No faith in sulphur-free living?

In view of tougher restrictions on sulphur content in marine fuel to be effective from 2020, international companies and classification societies are searching new fuel alternatives while scientist are warning about implications of using low sulphur fuel for fuel systems.

Smells like ammonia

DNV GL predicts the future energy mix of the world fleet. The total energy use in international shipping is forecasted to rise to about 210 Mt of oil equivalent in 2025. It will then decrease to 170 Mt in 2050, with the container (23%), bulk (16%) and tanker (13%) segments accounting for the largest shares.

DNV GL experts say that in all the pathways, liquefied methane has a dominant share of 40 to 80 per cent of the fuel mix in 2050. However, ammonia is the most promising carbon-neutral fuel option for newbuilds.  The preference for ammonia is due to the lower cost of the converter, storage and the fuel itself compared with H2 and liquefied biogas (LBG)/synthetic methane.

For the “current policies” pathway, the model anticipates a partial transition to other fuels, the energy mix in 2050 being 93 per cent fossil fuels, specifically 50 per cent liquefied natural gas (LNG) and 43 per cent liquid fuels. High LNG uptake seen in all modelled pathways is driven largely by gas fuel prices, which are expected to drop towards mid-century.

In all scenarios, shore-based electricity provides about 5 to 7 per cent of the total energy consumed by ships in 2050, delivered via batteries and shore-to-ship power. The service and passenger segments will have the highest share, with almost 18 per cent of their energy provided by grid electricity.

Use of heavy fuel oil (HFO) with scrubbers depends largely on price differences between HFO, LNG and low-sulphur fuel oil/marine gas oil. In all modelled scenarios, the price favours HFO with scrubbers. In the “current policies” pathway, the share of HFO with scrubbers in the fleet fuel mix is 17 per cent.

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“Our modelling shows that achieving IMO GHG reduction ambitions is challenging but possible,” summarizes Tore Longva, Principal Consultant, DNV GL.

The weak side of such long-term forecasts is too many assumptions. For example, the decrease of LNG prices by mid-century is questionable. Also, it is hard to predict technical and economical viability of new fuel alternatives.

Fuel prospects

Meanwhile, market players are searching for new fuels complying with IMO requirements. A.P. Moller - Maersk alongside with Wallenius Wilhelmsen, BMW Group, H&M Group, Levi Strauss & Co. and, Marks & Spencer to explore LEO - a blend of lignin and ethanol - that could be part of the future solution for sustainable shipping.

Lignin is a structural bio-polymer which contributes to the rigidity of plants. Lignin is isolated in large quantities as a byproduct of lignocellulosic ethanol and pulp and paper mills. Currently, it is often incinerated to produce steam and electricity.

Copenhagen University is currently running the laboratory-scale development of this potential marine fuel. The project aims to move into phase II – testing the fuel on actual vessel engines – in the second quarter of 2020. Following a successful phase II, phase III will begin – the scaling up of LEO fuel production.

Ecofriendly - inefficient

Not only is the use of environmentally friendly types of fuel costly, it is also harmful for ships. While on the subject of biofuel expected by DNV GL to play a significant role in the future, it should be noted that LuminUltra, Canada-based microbial monitoring specialist, has recently share its concerns over the quality of some compliant fuels as the shipping industry gears up towards meeting the International Maritime Organization’s sulphur cap.

Commenting on the blending of biodiesel with HSFO and distillates, which go towards reducing the amount of SOx emitted during the combustion process, Patrick Taylor, LuminUltra’s newly appointed Director of Global Business Development, said: “The addition of biodiesel will reduce the sulphur content, but ship operators do need to be aware this can result in increased microbial influenced  corrosion (MIC). Less sulphur means more bugs.”

Taylor pointed out that the high sulphur content of residual fuel has been an “excellent inhibitor”, preventing the build-up of microbial growth and, consequently, the microbial induced corrosion of fuel tanks and systems.

“There is an increased biodiesel content in Marine Gas Oil (MGO) and we are seeing HSFO now being blended with recovered distillates to reduce the sulphur level. As biodiesel has a high water content, these new fuels can be nutrient-rich breeding grounds for microbiological growth. There are real risks, real safety concerns,” he said.

MIC tends to fall into two camps: aerobic, where microbes require oxygen, and those that don’t, anaerobic. Water is the elixir of life for both these types, with microbes requiring little to form colonies and expand.

Yet while there is still a lack of information on water absorbance in biodiesel/diesel blends, research has shown that at constant relative humidity, biodiesel absorbed 6.5 times more moisture than diesel.

Referring to a paper published in 2016, in Volume 108 of International Biodeteriation & Biodegradation, published in 2016 by Elsevier, Taylor said that a strain of fungus degraded biodiesel at “a phenomenal rate” and resulted in enhanced 1018 steel corrosion due to acidification.

“If compliant fuels are not regularly monitored for their microbiological content, then at the very least biofilm will form and clog up the fuel filters. In the worst case, if microbial growth goes unchecked, then we are likely to see an increase in rapid microbiological induced corrosion of even the most well-maintained fuel tanks and pipework”, emphasized Patrick Taylor.

There is another risk for today and the nearest future. Low-quality LSFO can appear in the global bunkering market, David Gauci, Manager of Quality and Tests Department, Saybolt (engaged in inspection of oil products), said at the 12th international Argus Russia and CIS Oil Products 2019 conference in Moscow. According to him, that can result in filter clogging. Besides, there is risks associated with mixing different batches of LSFO. Unlike HSFO, low sulphur fuel oils feature poor compatibility due to application of different blending technologies and components.

Back to the future

Long-term forecasts concerning the global bunker market are based on toughening of IMO requirements. However, when speaking about the coming 30 and more years we should comprehend that the new generations will probably reject the current trend towards exaggeration of environmental problems since it considerably decreases the quality of life amid increasing expanses.

According to experts asked by IAA PortNews, lobbying of environmental restrictions is based not on real scientific findings about the effect of anthropogenic activity on climate as much as on promotion of certain groups’ interests – those of NATO states popularizing rejection of heavy fuel because of its “sulphur footprint” (not surprisingly as biofuel is in active use by the US Navy) and manufacturers of dedicated equipment as well as countries having no oil reserves and, consequently being not able to compete in the bunker market with Russia, for example.

Therefore, more and more countries refuse to introduce new restrictions complying with IMO requirements in their waters. So, it's quite possible that the surge of shipping costs after 2020 will finally lead to a “fuel counterrevolution”, namely to the return of current regulations. Of course, that is just our pure speculation. Anyway, new environmental requirements contribute to unpredictability of the global shipping, hence careful attitude to long-term forecasts in this respect.

Vitaly Chenov

The article content includes information available from DNV GL and other companies.

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