Assessing and preventing methane slip from LNG engines in all conditions within both existing and new vessels (ZEWT Partnership)

Nearly all commercial vessels in operation today have a power generation based on one or more Internal Combustion Engines (ICE). Directive 2014/94/EU on the Deployment of Alternative Fuels Infrastructure defined minimum requirements for the building-up of alternative fuels infrastructure e.g. for natural gas. Currently Liquefied Natural Gas (LNG - methane) is an alternate viable marine fuel deployed to substantially reduce ship-borne pollutant emissions.

However, the impact of LNG on greenhouse gas emissions is strongly influenced by “methane slip”, including the release of unburnt LNG from LNG-fuelled ICEs. This is a problem that is being tackled but not fully solved.

Since methane is a greenhouse gas 84 times more potent than CO2 on a 20 year basis, the potential release of unburnt methane substantially increases the fuel’s impact on climate change. Whilst it is known that operations under some engine loading conditions and with some engine types can significantly increase methane slip, there is a lack robust data on the scale of the challenge for the existing LNG fleet and for new vessels.

Projects will address the current state of the art and the scatter of emissions between different types of LNG-powered engines. Operational data on methane slip from existing engine installations will be assessed, compared and made available. Activities may include additional measurement campaigns of methane slip where necessary and duly justified, addressing the complexity of different engine types at different load factors (including highly dynamic loads) and operational profiles. Activities will lead to a better understanding of the parameters involved in order to develop the most efficient abatement strategies through ICE improvement and/or post-treatment technologies. Such activities are expected to go significantly beyond existing measuring campaigns and provide distinctively new knowledge. A repetition of measurements already made by producers of large marine engines will not be funded.

Project(s) will develop and demonstrate such strategies and the corresponding technologies for better performing ICEs and/or after treatment systems which virtually eliminate methane slip in all conditions in refitted or newly built vessels. By developing technologies also suitable for retrofitting this action will also have an impact on the existing LNG-powered fleet whilst ensuring that negative impacts on energy efficiency (potentially resulting in higher CO2 emissions) and on the suppression of pollutant emissions (in particular NOx) are avoided.

This topic implements the co-programmed European Partnership on ‘Zero Emission Waterborne Transport’ (ZEWT).