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Hydrogen and fuel cells have huge potential in the shipping industry. However, nowadays there are still some regulatory, technical and operational constraints. Further R&D efforts are needed

To become green, the shipping sector will need to assess, adapt, test and validate innovative technologies, while shaping the international[ds_preview] regulatory framework. The use of alternative fuels and fuel cell technologies is in line with the IMO target of reducing the total annual GHG emissions by at least 50% by 2050 compared to 2008 and the EC decarbonisation policy of the maritime sector, with short and medium-term measures, where full decarbonisation by 2100 is the ultimate goal.

Reward system needed

Future propulsion power will be diversified and hybrid in nature. In hybrid ships, energy storage devices are critical for optimising the use of energy. Energy storage technologies currently available are mainly used for battery powered propulsion systems, useful also for energy peak shaving. This technology has already been developed and is on the market for small ships. For larger vessels, hybrid battery solutions still have some challenges to face related to safety, cost and lifetime performance before they become competitive with conventional solutions.

Alternative power generation systems are already replacing diesel engines, often implying a fuel switch – LNG, biofuel blends, methanol/ethanol – and ultimately hydrogen. Fuel cells using suitable primary fuels offer a clear contribution towards the electrification of transport. Further advances in the automotive sector, (light and heavy road transport) and in shipping will boost the electric and hybrid electric powertrain market. Batteries or LNG powered ships are not fully meeting either cruising distance requirements or CO2 reduction targets. Advances in technology and infrastructure are still required to make these alternatives practical and viable in a life-cycle perspective.

In the meantime, a reward system for early adopters/users of zero carbon solutions should be set through favorable regulatory frameworks together with the introduction of policies to incentivise technology adoption. As already experienced with the implementation of LNG as primary fuel on board, effective deployment of these technologies will also require a new culture, efficient training, and coordination within a multitude of public authorities.

Energy efficiency commands a high priority within shipping companies, but the need to adopt fuel cells and hydrogen technologies is different in each maritime segment – yachting, fishing boats, small/large ferries, container or general cargo. Cruise ships, more than others, have the market forces, regulatory push, longevity (~30 years) and funds to invest, as well as the largest benefits should they adopt disruptive technologies and alternative fuels which can halve emissions. New cruise ships are now adopting LNG and are designed to be substantially more energy efficient (up to 20%) compared to their immediate conventionally fuelled predecessor.

Gap to land-based application

Fuel cells and hydrogen are clearly in the sights of the cruising industry and a number of operators have done significant work and invested in dedicated studies. However, cruise ships are still big energy consumers and their metrics (3.000–6.500 passengers, 32.000t fuel/year, 8+ MW power demand at port, 50+ MW max power demand at sea) shows that there is a gap when compared with other land-based applications (rail, automotive) typically concerning power levels less than 1 MW.

Currently, the maritime industry is focusing on the use of reliable fuel cells of about 2 MW. This size could satisfy the power demand in port of a number of RoRo and RoPax ships and – in a modular arrangement – be suitable for cargo ships and for cruise ships (with multiple fuel cell units in different zones).

The power demand for propulsion is much higher. Diesel fuels (HFO-MGO) have a volumetric energy content of approx. ~40–35 MJ/l, but these values decrease for non-conventional fuels suitable for fuel cells: LNG ~22 MJ/l, Methanol ~16 MJ/l, Liquid Hydrogen ~9 MJ/l.

This implies increased storage tank volume and more time for bunkering operations, since the global availability of non-conventional fuels does not support relaxing of the two-week autonomy required by most cruise operators. End users may require (size depending) 20–30t of liquid H2/day/ship, which is not only exceeding by far the demand for road & rail transport, but also the daily production capacity in EU. The production on board of hydrogen-rich fuel is not CO2-free, being the result of a reforming process from LNG or other hydrocarbons.

The diffusion of high-power fuel cells on board is limited by several factors: missing supply and distribution chain (bunker vessels/barges vs. fixed infrastructure at ports); fuel cells cost and life cycle (30–40.000 hours vs. ships lifetime of 30 years), maintenance (not yet compatible with five years dry-docking intervals), power density, fuel flexibility, dynamic power management. And, of course, the training of the personnel and the availability of a coherent regulatory framework (Regulations, Codes and Standards)

A life-cycle performance assessment (CAPEX and OPEX) is a puzzling exercise for any ship owner today, as long as fuel cell advantages (low/zero emissions, accessibility to environmentally protected areas, no noise, no vibrations, no smell, less rotating equipment) can hardly match the challenges and the uncertain costs of hydrogen-rich low-flashpoint alternative fuels.

Fuel cells for big ships are just at the beginning of their development. The industry has to come up with concrete solutions that operators could adopt and synergies are yet to come that could take place with ports close to smart cities already considering hydrogen use.

Yet, high-power multi-MW fuel cells are the key towards clean & green power generation systems for the maritime industry. Fuel cells if they can be developed at a multi MW scale may become the primary source of energy for large-scale shipping, outside of yacht and small auxiliary power applications.

Intensive R&D is therefore needed in order to change the game and develop fuel cell technology, which will make it feasible to install multi MW systems as primary source of power. To that end, not only will the waterborne sector in Europe need to make significant investments in R&D but also in education and the training of the entire supply chain. These investments need to be underpinned by an integrated, holistic and coordinated policy and strategy.

In this context, RINA issued new Rules for Fuel Cells installation in ships (FC-SHIPS 2018), already consistent with the developing international regulatory framework and coordinated on behalf of the Italian Administration input to the IMO CG on the Amendments to the IGF Code (new draft Part E on fuel cells) and the development of guidelines for low-flashpoint fuels.
Alessandro Maccari