Climate impact of LNG fuelled ships

Over the past few months the climate impact of LNG fuelled ships have been discussed in several media. It seems it has come as a shock to journalists that LNG fuelled ships will not save the world from increasing temperatures after all.

First of all, LNG fuelled ships have been promoted and developed primarily for their indisputable positive impact on local emissions: Compared to oil based fuels, there are practically no emissions from LNG fuelled ships. It has also been stated that on top of this, there is a CO2 advantage, as the emissions from the combustion process are less. This comes from the simple fact that of all the fossil fuels, methane has the smallest amount of carbon atoms compared to hydrogen atoms in the molecules. So by chemical composition there is less carbon per content of energy, hence less CO2 is produced.

The journalists though seem to enjoy spinning up a story that LNG is not doing anything for the climate, perhaps even having a negative impact. And they seem to base their logic on two aspects:

  1. Emissions of uncombusted methane from the engines
  2. Emissions of CO2 through the value chain from well to engine

On both aspects, the journalists draw false conclusions:

  1. For emissions of uncombusted methane they base their data on the first LNG fuelled marine engines ever installed, they miss the point that these engines are no longer in the product line of the suppliers. The new engines currently being promoted by the manufacturers and installed in new ships greatly reduce the discussed methane slip. We already discussed this in an earlier blog post when the topic was raised by a Norwegian industry magazine, Teknisk Ukeblad.
  2. For lifecycle emissions from well to engine, there is no basis for shredding doubt of the performance of LNG. We are aware of two scientific studies addressing this issue, one performed by Chalmers University in Sweden, the other by TNO in the Netherlands. Both studies conclude that emissions from well to engine, i.e. excluding the combustion itself, are similar for oil and natural gas products, with a slight advantage for LNG. This means that the 20-25% reduction the engine suppliers are claiming for the combustion is not cancelled out by emissions elsewhere in the value chain.

It is worrying to observe that there is an increasing scepticism towards a measure that clearly has huge positive effects on local air quality because people uncritically buy into eachothers false perceptions.

It is even more worrying to see that these false perceptions are bought into by industry people and not only journalists. An example of this was last week’s blog post by Lloyds Register where Nick Brown states “there may in fact be legitimate concerns that LNG does not reduce CO2 emissions on a like-for-like basis with other fossil fuels“. I would really like to know what the basis for the legitimacy is… hopefully not only information from newspapers?

LNG will not save the world, but it is a contribution in the right direction

7 Comments , ,
  1. Anja Schilling

    Thanks for this interesting blog, which sheds light on how quickly misinformation is spreading out and being taken for a fact. Nevertheless, to me (not a journalist myself, but a communications professional) it sounds disrespectful to write “journalists though seem to enjoy spinning up a story”. I think and hope, your blog is read by quite a few journalists, and this sentence might just be perceived as arrogant or overly negative, suggesting that the media actually deliberately twists facts – maybe the facts had simply not been understood. Looking forward to your next blog, though!

     
    • Hi Anja,

      Thanks for your comment. I agree it sounds a bit hard on the journalists. And I would like to highlight that I mean no disrespect to journalists in general. But sometimes the facts come out so twisted it is hard not to be frustrated.

      Again, no offence to journalists in general.

       
  2. Eirik Nøtsund

    First of all I would like to say that I really find this blogg interesting and that there are a lot of good ideas and interesting subjects being discussed.

    I know it might be a bit late to post a comment for this post but I will give it a go anyway.

    You are discussing false perceptions brought up by journalists and people in the industry and also refer to Nick Brown`s blogg where he mention the concern that LNG fuel does not reduce CO2 emissions on a like-for-like basis with other fossil fuels.

    I am not sure where these legitimate concerns come from or what Brown base his perceptions on, but I found something interesting on Siemens Norway offiicial webpage (http://www.nwe.siemens.com/norway/internet/no/produkter/energy/marine/Documents/Orig.SKIP.10nr.2_2011_72dpi.pdf).

    It is here claimed that Siemens together with Østensjø Rederi have developed a new diesel- electric propulsion that produce less GHG than all existing diesel and gas engines. The article claims that MARINTEK has verified the environmental effects of this new propulsion so the facts should be legitimate. In addition the the environmental effects compared to gas propulsion will the investment costs for this type of engine be 9-10 million USD less.

    I am however pretty sure that the new LNG engines being developed today can provide excelent emission figures compared to earlier, but I think it is important to remember that diesel engine technology is also developing and becoming more environmental attractive. And if there is any truth in this article I am sure diesel propulsion will continue to be preferable in the years to come.

    Look forward to some respons:)

     
    • Hi Eirik. Thanks for your comment.

      I heard about the solution developed by Siemens and Østensjø, and the way I understand it they have taken the operational profile of the ship into account and designed an engine arrangement that ensures that the amount of minimal load on engines are minimized. I don’t understand how this is relevant to the gas versus diesel discussion. Gas engines could be used also in Østensjø’s set-up and the results should be even better.

      It is, however, very relevant to observe that all types of ships can reduce fuel consumption considerably just be optimizing the design against the operational profile instead of the service speed. This is a typical low hanging fruit in my mind, and is no excuse not to also look at LNG.

      Lars

       
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  4. Kyle Ash

    I just noticed this post while researching LNG projections. If you have not see two US studies on life cycle GHGs associated with NG, they are quite relevant. The comparisons are not with bunkers, but with coal. The Jaramillo study includes analysis on different forms, and combustion methods of NG and coal.
    This study shows that GHG emissions associated with LNG in a range could be higher than for coal. Energy production required in liquefaction and regasification are major culprits. The Jaramillo study did not consider higher GHG emissions associated with nonconventional gas (i.e., fracking, ref Howarth study) which has been independently studied and found higher than coal also. So, LNG produced with nonconventional gas is arguably no better than coal for associated GHG emissions.
    -Jaramillo, P.; Griffin, W.M; Matthews; H. S. “Comparative Life Cycle Air Emissions of Coal, Domestic Natural Gas, LNG, and SNG for Electricity Generation.” Environmental Science & Technology. 2007; 41 (17); 6290-6296.
    -for Howarth’s work, see http://www.eeb.cornell.edu/howarth/Marcellus.html

     
    • Hi Kyle,

      I am aware that there have been a few more studies out since I published this blog post, but to be honest I have had trouble getting an overview of the input. It does not appear logical to me that LNG is as bad as coal when it comes to GHG. It only requires some 10% of energy content to liquify and re-gas is not very energy consuming, so I dont see where all these emissions are coming from. After all, it is a chemical fact that there is less carbon in natural gas than any other fossil fuel, and this translates directly into less CO2 output. So if this advantage is lost versus coal, it must be because of some big inefficiency somewhere in the supply chain. And I dont see where it is. I suspect that the methane emissions used in these studies are some worst case indications, and not average natural gas production.

      We will stay on this, however, and our research department is tracking this. We will return to the topic when we are confident about the data.

      Thanks for commenting, it was a timely topic to bring up.

      Lars

       

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