Press releases from the Federal Council
A prototype of a hydrogen river boat
High-tech propulsion for the next 100 years
Ecological fuels are not only interesting for cars: the University of Birmingham has been operating a river boat powered by a fuel cell for three years now. The principles applicable in shipbuilding are, however, different from those valid in automobile or aeronautical construction: there the weight plays practically no role but the lifespan of the engine must be equal to that of the boat itself. The hydride accumulator – in other words the hydrogen tank – for this high-tech long-term solution is an Empa development.
Boat is the most efficient mode of transport for goods. And yet this is precisely where many old diesel engines are still in use – without exhaust gas cleaning and modern electronics. Three years ago, the University of Birmingham launched an ambitious project: the transformation of an old river boat to hydrogen propulsion. Its diesel engine and fuel tank were removed and replaced with a high-efficiency electric motor, an electric storage battery for peak power and a fuel cell with a hydrogen accumulator to recharge the electric accumulators. In September 2007 the boat “Ross Barlow” set off on its first journey on the British river network which covers no less than 3,500 kilometers. Last year he completed his longest journey: in four days he covered 105 kilometers through no less than 58 locks – the time has come to take stock.
Standard propulsion combined with cutting-edge hydrogen storage technology
For the transformation of this steel boat with a length of 18 meters, it was first necessary to determine the power necessary for its propulsion. Based on the experience gained with other electric riverboats, the choice fell on a 10 kilowatt permanent magnet electric motor. The energy required for long journeys is provided by a fuel cell with a continuous power of 1 kilowatt, initially developed for the uninterrupted power supply of telephone networks. However, the power of the fuel cell is not enough to propel the boat. This is also why the “Ross Barlow” houses a 47 kWh buffer battery in its holds. For this battery, the choice fell on lead-acid accumulators which require little maintenance, are inexpensive and easy to charge. These lead batteries are certainly heavy, but weight plays almost no role in river navigation.
The hydrogen supply to the fuel cell is provided by a hydride accumulator, developed by Empa with financial support from the Federal Office of Energy (FOE), which is capable of storing 50 kWh of energy ; this capacity corresponds to 20 bottles of pressurized gas with a capacity of 10 liters. The material used for storing hydrogen is a powder made from an alloy of titanium, zirconium, manganese, vanadium and iron. This metal powder, enclosed in airtight steel tubes, is capable of storing hydrogen and releasing it when heated. This is also why each storage module is placed in a water tank which can be heated or cooled – because when “charging” the metal powder gives off heat. The boat is still equipped with photovoltaic cells which provide up to 320 Watt of electricity.
Charges and discharges – 100 years
Navigation on the canals with their locks requires electrical power which varies greatly. To protect the fuel cell, the engine draws its electricity from lead-acid batteries. A typical journey lasts four to six hours for which the boat consumes 12 to 18 kWh of power. The fuel cell provides 24 kWh of energy per day in constant operation. Since electronic control and monitoring systems also consume energy, approximately 19 kWh remains to recharge the buffer accumulators. – enough energy for a six-hour journey per day.
The durability and reliability of the metal hydride hydrogen accumulator were first tested in the laboratory. For the operation of the “Ross Barlow” this means that if it sails 650 kilometers per year on the English canals, it must be fueled 12 times per year with hydrogen. In this case, the lifespan of the hydride accumulator would exceed 100 years – much longer than the lifespan of the boat itself.
The results of the navigation test
During its 105 kilometer, four-day voyage last summer, the 'Ross Barlow' consumed 106 kWh – including power for lighting and charging the crew's mobile phones and laptops. The electric storage battery provided 71 percent of this energy, the fuel cell 25 percent and the photovoltaic cells 4 percent. The crew unanimously praised the virtually noise-free movement of the boat and the absence of unpleasant exhaust gases when passing through the locks. The comparably sized diesel-powered boat that accompanied the 'Ross Barlow' consumed 50 liters of diesel fuel, which corresponds to 133 kilograms of CO2 emissions. The CO2 emissions of the “Ross Barlow” are equal to zero, provided however that the hydrogen is produced from renewable resources and that it is transported without emissions to the banks of the canal to refuel the hydrogen boat.