Larger hybrid Ro-Ros loom

Ferries will operate on charter, said the company manufactures the cells it uses by itself, not only in a unique way that is unmatched by others but with a roadmap dedicated for Industrial application.

Leclanche cells have a life cycle up to four times longer than that of its competitors, Clement continued, adding: “So, for a given operation profile, we can achieve more with less and so have a smaller battery pack

The company’s cells are water cooled: not only it is better for the life time of the battery pack, but it also means that there are no hot spot but even temperature across the pack. It also allows modules to be close to each others for a smaller and lighter solution.

Half a dozen new energy storage technologies to come to market

Looking at the outlook in the battery pack sector in general, Senior Advisor Vesa Marttinen at the Finnish consultancy MarineCycles said that China currently produces 95% of all the electric buses in the world.

Ship design work itself is about iterating compromises – it is based on a spiral on which progress is made by optimising the entity. The future needs of markets – revenue drivers, in other words – and costs that arise from regulation, energy and crewing etc. seek a balance.

This happens through the interaction between the needs of a specific route – the operator’s point of view – and that of the resale value of the vessel, which is the owner’s point of view. Regulators that occasionally favour some technologies over some others can mix this pack of cards, which is otherwise governed by pure market forces, he said.

“If we talk about crossing the (English) Channel, internal combustion engines can be removed from ships in 10 years’ time. However, if we look at a crossing that takes more than six hours, battery packs take up too much space. Fuel cells remain at an early stage of development as well, although they were first tested onboard roro vessels some 15 years ago,” Marttinen noted.

However, both China and the European Union invest heavily in developing battery pack technologies: new generations of energy storage solutions will take up less space, which will enable the use of them to power ferries on overnight crossings in the future.

“Other considerations to bear in mind include positioning voyages between various operating regions, which are a challenge to battery powered vessels. One also has to remember that safety is a guiding principle in shipping: there is still work to be done in fire safety of battery packs and the safe return to port rule must always be met,” he concluded.

Battery pack fi re safety gains prominence

As battery pack installations on board ships become larger and larger, the question of fi re safety also becomes increasingly important, but in case of a fi re in a battery compartment, the challenges diff er materially from those in case of a fi re in a conventional engine room.

“For vessels with battery systems we have a mandatory class notation, BATTERY (SAFETY, POWER). These rules have seen frequent updates given recent fires and as more research has been completed,” said Anders Tosseviken, Senior Principal Approval Engineer at DNV

Andreas Ullrich, Global Market Leader, Passenger Ships & Ferries at Bureau Veritas noted that while safety is covered by SOLAS, as of today, it does not include specific rules covering the installation of large lithium-ion battery packs on board.

“BV has developed specific requirements in this respect. In a nutshell, it requires a specific project risk assessment, and provides rules for battery testing, certification and installation onboard. For every installation our rules requires a HAZID (hazard identification study) to be performed to assess the risk and agree on mitigating measures. This should be done preferably at an early stage of the design,” he told The Motorship.

As far as hybrid vessels are concerned, the question of redundancy is not an issue, but certain details should be borne in mind to avoid black out situations. “In general there should in those cases no issue with redundancy, however a proper power management system should be installed to avoid among others failure sequences which might lead to a black-out. This will as well be checked during the aforementioned HAZID,” Ullrich noted.

In general, on a hybrid vessel fitted with both diesel-generators and a battery pack for the purposes of both propulsion and main source of power, compliance with SOLAS requirements is ensured by the diesel generators.

Sverre Eriksen, Senior Principal Engineer at DNV pointed out that the principles of SOLAS require redundancy in the main source of power, e.g. two gensets or one genset and one battery. “When all the main sources of power is based on batteries only, the main sources of power shall consist of at least two independent battery systems located in two separate battery spaces,” he continued.

Ullrich said that in the case of a SOLAS vessel relying only on batteries for propulsion and main source of power, it is to be demonstrated that the level of safety is equivalent to that of a conventional design (complying with the requirements of SOLAS II-1/41) through the alternative design approach.

Should a fire break out in a battery compartment, the challenges differ significantly from such incidents in conventional engine room, DNV’s Tosseviken said. “The off-gases from Battery fires include hydrogen (H2) and methane (CH4). In addition, heat is generated from the thermal runaway. The challenge is therefore very different from what we face in case of a “standard engine room fire” involving marine diesel oil or heavy fuel oil.”

The DNV class notation suggest primarily freshwater based water mist for protection of battery spaces. “Other systems with two shots of gas with increased design concentration can be applied when it is documented that it can extinguish the relevant off-gases,” he said, adding: “Use of seawater is not recommended at this will short circuit the damaged part of the battery. This makes the fixed fire extinguishing system essential. It has to be designed in a robust way as sea water fire hoses can only be applied for boundary cooling for the battery case.”

BV’s Ullrich said that fire-fighting systems installed in battery rooms are intended for ship safety and are to be compatible with the specific battery chemistry, and the adequation of the fixed fire-extinguishing system to the battery type is to be documented.

“Several extinguishing media may be considered, including fresh water, foam, inert gases etc. Aim of the systems is to mitigate the risk, to get temperatures down and to avoid spreading of the fire. If battery packs are installed in the engine room and not in a dedicated battery room, the hazards created by batteries need to be considered especially from a fire risk point of view. This will be incorporated in the HAZID required<’ he concluded.