The Dutch cooperative venture Feadship recently completed the first successful on-board sea trial of gas-to-liquids (GTL) diesel, finding that it has advantages as a partial solution to emissions. Sulphur emissions were reduced to zero, emissions of particulates (soot) and unburned hydrocarbons were reduced by 30%, while emissions of carbon dioxide and nitrogen oxides (NOx) were cut by 10%.
Bearing in mind the new emissions controls mandated by the International Maritime Organisation, Feadship considers these benefits to be worth the 10% price premium that GTL diesel commands, and is now considering switching to GTL diesel for further sea trials.
Signal spotted by Franck Violette
Image caption: Can Feadship see beyond incremental solutions to clean fuel at scale?
Image credit: Frans Berkelaar / Flickr
This is a signal with mixed implications. On the one hand, GTL diesel is a definite improvement over the heavy fuel oil currently in use in shipping, and it can be used straight away in existing ships without the need for a new engine. The syngas used to create GTL diesel can also in theory be generated from biogas, raising the possibility of near carbon neutral fuel. However in practice, the cheap and abundant availability of shale gas is a barrier to this.
Furthermore, while GTL diesel promises to be an easy short term solution, it is not necessarily the best solution that is available for commercial use. Liquid natural gas (LNG) has more impressive emissions reductions (20-25% for carbon dioxide, 85-90% for NOx, 100% for sulphur and particulates) and is also low cost, although it requires a refit with a new engine. A biogas version of LNG is also possible, although it suffers from the same barrier in practice mentioned above.
In conclusion, while it is welcome news that cleaner alternative fuels are being trialled in shipping, given the size and importance of the sector, there is a risk that the more convenient incremental solution (in this case GTL diesel) may crowd out better bridging solutions to a low emissions future.
Green4sea (2015, 10th July) First sea trial of gas-to-liquids synthetic diesel onboard