Green hydrogen in ocean-going shipping?in Trends by Andrew Craston
As the world struggles to conquer the coronavirus and overcome the catastrophic economic impact of the pandemic, there have been frequent calls for an environmentally sustainable economic recovery and no return to the status quo a priori. Could green hydrogen and fuel cell technology propel ocean-going shipping into a sustainable, economically viable future?
As long as our earth exists, water, wind, and sunlight will be abundantly available. These are the only resources required to produce green hydrogen through water electrolysis technology. This process breaks down water into hydrogen and oxygen. And if the electricity required for the electrolyser is from renewable sources, the hydrogen really is green. As an energy carrier, green hydrogen produced, for example, by means of thyssenkrupp’s large-scale water electrolysis technology, is an approved primary control reserve in Germany. In practical terms, this means that electrolysis plants can act as large-scale buffers to offset short-term fluctuations in renewable power generation. Yet green hydrogen is not only a clean energy carrier but also a fuel for a sustainable future in shipping as hydrogen can be easily converted into electricity in a fuel cell.
Fuel cell technology
In a fuel cell, hydrogen and oxygen are combined to generate electricity, heat, and water by means of an electrochemical reaction. A typical fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. A catalyst splits the hydrogen molecules into electrons and protons at the anode. The protons pass through the porous electrolyte membrane, while the electrons are forced through a circuit, generating an electric current and excess heat. At the cathode, the protons, electrons, and oxygen combine to produce water molecules. As there are no moving parts, fuel cell systems are clean and quiet. The technology has advanced a lot since William Grove invented the first fuel cell in 1838 and is now an efficient, reliable means of generating electricity.
An individual fuel cell only generates around 1.2 volts – not much more than a small torch battery. But fuel cells can be stacked on top of each other to generate higher voltages. A fuel cell stack composed of around 4,000 individual cells will deliver 80 KW of drive. Yet despite the technical challenges of scaling up the technology, fuel cells have great propulsion potential for ships and boats, as they are an entirely emission-free power source – a key advantage for ocean-going shipping. As the commonly used 3.5% sulphur bunker oil and even very low sulphur fuel oil (0.5% VLSFO) can hardly be described as environment-friendly, fuel cell drive systems powered by green hydrogen would be one way to significantly improve shipping’s environmental footprint.
Germany is one of the countries where green hydrogen technology has progressed furthest. It is not just that thyssenkrupp is the world’s No. 1 supplier of world-scale water electrolysis plants and equipment based on its proprietary advanced water electrolysis technology. In Laage near Rostock, one of the main Baltic Sea ports, a pilot project was recently launched for a plant that will ultimately generate 300 metric tons of green hydrogen a year via water electrolysis technology. The operator claims it will be the biggest plant of its kind in Europe.
Offshore wind farms are an obvious source of green energy and a large-scale wind-to-hydrogen project on Germany’s windy northwest coastline, Westküste 100, has just received the required funding from Germany’s Ministry of Economic Affairs and Energy. The Westküste 100 project aims to research and develop a process for producing green hydrogen from offshore wind energy and put the resultant waste heat and oxygen to good use. “The project is unique because it uses offshore wind power for large-scale hydrogen production. Only offshore wind can provide such a reliable renewable source of green power for electrolysis,” says Volker Malmen, who manages the German operations of Ørsted, the world leader in offshore wind energy and the driving force behind this project.
Fuel cells in ships
In October 2019, Meyer Werft, one of the world’s leading cruise liner shipyards, announced that its LNG-powered cruise ship AIDAnova would be testing fuel-cell technology as a propulsion system in 2021. This is part of the Pa-X-ell2 research project in which eight partners are collaborating to develop a decentralised energy network and a hybrid energy system with a new generation of fuel cells suitable for deployment on ocean-going passenger ships. However, like so many plans at present, the economic impact of the corona crisis on cruise shipping and shipyards like Meyer Werft has left a question mark behind the timing of this pilot project.
Fit for the future
Several types of hydrogen-powered vessels have been in operation since 2000. Besides smallish passenger vessels such as the ALSTERWASSER ferry in Hamburg, the HYDROGENESIS ferry in Bristol or the NEMO H2 in Amsterdam, water taxis such as the DUFFY-HERRESTORFF and yachts such as the suitably named NO. 1, the first-ever fuel cell-powered yacht, one of the most interesting applications of fuel cell technology is to be found in Germany’s Type 212 submarines, which went into service in 2005. The HDW fuel cell technology installed in these and later submarine models is now the world leader in non-nuclear submarine propulsion systems. What’s more, early in 2020 Bill Gates was reported to have commissioned the world’s first hydrogen-powered superyacht. However, no fuel cells have been scaled for and used on large merchant vessels.
LNG or green hydrogen?
From a sustainability perspective LNG has often been seen as the ship propulsion system of the future. “But natural gas is only a transitional technology,” says Prof Gerd Hollback from Berlin Technical University’s Institute for Land- and Sea-Borne Transport. In his view, the future belongs to hydrogen and fuel cell technology. The Port of Rotterdam Authority was the first port to join the Hydrogen Council, a global association of companies seeking to stimulate the use of hydrogen. Allard Castelein, CEO of the Port of Rotterdam Authority, is unequivocal: “Hydrogen is the energy carrier of the 21st century.” Benoît Potier, CEO of Air Liquide and co-chairman of the Hydrogen Council, is equally sure: “Policymakers, the business sector and investors worldwide consider hydrogen development indispensable for the recovery from the current economic downturn following the pandemic.”