The Naval Architect: May 2019
Currently, there are over 30 LNG bunkering facilities worldwide and 143 LNG fuelled ships in operation with another 135 on order. In 2017,
there was only one functioning LNG bunker vessel, today there are nine. Despite this escalation in LNG related investments, some maritime experts and recent studies suggest that LNG is simply an interim fuel incapable of meeting the IMO’s future 2050 targets.
A report released earlier this month, however, backs LNG’s role in improving air quality and revealed its ability to cut Greenhouse Gases (GHG) by up to 21% across the fuel’s entire life cycle.
Commissioned by the not-for-profit industry group SEALNG and the Society for Gas as a Marine Fuel (SGMF), the study assessed the performance of LNG from Well-to-Wake – an approach which evaluates the fuel from production through to combustion – compared with conventional oil-based fuels.
According to the report, LNG can reduce GHG emissions between 14% and 21% in a slow two-stroke engine, which accounts for 72% of marine fuel consumed today. With a medium speed four-stroke engine, emissions dropped between 7% to 15%.
When examining the fuel with a two-stroke engine only during its combustion phase – Tank-to-Wake – GHG emissions were cut by up to 28% compared with heavy fuel oil.
The study investigated LNG’s performance in the most common marine engines – two-stroke and four-stroke – but did not take the vessel type or conditions into consideration.
It also confirmed that emissions from air pollutants, such as sulphur oxides, nitrogen oxides and particulate matter, are all near zero in comparison to oil-based marine fuels.
Conducted by Thinkstep, a global consultancy company headquartered in Germany, and reviewed by a panel of independent academics, the study began in May 2018. Primary data on both LNG and HFOs during usage in marine engines was provided by original equipment manufacturers.
Although LNG proves to be a feasible solution for improving air quality and meeting the IMO’s 2020 sulphur cap, it’s still a long way off from significantly decarbonising or eliminating GHG emissions.
So, what role does LNG play then?
“It will move the ball forward on IMO targets,” said Pete Keller chairman of SEALNG at a press conference in London.
Keller, who is also the executive vice president of Tote – the first company to operate LNG-fuelled containerships – admitted that LNG may be an interim fuel but stressed its current importance as the only practical option on the market.
“It’s the only alternative fuel solution that is available now,” said Keller. “How long is it going to take to develop a viable, sustainable, scalable solution with some of the other alternatives being discussed? We can only sit here and say there’s going to be a future magic elixir for so long.”
The future of LNG
Although LNG is in plentiful supply and has a mounting bunkering infrastructure, which makes it one of the most readily available ‘green’ options, its long-term capability depends heavily on future optimisations.
The degree to which LNG can reduce GHG depends upon the amount of methane slip incurred during the combustion process. But ongoing operational and technological advances could help enhance LNG’s initial benefits, said Keller, therefore lengthening its lifespan and carving out a pathway for LNG to meet 2050 targets.
Manufacturers are currently improving engine designs and introducing solutions such as methane oxidation catalysts to mitigate methane leakages.
“There is a potential for reductions of up to 40% or even 60% by using catalysts”, said Dr Oliver Schuller, the team lead energy and mobility at Thinkstep.
SEALNG’s study also noted the potential of bioLNG and synthetic LNG as a way of increasing emission reductions. It stated that “a blend of 20% bioLNG as a drop-in fuel can reduce GHG emissions by a further 13% compared with 100% fossil fuel LNG.”
The group’s next study will focus on what these different pathways to 2050 may look like.
“[LNG] is not the be all and end all, how far it will go and how long the path is until there are other opportunities, we don’t really know,” said Keller.