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Figure 1. The “Viking FellowSHIP”. A small-scale model powered by hydrogen and fuel cells. A full scale demonstration is planned to be realised in 2008, using gas fuel.

Fuel cell technology will soon be a reality in commercial ships. Up to 50 per cent more efficient than today’s diesel engines, fuel cells will in the near future transform the economics and environmental impact of commercial shipping. The DNV-led joint industry project FellowSHIP is developing and demonstrating the technology.

Developing fuel cell systems for ship use

By Tomas Tronstad, DNV Research & Innovation, Oslo, Norway
tomas.tronstad@dnv.com

Combining the continued use of fossil fuel energy with the growing call for sustainable development poses a global challenge. Compared with conventional power-generating equipment, fuel cell (FC) technology offers improved efficiency and large reductions of atmospheric emissions. The technology has reached a level of maturity that allows for large-scale industrial use, such as in ships. For the most established FC technologies, lifetime and reliability are approaching industry standards, and further technology improvements are signalled. The FellowSHIP project, initiated in 2003, aims to develop and demonstrate complete integrated hybrid fuel cell systems in ships, and to qualify the technology so developed for future use. Activities include onboard demonstrator of a 330 kW auxiliary plant, and a 20 kW prototype of a newer FC technology, both commissioning in 2008. Pending the future hydrogen infrastructure, the first demonstrators will be using LNG and methanol as fuel. The FellowSHIP technology will be up to 50 per cent more efficient than today’s diesel power while at the same time there will be no emission of NOx, SOx or particles. The CO2 emissions are reduced by 50 per cent compared to diesel engines run on oil. Life cycle cost analysis indicates that LNG driven fuel cells in a life cycle perspective will be from 30 per cent to 90 per cent more expensive than conventional diesel technology, based on today’s prices. In a future perspective, analysis indicates that owing to increased environmental fees and likely introduction of emission trading quotas, fuel cell driven ships will be economically favourable to conventional technology.

The background
Environmental concern is becoming increasingly relevant for all kinds of industry. To date, the environmental requirements imposed on the shipping industry have been relatively mild compared to land based industry, in particular regarding harmful atmospheric emissions. This is about to change, with a first example being the establishment of the Baltic Sea and the North Sea as environmental control areas, requiring ships that enter these areas to use fuel containing maximum 1.5 per cent sulphur or install exhaust cleaning systems.

As the oil price is rising, we see an increasing focus on energy use and the management of energy. Fuel cell technology offers high energy efficiency and good fuel flexibility. Fuel cell (FC) technology has been known since early last century. A milestone was reached with the launch of the first Apollo spacecraft, using fuel cells to produce electricity and potable water from hydrogen. The technology has been extensively developed since then, and the FellowSHIP project partners believe that FC technology now has reached a level of maturity so that it can be taken in commercial use.

The FellowSHIP project
In 2003, in co-operation with Aker Kvaerner Process & Automation Systems (now Wärtsilä Automation Norway), Eidesvik Offshore, MTU CFC Solutions, Vik-Sandvik, Wallenius Marine and Wärtsilä Corporation, Det Norske Veritas (DNV) made the initiative to establish a joint industry project, named the FellowSHIP – Fuel Cells for Low Emission Ships. This is in three phases, with the goals to develop, design, build, test and qualify industrial fuel-cell power packs for hybrid and standalone configurations. Phase I (2003–2005) included a feasibility study and concept definitions pertaining to solid oxide fuel cell technology (SOFC) and molten carbonate fuel cell technology (MCFC). The current phase II is split in two branches for further development and ship demonstration of these two fuel cell technologies respectively.

The systems being developed for MCFC technology will be suitable for maritime, offshore and land-based use. The project will develop fuel cell systems for auxiliary and propulsion ship power.

	Figure 2. The MTU fuel cell module, planned to be installed in an Eidesvik Offshore vessel in 2008.

Figure 2 shows the 330 kW molten carbonate fuel cell being adapted to marine use, developed by MTU CFC Solutions GmbH Germany. The ship candidate for the MTU technology is a newly ordered Eidesvik Offshore supply vessel. The fuel cell is being integrated in the ship by use of proprietary technology uniquely developed in the FellowSHIP project. Main electro-technical issues being addressed are solutions that will enable combined AC and DC systems. The systems being developed will maximise energy efficiency and protect the fuel cells so that it can tolerate the rapid transients of dynamic grids. Safety, reliability and risk analysis forms the basis of the first DNV approval, complemented with input and requirements from national authorities.

In total, this will provide the necessary confidence to all stakeholders. The systems being developed will be fuel flexible, and first demonstrators will run on LNG pending the necessary hydrogen infrastructure and maturing of hydrogen technology. Natural gas is a product easily available worldwide, is a mature product for being used as fuel in ships and on land, and is often cheaper than oil products. A hydrogen & fuel cells powered small-scale model size 1:84 of a supply vessel, the Viking FellowSHIP (see figure 1), was built and demonstrated at the ONS exhibition in Stavanger and at the SMM exhibition in Hamburg in 2006.

Figure 4. The Wärtsilä fuel cell module, planned to be installed in a Wallenius vessel in 2008.

Wärtsilä Corporation is another major European developer of fuel cells for maritime and other use. With a long-term commitment they are currently developing fuel cell modules utilising the SOFC technology, and the plans include introducing 250 kW plants in 2010. Wallenius Marine is planning to take a 20 kW prototype of this technology fuelled by renewable methanol onboard one of their ship in 2008. The concept basis was developed within the FellowSHIP project and will be further developed, analysed and set out in reality by the partners Wärtsilä, Wallenius Marine, DNV, LR and University of Genova, co-funded by EU.

