Zero emission ships may soon sail the seven seas, with the successful trial of the hydrogen fuel cell powered Viking Lady as part of the Norwegian FellowSHIP project. Ships powered by this technology has the clear advantage of emitting no NOx, SOx and particulate matter, and depending on how the hydrogen is produced, significant or complete reduction in CO2 emissions. However, at current level of development, it is still facing challenges in cost and weight which have to be managed before achieving commercial viability. Read more
Hydrogen fuels cells the future maritime fuel
From Ctech (23 September 2012):
Wide spread use of hydrogen fuel cell technology is still some way off in the international maritime industry.
However as recent success on the Viking Lady as part of the Norwegian FellowSHIP project showed, there is the real potential for application in large scale commercial maritime operations.
Additionally, two further hydrogen fuel cell powered concept vessels have been released. Fathom has taken a look at what the state of play is for hydrogen fuel cell technology and when it might see wide spread application.
There are clear advantages to the technology including the elimination of NOx, SOx and particulate matter. Dependent on how the hydrogen is produced there is also a significant or complete reduction in CO2 emissions.
Additionally the technology is associated with insignificant noise and vibration levels and lower maintenance levels as compared to traditional combustion engines; certainly an advantage for ferry and cruise ship applications.
However, challenges remain with a real need to decrease investment costs, improve service lifetime, and reduce the current size and weight of fuel cell installations before the technology could really be considered truly commercially viable.
Costs of installation
Fuel cell prices vary significantly between different fuel cell technologies and it is expected that investment costs will never compete directly with combustion engines (rather the lifetime costs installation and operation) must be considered.
At the current time installation costs of a combustion engine are in the region of 3-400$/kW. For fuel cells, lowest installation costs at the current time have been estimated in the region of $3000$/kW. A target goal of $1,500$/kW is cited as the development goal for commercialisation of fuel cells (Excombe 2008). Fuel cell producers estimate that this will be achieved between 2020 and 2025.
Cost of Operation
Whilst the daily maintenance requirements for fuel cells are minimal, stack replacement is necessary due to performance degradation. Fuel cell lifetime is gradually increasing with a goal of fuel stack replacement every five years whilst the remaining balance of the plant will typically have a 20-year lifetime.
What is Hydrogen Fuel Cell Technology?
Basic Principles of Fuel Cell Technology courtesy of Fuel Cell Today.
The Fuel cell power pack consists of a fuel and gas processing system and then a stack of fuel cells that convert the chemical energy of the fuel to electric power through electrochemical reactions. The process can be thought of as similar to that of a battery.
There are several types of fuel cells all requiring either pure hydrogen or fuel that can be converted to hydrogen and CO either prior to entering the fuel cell or inside the fuel cell itself. In the short-term therefore, options are restricted to fuels such as methanol or LNG.
There are also projects looking at whether marine diesel oil or heavy fuel oil could be converted although thus far these have proved unsuccessful.
Fuel Cell Technology on Ships
Although fuel cell technology is not new, and has been tested before on ships, the first large-scale fuel cell installation operating on board a merchant ship was carried out as part of the FellowSHIP Project.
The FellowSHIP project was led by DNV in conjunction with Eidesvik Offshore and Wärtsilä and MTU Onsite Energy.
For the project, a 330 kW fuel cell was successfully installed on board the Ediesvik offshore supply vessel, Viking Lady, and was in operation for more than 7000 hours.
A molten carbonate fuel cell (MCFC) was used that had been successfully demonstrated in several land-based installations. The technology, originally developed by MTU in Germany, was modified by the FellowSHIP project for operation in a marine environment.
The Viking Lady already uses LNG as the main fuel in the gas-electric propulsion system of Viking Lady meaning no additional fuel system was required to support the MCFC.
The ship’s electric propulsion system consumes fuel cell power equivalently to power provided by the main generators.
Although exact measurements of gas to grid efficiency were not possible, it was estimated to be 48.5% including internal consumption and 44.5% when DC/AC conversion was also counted for. A heat exchanger trialled increased the overall fuel efficiency to just above 55%.
The conclusions from the project were that with optimal system integration there would be the potential for increasing the electrical efficiency to close to 50% and the fuel efficiency up to 60%.
Hydrogen fuelled Zero Emissions Ship
However a vision for a zero emissions container feeder vessel was recently put forward by Germanischer Lloyd (GL).
The concept container vessel is envisaged as a full open-top 100TEU intake vessel with 150 reefer slots and a service speed of 15 knots.
There are two 5MW fuel cell systems with 3MWH battery systems to provide peak power.
It has special tanks for holding liquid hydrogen and stops every 10 days at an offshore station for bunkering.
The liquid hydrogen (LH2) used for fuel would be produced using surplus wind energy at the offshore station.
Two recently opened plants in Germany have already have demonstrated using hydrogen to store surplus wind energy is viable technology. The plants, now in operation for the better part of a year, use wind energy to generate Hydrogen through electrolysis.
The hydrogen form one plant is currently used to power vehicles and the other is fed directly in to the natural gas pipeline system
GL say that investment costs for the LH2-fuelled container feeder vessel are about 30% higher than for a conventional vessel.
They predict that the LH2-fuelled vessel may become economically attractive when MGO prices increase beyond 2.000 $/t.
A further hydrogen concept ship has been developed by FutureShip, GL’s consulting subsidiary, with a view to the strict limits in sulphur emissions due to come in into effect in 2015 in the Baltic Sea.
They have been working with ferry owner and operator Scandlines to help them develop a fuel-cell-driven concept design with for their Baltic ferry lines.
The resultant design is for a double-ended ferry for with space for 1,500 passengers and 2,200 lane-meters for vehicles. Located on deck, the hydrogen tanks can accommodate 140 m3—enough for a passage of 48 hours.
The fuel cells offer a rated power of 8,300 kW and the storage batteries a capacity of 2,400 kWh. The nominal speed of the ferries is set at 17 knots—the parameter used for sizing the fuel cells. To accelerate up to 18 knots, the four 3 MW pod drives draw additional current from the batteries. Flettner rotors on deck add to the energy efficiency of the design.
One of the main barriers to use of hydrogen fuel cells is the high cost, however the project above is proposed as a ‘cheaper’ alternative- not to other types of ships though but to a road transportation project.
There is currently a huge infrastructure project between Germany and Scandinavian countries (the Fehmarn Belt tunnel) which has been delayed since it was launched in 2010-2011.
It will link Germany and West Danish Islands which will create a shortcut to reach the Copenhagen Area and Sweden and is exaclty where Scandlines is currently operating its most profitable route.
The Scandlines proposition is for four of the ‘zero emission’ ferries that would provide an alternative by not only coping with the increasing traffic, but offering a more environmentally beneficial solution. Importantly the ferry alternative is projected to be significantly cheaper (gross cost of around 500M€ as opposed to 6Bn€).
At the current time however, it is only such specific projects that may be economically viable. Even the FellowSHip project recognise that it will take some time before fuel cells can become realistic on-board alternatives.
Nonetheless, it has been proved that the technology is viable and once that hurdle has been passed, it is usually only a matter of time until commercially cost viable products are launched.