Analysis counters challenge’ to LNG’s environmental benefits

Paul Gunton

Paul Gunton · 15 April 2019


An analysis of the well-to-wake (WtW) impact of using LNG as fuel that was released last week (11 April) was a response to “a frequent challenge” that claims LNG fuel’s greenhouse gas (GHG) benefits are negated by emissions generated during its production.

“This erroneous statement has been repeated and repeated so we felt it necessary to make a full well-to-wake analysis,” said Steve Esau, general manager of the pro-LNG industry group SEA\LNG.

Peter Keller, chairman of SEA\LNG and former executive vice president of TOTE

Along with the Society for Gas as a Marine Fuel (SGMF), it commissioned a study from the German consultancy thinkstep which shows that, when compared with using HFO, LNG fuel produces 21% lower WtW GHG emissions when it was used in two-stroke engines.

But it also showed that the benefit measured 28% better when the comparison was made for the final step in the process, from tank to wake and the report’s author, Dr Oliver Schuller, principal consultant at the German consultancy thinkstep, confirmed that this indicated greater GHG emissions during production of LNG compared with HFO. That is because of the energy needed to cool the gas -163°C, he said. Nonetheless, “if you integrate over the whole lifecycle, from a holistic perspective the environmental performance is better.”

They were both speaking to ShipInsight after presenting the findings of the peer-reviewed study, which “confirm LNG as a major contributor in meeting IMO’s 2050 GHG targets for shipping,” the two organisations said in a statement issued to coincide with their presentation.

That statement linked this benefit from using LNG to IMO’s goal that shipping will reduce its global emissions by at least 50% by 2050 compared to 2008 so ShipInsight asked IMO’s secretariat whether its targets were defined in a way that takes account of WtW savings. A spokesman said that current measures, such as EEDI, “deal with bunker tank to propeller emissions, but there is room within the GHG strategy for a wider approach to be taken should the member states [collectively] wish to do so.”

Mr Esau said that SEA\LNG has spoken to IMO about its research and offered to arrange a seminar about its result and pointed out that the SGMF is a recognised by IMO as a non-government organisation, which gives it a seat in IMO’s debating chamber.

Peter Keller, chairman of SEA\LNG and formerly executive vice president of the US containership operator TOTE – which has two LNG-fuelled ships – also spoke during the presentation and acknowledged that LNG on its own will not meet IMO’s goals. “We’re saying it’s a potential path towards that,” he said.

He believes that technology developments will reduce methane slip in future engines and improvements in LNG production will have an additional positive effect. Bio-gas and synthetic LNG could also help reduce GHG emissions, he said and “if you look at some of the changes that might take place in EEDI that the IMO and others are pushing [for], all of a sudden you’re starting to move in that direction.”

There will be a follow-up study to explore these topics, to be called A pathway to 2050, he said. “We certainly see the path. It’s just going to be a question of how many other pieces come into that path.”

During the discussion following their presentation, the panellists were reminded that LNG is seen by many as only an interim solution because of the large per-ship carbon emission reductions needed to achieve IMO’s target of at least 50% across the industry. In January, for example, the president of Clarkson Research, Dr Martin Stopford, suggested that a switch to an alternative fuel would be needed to achieve that goal.

Mr Keller agreed. “They are probably right and we’ve never said that LNG was the be-all and the end-all. It is not.” But it is “the only alternative fuel that is available right now that moves us in a direction that takes care of the air quality issues,” he said. “There are more goals than just the carbon goal,” such as the sulphur cap coming into effect from 1 January 2020, which LNG solves, he said.

Eventually, shipping will need to move to non-fossil fuels, he said, but no one knows how long it will take before alternative fuels have become “viable, sustainable and scalable. We can only sit and say that there is going to be a future ‘magic elixir’ for so long,” he said.

Questions were also raised about the accuracy of the engine data used in the study, which came from engine manufacturers, but Dr Schuller said that it had been subjected to a critical review and defended its use, saying that the manufacturers are the only organisations holding current data across different engines and load points. He also saw benefits in having data on both LNG and HFO from the same sources. “They have the primary data. It is a technically-based fact comparison,” he said.

There are no plans to extend the work to include data obtained from ships, but some ship operators are making their own measurements, Mr Keller said. He particularly mentioned TOTE and indicated that other SEA\LNG members were doing the same. “We will use the studies that our members do on [their] ships and we’ll certainly look at other operators of LNG ships and see what sort of data they’re developing.”

The full report can be downloaded from thinkstep’s website

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