Environmental assessment of Sweden-related LNG fleet in the Baltic Sea and the North Sea
The objective of this study is to provide estimates of emissions from the liquefied natural gas (LNG) fuelled ships related to Sweden, and to outline benefits for society through reduced external costs of air pollutants and greenhouse gases from fuel shift from marine gasoil (MGO) to LNG. The total societal benefits from the Sweden-related LNG fleet in 2017 are estimated at 17.4 million €2010. This estimate includes reduced health and climate impacts and reduced crop damage.
The largest contributor to the benefits is positive impact of emission reductions on population health. Lower emissions of primary particles (PM2.5), nitrogen oxides (NOx) and sulphur dioxide (SO2) from LNG vessels, compared to a reference fleet running on MGO, result in lower concentrations of primary and secondary PM2.5 and ground-level ozone, and subsequently reduced premature mortality. Differences in emissions of main air pollutants between the analysed LNG fleet of 12 ships and a reference MGO fleet in 2017 are calculated to 100 tonnes of SO2, 160 tonnes of PM2.5 and 3 200 tonnes of NOx. The reduced NOX emissions correspond to the emissions from 24 300 average heavy duty trucks with an average mileage on the Swedish roads during the same year. Emissions of greenhouse gases (CO2 equivalents) are modelled to be similar for the LNG fleet and the MGO fuelled reference fleet: emissions of CO2 equivalents from the MGO fleet are estimated to be 6 ktonnes higher in 2017.
Estimated emissions for 2022 are calculated assuming that present and already ordered LNG ships run mainly on LNG. The difference in emissions between these ships and reference ships fuelled with MGO is then significantly larger and constitutes 385 tonnes of SO2, 540 tonnes of PM2.5 and 11 200 tonnes of NOx. Emissions of greenhouse gases in 2022 are estimated at 640 ktonnes CO2 equivalents for the LNG fleet and 660 ktonnes CO2 equivalents for the MGO fleet.