Figure 4 shows the Wärtsilä SOFC unit. Within the EU portfolio of clean energy projects, this project is the only one looking at using renewable fuels for ships.

Benefits of fuel cells in ships
Fuelled by LNG, the FellowSHIP technology will be 50 per cent more efficient than today’s diesel engine technology. Fuel cells optimum efficiency is at some 30–50 per cent of maximum power, very much in contrast to conventional technology where part load efficiency is rather poor. Ships with a duty profile that include operations at part load will be especially favourable for installation of fuel cells. In such vessels, a fuel cell plant will imply dramatically reduced fuel consumption compared to conventional technology (diesel engines, gas/steam turbines).

A fuel cell imposes no harmful emissions to air. The only “exhaust” is heat and water. If fuelled by carbon containing fuels such as e.g. natural gas the exhaust will contain CO2, however reduced by up to 50 per cent compared to diesel engines run on traditional marine fuel. This is partly owing to the better carbon to hydrogen ratio in natural gas, and partly to the higher efficiency of the fuel cells. Fuel cell technology is inherently silent and vibration free. This caters for increased passenger and crew comfort as well as better working environment for the crew. The simpler designs with few moving parts require very little maintenance. Fuel cell technology is modular, and enables systems to be configured for efficient use of onboard space.

Studies of life cycle impact of fuel cell versus diesel engines carried out by DNV shows that the manufacture of fuel cells is harsher to the environment than diesel engines. This is due to the currently energy-intensive production of the stacks, mainly caused by lack of mass production. However, due to superior operational performance, a fuel cell run on LNG is despite this far better than diesel engines in all impact categories studied when accumulating the complete life span (manufacture, operation and decommissioning). The results vary from 45 per cent better to more than 90 per cent better, depending on the category studied.

	Figure 3. The working principle of a PEM fuel cell run on hydrogen. Picture courtesy of Fuel Cell Today.

The fuel cell working principle
and technology status
Typical fuels for fuel cells are hydrogen, natural gas, methanol, ethanol, biofuels, ammonia, carbon monoxide or even light diesel oil. The chemical energy bound up in a fuel is turned into electrical energy in the fuel cell, with the operating principle rather much like a battery. The electrochemical reactions accomplished require sophisticated material technology. The basic working principles are different for various types of fuel cells. Figure 3 shows the principles behind the basic hydrogen driven PEM cell, used in the Viking FellowSHIP, the small-scale ship model. In a fuel cell, the absence of a combustion process, which otherwise would produce nitrous oxides and particles allows for completely pollution free conversion of energy. In the case of hydrogen, the only by-products are pure water and heat. If a carbon containing fuel is used, the process also produces CO2. The technology is inherently silent and vibration free as there are no moving parts except for supporting systems such as fans, blowers etc.

Generally speaking, for the FC technology to match conventional power packs, the main technical issues to improve today are system life time and stack stability (reliability). There are different FC technologies, often categorised in low-temperature and high-temperature cells. The most developed low-temperature FC, often referred to as PEM, has an operating temperature below 100ºC, with a system electrical efficiency only marginally better than ICE. Such cells require hydrogen as fuel. Low-temperature FC lifetime is currently in the order of a few thousand hours. Low-temperature cells also need to improve efficiency when run on reformed natural gas and reduce investment costs (currently about USD 6,000/kW).

The most relevant high-temperature cells are the MCFC and the SOFC, with operating temperatures around 650 and 800°C respectively. These have some of the highest available efficiencies in the family of fuel cells, and besides hydrogen can run on a variety of fuels, including LNG, methanol and other natural gas derived fuels and also biofuels.

MTU currently have logged over 30,000 hours of operation on one of their MCFC modules. Focus on development of high temperature cells should be on handling of dynamic loads, reduction of power density and stack stability (reliability). Cost is also here an issue with MCFC currently about USD 4,400/kW.

Economical aspects
of fuel cell technology
Today, fuel cells have an investment cost (installed cost) of approximately six times that of diesel engines. Interestingly, owing to the diesel engines’ higher fuel consumption over the lifetime of a diesel engine, and calculating from today’s price of LNG and marine diesel oil, reduced fuel cost by using FC accumulates to about half of the extra investment cost.

Figure 5. Quantitatively cost of power equipment for different markets, and indications to cost of fuel cell technology.

Figure 5 indicates some of the markets for fuel cell technology, and illustrates qualitatively the cost of power for different alternatives. Roughly speaking, the cost increases about a magnitude between each step from automotive to industrial/marine to electronics. With mass production, fuel cell cost is expected to go down heavily in the years to come, opening new markets.

In a joint study, NTNU in Norway and DNV have performed studies of life cycle costs of fuel cell versus diesel engines. Rough indications using present technology costs is that LNG driven fuel cells in a life cycle perspective will be from 30 per cent to 90 per cent more expensive than conventional diesel technology, depending on different fuel delivery options (imported LNG, pipeline gas etc).

A DNV study of the future anticipated environmental requirements for ships have revealed that a fuel cell ship will see drastically reduced operating costs caused by introduction of incentive mechanisms for reducing emissions to air. An estimate was done for year 2015 for a ship in European waters. Owing to anticipated reduced environmental fees and introduction of trading of emission quotas, the lower operational costs will more than compensate for the higher installed costs of fuel cells. Comparing fuel cells with traditional exhaust cleaning technologies, rough analysis of costs indicates that fuel cells are from zero to 50 per cent more expensive than such arrangements today.

Conclusions
Fuel cell technology is becoming relevant and available for industrial purposes. Ships represent an appealing market for making use of the benefits offered, seen both from the operator point of view and from the society. The project partners believe this will benefit future business developments for the partners in their respective fields, and R&D within applied fuel cell technology in general.