Methanol as an alternative fuel for smaller vessels

Low emissions with methanol

Methanol is a sulphur-free and clean-burning alcohol that produces very low particulate emissions when combusted. Emissions of nitrogen oxides are also lower than for conventional fuels, with amounts depending on combustion concept and temperature. Although shipping is considered one of the “greenest” modes of transport, it is still a significant source of SOx, NOx, and particulate emissions, which have impacts on human health and the environment. 

Smaller vessels often operate on coastal and inland waterways close to populated areas, and have an impact on air quality in these areas. Emission-reduction solutions for these vessels mostly involve switching to a cleaner conventional distillate fuel, as commercial marine engines for alcohols such as methanol are not yet available in the smaller engine segment. Although there are some smaller engines available that run on LNG, which is also a clean fuel, the infrastructure for LNG marine fuel supply is very limited. Requirements for methanol infrastructure are much simpler as it is a liquid at ambient temperature, and already widely distributed as a chemical commodity.

Development of methanol marine engines and fuel systems

One of the main goals of the SUMMETH project is to test and evaluate different methanol combustion concepts in a laboratory and to identify the best alternatives for the smaller marine engine segment. The work is focused on engines with power up to about 1200 kW and both Otto and diesel combustion concepts will be considered. The Stena Germanica project demonstrated that large engines (6000 kW) can be successfully converted to run on methanol. The SUMMETH project aims to show that this can also be done for smaller engines and vessels.

Methanol supply and infrastructure

Handling and storage of methanol is similar to that of liquid fuels such as diesel or gasoline. Thus it is considered to be relatively inexpensive to provide infrastructure for methanol fuel storage and distribution at smaller ports.

Methanol is widely used in the chemical industry in Europe and there is an established transport and distribution infrastructure in place. However, there is currently no specific infrastructure for marine fuels and the SUMMETH project will investigate possibilities for this. The feasibility of using renewable methanol as marine fuel will also be investigated.

Renewable methanol for lower greenhouse gas emissions

Although renewable methanol currently constitutes only a very small percentage of the methanol on the market, it has great potential for reducing greenhouse gas (GHG) emissions from shipping. Renewable methanol can be produced from many feedstocks, including municipal or industrial waste, biomass, and carbon dioxide. Methanol produced from wood, also called wood alcohol, may be one of the first examples of methanol production. In Sweden, renewable methanol has been produced via gasification of black liquor from a pulp mill.

Reductions in GHG emissions from renewable methanol on a “well-to-propeller” basis can be in the vicinity of 90% compared to emissions from conventional fuel use. Reductions depend on the feedstock and production method for the fuel.

Regulations for low-flashpoint fuels

Methanol is a low-flashpoint fuel and guidelines are currently in draft for incorporation into the International Maritime Organization’s recently adopted International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code).

The risk and safety analysis carried out for the SPIRETH project (Alcohol (Spirits) and Ethers as Marine Fuel), which was co-coordinated by SSPA and ScandiNAOS and tested methanol and DME as ship fuels, contributed to the development of the IGF code. It also contributed to the development of ship classification society rules for methanol as a ship fuel. The SUMMETH project will include a safety analysis for a methanol conversion of a road ferry and contribute to the development of safety measures for this ship type.

Growing interest in methanol

Other recent projects and developments regarding the use of methanol as ship fuel include the delivery in April 2016 of three methanol dualfuel chemical carriers to be chartered by Waterfront Shipping – these are the first newbuild vessels to use methanol as a fuel.

SSPA recently completed a study for the European Maritime Safety Agency on the use of methanol and ethanol as alternative fuels in shipping, with results presented at the European Sustainable Shipping Forum in January 2016. As well a 2016 report by the European Commission’s Joint Research Centre on alternative fuels for marine and inland waterways concluded that methanol and LNG are currently the most promising for shipping.

These and other studies are showing that methanol is a viable alternative fuel for improving the environmental performance of shipping.

Photos and illustrations:

The SUMMETH project will investigate the conversion of smaller vessels such as road ferries and pilot boats to methanol operation to reduce emissions of air pollutants. Photo: Joanne Ellis.

Sustainable methanol can be produced from renewables such as residue from the forest industry.

Methanol, with the chemical formula CH₃OH, is sulphur-free and burns cleanly, resulting in low emissions.