EMSA has published a study on the use of ethyl and methyl alcohol as alternative fuels for reducing both the emissions and carbon footprint of ship operations.
As they are sulphur-free, use of methanol and ethanol fuels would ensure compliance with the European Commission Sulphur Directive. The European Maritime Safety Agency (EMSA) commissioned this study to gain more information about the benefits and challenges associated with these fuels and to evaluate their potential for the shipping industry.
Methanol is widely available as it is used extensively in the chemical industry. There are large bulk storage terminals in both Rotterdam and Antwerp, and it is transported both with short sea shipping and by inland waterways to customers. Ethanol is the most widely used biofuel in land based transportation and can be found at most large chemical storage hubs in Europe.
Methanol and ethanol both have many advantages regarding environment impacts as compared to conventional fuels – they are clean-burning, contain no sulphur, and can be produced from renewable feedstocks. Emissions of both methanol and ethanol from combustion in diesel engines are low compared to conventional fuel oils with no aftertreatment.
Particulate emissions are very low, and nitrogen oxide emissions are also lower than with conventional fuels, although the amounts depend on the combustion concept and temperature. If a pilot fuel ignition concept is used with methanol and ethanol there will be avery small amount of sulphur oxide emissions which will depend on the amount and sulphur content of the pilot fuel.
The environmental impact of production and use of methanol “well to wake”, using greenhouse gas equivalents as an indicator of global warming potential, varies according to the feedstock. Methanol produced using natural gas as a feedstock has “well to tank” emissions similar to other fossil fuels such as LNG and MDO. Bio-methanol produced from second generation biomass such as waste wood has a much lower global warming potential than fossil fuels and is lower than ethanol by most production methods. “Well to wake” emissions from ethanol are lower than fossil fuels but the amount varies with production methods and feedstock. For example the ethanol produced in Brazil and in Sweden has much lower “well to tank” greenhouse gas emissions than that produced from corn in the US.
The behaviour of methanol and ethanol fuels when spilled to the aquatic environment is also important from an environmental performance perspective as ship accidents such as collisions, groundings and foundering may result in fuel and cargo spills. Both methanol and ethanol dissolve readily in water, are biodegradable, and do not bioaccumulate. They are not rated as toxic to aquatic organisms.
Prior to the recent oil price crash, methanol prices were below the price of low sulphur marine gas oil (MGO) on an energy basis for two years from 2011 to 2013, making it an attractive sulphur compliance option. With the low oil prices in 2014 and early 2015, methanol was comparatively more expensive but in late 2015 the price ofmethanol has started to move closer to the levels of MGO again.
The payback time analysis carried out for this study indicate that methanol is competitive with other fuels and emissions compliance strategies, but this depends on the fuel price differentials. Based on historic price differentials, methanol will have Ethyl and methyl alcohol as alternative fuels in shipping shorter payback times than both LNG and ethanol solutions for meeting sulphur emission control area requirements. With the current low oil prices at the end of 2015, the conventional fuel oil alternatives have shorter payback times.
Further information may be found by reading the study below