With demand for offshore support vessels set to soar by almost $10bn between 2020 and 2028 – a large part of it to support massive global offshore wind growth – shipbuilders and operators face a major challenge to not only design OSVs that can meet increasingly complex requirements, but to do so in a way that is sustainable.

The International Maritime Organization (IMO) is currently considering new regulations on emissions from shipping that would widen the current focus of the rules to cover the entire lifecycle of a fuel, with the aim of providing a more accurate assessment of carbon footprint.

Assuming the IMO’s lifecycle regulatory framework is implemented, it will drastically impact the fuel choices made by OSV operators, designers, owners, shipbuilders and charterers.

As the role of the OSV evolves from that of a simple platform supply vessel to multifaceted ships able to support wind turbine installations, crew transfers, multi-purpose supply operations and subsea mining, among other use cases, they will need to run on alternative fuels as part of the wider offshore movement to decarbonise.

The carbon footprints of each fleet will be different, and each ship will require a unique strategy to find the most effective path to compliance within the new regulations and emissions targets – but the big picture is that the OSV of the future is set to run on low- and zero-carbon fuels.

The fuels – or the energy and technologies needed to produce them – vary in their maturity of development. For example, LNG, methanol, offshore wind (for battery power) and biofuels are well-established, while the likes of ammonia, methanol and hydrogen are still in the nascent stages and some way off commercialisation in our sector.

While other technologies have inherent challenges, they could become more competitive over time if these are overcome. Examples include floating solar and even nuclear, the latter requiring significant government and private investment to feasibly become a reality.

In the shorter term, retrofitting OSVs with LNG and biofuels (both seen as good transitionary fuels) appears to be the most viable option. New vessels, on the other hand, could be designed to incorporate the likes of ammonia, methanol, hydrogen and fuel cells and represent more of a longer-term strategy that we expect to see investment into over the coming decades.

As marine and offshore transitions away from the combustion of hydrocarbons, fuel-cell technologies are drawing particularly careful attention from shipowners.

Consensus is building that the types of fuels currently being used in fuel-cell technology can be easily adapted to support maritime operations. These include methanol or methanol/water solutions (regardless of concentration) used to produce electricity, formic acid, hydrogen, methanol clathrate compound, borohydride compounds, and butane. Among these fuel sources, hydrogen, despite its lower energy content compared to conventional marine fuels, holds promise for the maritime sector’s energy transition.

ABS’ recent report on the future of OSVs also reveals how dual-fuel engine technology is also making the transition to alternative low- and zero-carbon fuels much easier – with some surprising sources for the energy needed.

Harvey Gulf International Marine announced in February 2022 that it has begun to operate one of its “tri-fuel” vessels exclusively on battery power and renewable liquefied natural gas (RLNG), with diesel fuel as backup. RLNG is recaptured swine and dairy farm gas from pigs and cows. Its use enables dual and tri-fueled RLNG vessels to be classed Carbon Neutral.

Wei Huang is director, global offshore market sector lead, offshore support vessels at ABS