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Flexibility and hybrid have the (distant) future. Part 6 about alternatives to marine fuels.

15 November 2019

Flexibility and hybrid have the (distant) future – however, with two months to go, less than 10% of ships have been adjusted to comply with the new directive.

In part 6 of the series on alternatives to marine fuels, we look at what the most obvious solutions will be for the future. To sail cleaner, it is currently only possible for seagoing vessels to use cleaner diesel or to continue to run on heavy diesel and to have the exhaust gases run through a scrubber. LNG is becoming a good alternative: technically feasible and scalable. Other alternative fuels are all still in the development phase, but they are promised a bright future. There are various technological options, but why choose when a combination of new technology and (alternative) fuel offers more certainty.


An excellent alternative is a hybrid drive: partly electric and partly mechanical. Use is made here of both the advantages of electrically sailing at low power and the advantages of mechanical at high power.

One of the disadvantages of an electric drive is that a deceleration factor must always be considered when starting the engines. With a hybrid drive, the desired power is directly available via the mechanical component: fast response and instant power.

Also, in terms of maintenance, a hybrid scores better than the standalone mechanical or electrical drives. Due to the smaller number of engines running hours, less mechanical maintenance is required. That means less downtime per year and therefore not only less costs, but also higher employability. And for an electric drive system sec a heavy installation is needed. The electrical installation of a hybrid system, which is only used at low power, is 10 times lighter and requires fewer components. This finds also has a positive influence on maintenance.

In the tugboat sector, hybrid sailing seems to be the norm. For the combination of waiting for low power and providing full power service, a hybrid installation is the ideal drive.

A hybrid ship is also a good solution for ferry services and possibly a first step towards fully electric sailing. Stena Line is experimenting with electric ships: batteries with a total capacity of 1 megawatt hour have been installed on the Stena Jutlandica, which sails between Gothenburg and Frederikshavn. The vessel can then switch to battery power when maneuvering during docking. An extensive battery capacity of approximately 20 megawatt hours is then connected to the propellers. This makes it possible to sail around 10 nautical miles on electricity. In a next step that will be increased to 50 nautical miles with a battery capacity of 50 megawatt hours. The batteries are charged when the ship is connected to shore power, which is an important point for clean energy. However, the batteries can also be charged while using the ship’s generators.

Olietankers versus droge bulk schepen; één pot nat? 1

LNG as a (provisional) alternative

Sea-going vessels cruise the seas for most of their time, while maneuvering only takes up a small part of the action. A hybrid drive is not (yet) an alternative for these seagoing vessels. But less than 10% of the ships are equipped with a scrubber and alternative fuels do not yet have a large share in the fuels. Soon, therefore, most ships will initially switch to MGO or ULSFO. The problem, as outlined earlier, is the production and delivery of this fuel, and with it the high costs that come with it.

In view of the costs for and the first scarcity of low-sulfur fuel, the question is whether shipowners and ship managers will comply with these IMO regulations. An IMO member state cannot unsubscribe from the IMO guidelines, but each IMO member state can determine the sanctions for non-compliance with the guidelines.

In light of these provisions, Indonesia announced in July that it would not oblige ships flying the Indonesian flag in national waters to adhere to the sulfur rule: the implementation costs are too high for shipowners. Only if the delivery of MGO or ULSFO within Indonesia functions properly, will the directive for Indonesian ships be complied with. Meanwhile, foreign ships sailing in Indonesian water must comply with the IMO directive. And of course, Indonesian ships on international routes too.

But at the end of August, the Indonesian Transport Minister withdrew this ruling. State oil company Pertamina will produce 380 million liters of fuel with a maximum sulfur content of 0.5% per year. From the beginning of next year, the company will set up points of sale for the low-sulfur fuel in the port of Jakarta and from a floating storage facility for Balikpapan in the province of East Kalimantan.

LNG is a good alternative for new ships in particular, given the technical possibilities and the available and planned infrastructure. But this is also an interim solution, since LNG still has substantial CO2 emissions.

What will the future look like?

There is no crystal ball to predict which fuel or technology will become common in the future, until 2050. Economic and geopolitical developments, future energy policy and technological development are some of the uncertain factors that will influence this. Seagoing vessels sail worldwide and need a fuel that is available worldwide. In order to respond to the uncertainties of the future and also to meet environmental requirements, installing engines that can be relatively easily adapted to environmentally friendly fuels are the most opportune. It is therefore obvious to opt for dual fuel, given the flexibility that these engines bring with it, reducing the risks. Current fuel consumption is more flexible and with a (slight) adjustment, the engines are suitable for future fuels.

Ships in the shortsea segment are usually smaller than the deep-sea vessels. The way in which these vessels are deployed is also considerably different than the way in which deep-sea vessels are deployed. Where deep-sea vessels sail steadily for a long time over the sea, shortsea vessels travel shorter distances and the power requirement is variable. This makes it attractive for these ships to sail with a hybrid propulsion system or electrically. DNV-GL has conducted research into, among other things, the energy mix in 2050. LNG will be the most important fuel with more than 40%. HFO with scrubbers is good for 10%, while LFSO and MGO together will be good for 9%. It is striking that ammonia takes up a quarter of the mix. The remaining 15% is taken up by other fuels, such as biofuel and hydrogen.

Flexibiliteit en hybride hebben de (verre) toekomst - echter, met nog twee maanden te gaan is nog geen 10% van de schepen aangepast om te voldoen aan de nieuwe richtlijn. Deel 6 uit de serie over alternatieven voor scheepsbrandstoffen.

For deep-sea vessels, a dual-fuel propulsion seems to be the most future-proof investment, with the flexibility that these systems bring with it being able to switch to potential fuels of the future.

Hybrid drive seems to have the future for the shortsea sector. The efficient hybrid systems give lower consumption and the associated lower costs, greater range, higher reliability, lower maintenance costs, lower emissions and a simple operation.

And what is the current state of affairs?

The EGSCA (Exhaust Gas Cleaning Systems Association) expects that by 2020 at least 4000 ships will be equipped with scrubbers, which is approximately 7% of the total number of ships that must comply with the new directive. In 2020, 150 ships will sail on LNG, and another 150 will be on order; this number represents approximately 0.5% of the total number. Finally, 300 ships (sailing and on order) are registered with the Maritime Battery Forum, also about 0.5% of the total. This means that only 10% of the total number of ships that must comply with the directive is indeed equipped for this, 90% of the ships continue as before. For the near future, the alternative fuel is MGO or ULSFO – without measures it is the fuel that will be sailed on.