Can the Lightest Element be a Heavy Hitter in the Fight to Decarbonize?

July 14, 2022

by Alice Brais

In an elegant plot twist, the key to resolving the energy crisis may lie with the most abundant element in the universe – hydrogen.

As several alternative marine fuels emerge to lead the green revolution, this diatomic gas is being hailed as the ultimate clean fuel.

Most impressive of its qualities is hydrogen’s potential to eliminate onboard greenhouse gas and air pollutant emissions. When consumed in a combustion engine or fuel cell, hydrogen reacts with oxygen to produce pure water. It doesn’t get better than that.

Plus, this promising gas has the best energy density by mass of all fuels and current battery technologies, bettering marine gasoil by a factor of nearly three, thus offering significant efficiency gains, ideal for remote and long-haul operations that aren’t easily electrified.

However, the advantages of hydrogen may be outweighed by its shortcomings. High fuel costs, exacerbated by a lack of large-scale production, transportation, and bunkering infrastructure, are a primary barrier to its widespread adoption as a marine fuel.

In truth, hydrogen does not exist in abundance in its pure form on Earth, and it must instead be produced from the splitting of hydrogen-carrying compounds. Natural gas is the primary feedstock for its production, accounting for 75 percent of today’s global supply. However, this approach does not necessarily yield reduced lifecycle emissions compared to burning fossil fuels. Although H2 emits no greenhouse gases when burned, the most prominent hydrogen production methods have huge carbon footprints.

Alternatively, hydrogen is produced emission-free by a renewable-powered process called electrolysis, which entails splitting water into its oxygen and hydrogen components. Accounting for only two percent of total hydrogen production, this method requires serious investment to satisfy industry demand and gain a cost advantage over conventional energy carriers.

The marine industry is also faced with mitigating the serious safety risks associated with the onboard use and storage of this volatile molecule, be it in high-pressure vessels or frigid cryogenic tanks.

The infamous Hindenburg disaster of 1937, in which a hydrogen-filled airship erupted into a fiery ball, killing 36 people, tainted the public’s perception of the buoyant gas. However, 85 years on, our understanding and treatment of hydrogen have dramatically improved. For the past few decades, NASA has invested heavily in hydrogen and fuel cells to power their rockets with great success, minus one incident involving a hydrogen fuel leak which ended with the crew safely returned home, albeit earlier than expected.

The maritime sector has been slower to embrace hydrogen. Yet, with several H2-fuelled vessels now in service and many more in the works, the IMO is developing rules that thoroughly address the risks and safety concerns of hydrogen as marine fuel. A few notable requirements included in the draft rulesets are the separation of hydrogen machinery and storage tanks from sources of ignition, routine purging of high-risk spaces and fuel lines, the use of gas detection and monitoring systems, and the integration of pressure-relief devices to protect against pressure buildup. Risk assessment and explosion analyses are also required for design approval.

With advances in technology and safety, the transportation industry is better equipped to embrace hydrogen, one of the few alternative fuels that burn without directly emitting carbon dioxide. While it is too early to predict which alternative fuel will dominate the marine industry, experts agree that electrolysis-derived hydrogen will play a vital role in the decarbonization of the global fleet.

With various hydrogen technologies now entering the maritime market, Robert Allan Ltd. is developing designs centred around this up-and-coming fuel, among other hydrogen carriers like methanol and ammonia, with encouraging results.