Hydrogen is the lightest and most abundant element in the universe. The power source that most stars burn to produce energy. First observed by Paracelsus around 1525 when experimenting with metals and acids. In 1766, Henry Cavendish isolated a gas 7-11 times lighter than air. Antoine Lavoisier named hydrogen in 1783, Greek for born of water (hydro = water, genes = born of).
Hydrogen technology is accountable for the production of ammonia and methanol. These two chemicals are the building blocks for numerous commodities and specialised chemicals through the processes of coking coal. We cannot mention hydrogen without talking about the progress in meteorology through the development of weather balloons from technology gained via the Zeppelin and the unfortunate Hindenburg disaster.
Furthermore, the rare isotopes of hydrogen are also important. NMR spectroscopy an essential analytical process used to determine the molecular structure and purity of the sample uses deuterated solvents. Tritium powers the radioluminescence in beta lights or night illumination exit signs and navigational compasses.
The 3 most common methods for producing and isolating large quantities of hydrogen gas are: –
• Steam reforming natural gas
CH4 (g) + H2O (g) (700–1100 °C)→ CO (g) + 3H2 (g)
• Coal gasification
C (s) + O2 (g) → CO2 (g) – combustion
C (s) + CO2 (g) → 2CO (g) – gasification
CO (g) + H2O (g) ↔ CO2 (g) + H2 (g) – water-gas-shift
• Electrolysis of water
2H2O (l) → 2H2 (g) + O2(g)
The first two methods create carbon dioxide and carbon monoxide as byproducts. 95% of global hydrogen is produced from the steam reforming method. However, electrolysis uses electricity to separate oxygen and hydrogen in water. This method is four times more expensive than coal gasification. Through electrolysis, it would be possible for ships to use the sea as their source of energy via hydrogen fuel cells.
Maritime transportation has an enormous impact on the environment. It contributes to oil spills at sea, acoustic nuisances and air pollution from diesel fuel. Also, water pollution via the incorrect discharge of bilge water, solid waste littering and shipwrecks. In the post How to leverage low air pollution post COVID-19, we discuss transportations impact on air pollution and our need to prioritise cleaner, low emission fuels with reduced particulate and sulphur content.
Transportation is a key hurdle in the race to reduce our fossil fuel dependency. We always hear about commercial aviation in the news. However, international shipping has a greater impact on global emissions. International shipping released 1,056 million tonnes of CO2 in 2018, this accounted for 2.89% of all global carbon dioxide gas emissions. If international shipping was a country, it would be the sixth biggest contributor to climate change.
Due to COVID-19, the emissions from aviation and international shipping will be tremendously reduced in 2020. The speed of economic recovery will affect how soon we return to 2018 emissions levels. The International Maritime Organization (IMO) set a 2050 goal for 50% of 2008 emissions (equivalent to 568 million tones of CO2). Several low/zero-emission fuel alternatives are being considered from biofuels to wind assistance, hydrogen, batteries, ammonia and electric ships. The potential to produce hydrogen from seawater is very promising. Let’s look at the hydrogen power options available for international shipping to assist with achieving this target.
Hydrogen Power in Ships
A study by U.S. Department of Energy’s Sandia National Laboratories looked at 14 vessels of varying size and routes from large cargo ships to small passenger ferries. As it takes years to fabricate new vessels and ships are built to last a long time. The researchers wanted to see if it was feasible to retrofit current ships for zero-emissions technologies. They compared battery to liquid hydrogen (LH2) and compressed/gaseous hydrogen (CH2).
The calculations found LH2 was the most practical, primarily because it took up the least amount of space. It is less dense than petroleum-based fuels. LH2 has a smaller fuel cell than CH2, therefore, requires less space. Overall, hydrogen fuel cells are more efficient than the internal combustion engine. Batteries were best suited for high power short duration routes. This study is a useful guide when deciding which zero-emission technology would suit a ship based on its size and energy requirements.
In Lyon, France a push-boat and Stavanger, Norway a passenger and car ferry are being constructed to run on hydrogen fuel cells. We look forward to seeing large long haul cargo ships being constructed with hydrogen fuel cell technology.
Hydrogen and Zero-Emission in Boats
The Energy Observer is the first boat to use hydrogen power as its primary source of energy. Created by Victorien Erussard, a merchant shipping officer and competitive sailor. The idea for this boat came to Victorien, during a transatlantic race when his diesel generator broke down leaving him in the middle of the Atlantic unable to power to his electronics and navigation. This drove Victorien to find a better way, in 2013, having acquired a racing maxi-catamaran which had participated in various races under many owners. Victorien, alongside a team of researchers and engineers, transformed this vessel into a floating laboratory. This self-sufficient boat can use solar, wind power and electrolysis hydrogen from seawater. In 2017, the Energy Observer set off on a voyage to travel the world on a continuous 6 years mission.
Solar panels charge the batteries during stopovers. When the batteries are full, the surplus solar power is used to produce hydrogen from the electrolysis of the seawater. The power consumption for propulsion, daily life on-board the boat and navigation share these renewable sources of energy. When the battery’s charge gets low, the fuel cell converts hydrogen power to electricity.
Zero Emission Shipping
The technology and research taking place on the Energy Observer will enable us to see how different renewable energy can work together to replace fossil fuels. Sandia National Laboratories guide is useful when deciding which zero-emission technology would suit a ship or route.
Overall, the goal is reducing the air emissions from particulate matter, carbon dioxide, oxides of nitrogen and sulphur. Water is an abundant source of hydrogen. With further research and development, the retrofitting of large sea vessels for fuel cells that convert hydrogen to electricity and produce hydrogen from the electrolysis of seawater will also assist to clean up the contents of the bilge water, air pollution and reduce oil spills from marine vessels.