol operation. Two engines, a Weichai and a Scania SI, were converted by project partner ScandiNAOS to run on methanol using spark-ignited port injection technology. Both engines were tested on land and on the pilot boat.

A compression ignition engine was also tested on land during the later stages of the project and was tested post-project in the pilot boat.

Testing on board

Renewable, fossil-free methanol produced from pulp mill black liquor in a Swedish pilot plant was used in many of the tests. Engine efficiency was tested under real driving conditions, and emissions were measured both in lab testing and on board the vessel.

Diesel-like performance was observed during the testing, with high efficiencies ranging from 37–40 percent. Emissions measurements taken on board included nitrogen oxides (NOx), particulate matter (PM) and particulate number (PN) taken by Chalmers University. SOx was measured during laboratory testing. PM emissions were extremely low, as alcohol fuels do not form soot. NOx formation was reduced as compared to MGO operation, and the emissions from methanol combustion complied with existing and upcoming IMO and EU (Inland Waterway Euro V) regulations.

Emissions from methanol combustion as compared to MGO baseline. MGO shown as 100%. Note that the emissions values are per MJ of fuel. Particulate matter (PM) emissions are shown as mg.

Good environmental performance with renewable methanol

Environmental performance assessment was focused on comparing air emissions on a fuel life cycle basis. The fuel life cycle comparison included emissions both from fuel production, “well to tank”, and fuel combustion on board, “tank to propeller”. Greenhouse gas emissions (GHG) reductions over the fuel life cycle in the range of 94 percent were achieved for methanol produced from pulp mill black liquor (the bio-methanol used in the testing).

Comparison of greenhouse gas emissions for the annual pilot boat fleet operation using marine gas oil (MGO) and methanol produced via pulp mill black liquor gasification (BLG).

Interest in methanol fuel continues to grow

During 2019, more large vessels operating on methanol have entered regular service. Waterfront Shipping added four more dual-fuel methanol tankers to its existing fleet of seven that came into service in 2016. In October, Stena Bulk and Proman announced plans for a joint venture to own and operate methanol-fuelled tankers.

In the smaller vessel segment, significant interest exists but there are no vessels in regular operation. The Port of Antwerp carried out a feasibility study on converting a tugboat to methanol operation and visited the GreenPilot boat in October 2019.

The Inland Waterways Authority of India has announced plans to build methanol-fuelled boats and cargo vessels to reduce emissions and use a nationally produced fuel – methanol made from fossil feedstocks and from municipal solid waste.

ScandiNAOS has continued testing a compression ignition concept engine on the GreenPilot test boat and has tested both methanol and ethanol fuel in the same engine. Both alcohol fuels performed well.

The GreenPilot project showed that it is feasible to convert small vessels to methanol operation. The demonstration of bio-methanol as a low emission, low environmental impact fuel on a pilot boat was a great initiative for this vessel segment.

SSPA is committed to developing sustainable solutions for shipping and was proud to be part of the GreenPilot project team.

The GreenPilot project consortium consisted of the Swedish Maritime Technology Forum at RISE, ScandiNAOS, SSPA Sweden, Swedish Transport Administration, and the Swedish Maritime Administration. The project was co-funded by the Swedish Transport Administration, the Swedish Maritime Administration, and the Methanol Institute.


The GreenPilot project showed that it is feasible to convert small vessels to methanol operation. Photo: ScandiNAOS.

Mr Freddy Debue and Mr Louis Vervloet from the Port of Antwerp visiting the GreenPilot boat in October 2019. Photo: Joanne Ellis.