by Paul Pryce. With degrees in political science from both sides of the pond, Paul Pryce has previously worked as Senior Research Fellow for the Atlantic Council of Canada’s Canadian Armed Forces program, as a Research Fellow for the OSCE Parliamentary Assembly, and as an Associate Fellow at the Latvian Institute of International Affairs. He has also served as an infantryman in the Canadian Forces.
The USS Texas, commissioned in 1914, was the last American warship built with coal-fired burners. In 1925, it was converted to burn fuel oil, drastically improving its efficiency and bringing about the end of the “age of steam”. Interestingly, just 60 years before the refit of the USS Texas, the US Congress commissioned a study in 1866 to determine whether fuel oil would be a viable replacement to coal. That study concluded that the only advantage to such a transition “…was a not very important reduction in the bulk and weight of fuel carried”. In hindsight, the switch from coal to fuel oil by navies the world over would seem inevitable, given the quite important reduction in bulk and weight, the lower carbon emissions profile of fuel oil, and numerous other factors. However, the early rejection of fuel oil is worth reflecting on, given new regulations introduced by the International Maritime Organization (IMO) regarding sulphur oxide emissions.
In 2018, the IMO member states agreed to further restrict the sulphur content of bunker fuel from 3.5% to 0.5% by 1 January 2020. This might be accomplished through a variety of means, including the development of new blended fuels, which combine heavy fuel oil with a gas oil to lower the sulphur content, or the installation of “scrubbers”, which are exhaust gas cleaning systems. However, some countries, such as Japan, have begun to explore whether the time has come for new marine fuels – specifically liquefied natural gas (LNG), liquefied petroleum gas (LPG), or hydrogen. The technology is not that far off: Equinor, a Norwegian state-owned enterprise, is expected to launch its fleet of very large gas carriers (VLGCs) powered by LPG in late 2020.
Although US policymakers are reportedly considering ways of opting out of or otherwise disrupting the new IMO regulations, it is certainly worthwhile considering what capabilities the US Navy might gain from leaning into this technological change in the way that private industry has. LPG, LNG, and hydrogen would enjoy weight advantages over fuel oil, allowing for vessels to operate without refueling for even more extended periods of time or affording space aboard for other mission-relevant payloads. Since 2016, General Motors, the Office of Naval Research, and the US Naval Research Laboratory have partnered on a research project regarding unmanned undersea vehicles (UUVs) using hydrogen fuel cell technology (see photo on the right), with the higher efficiency of hydrogen intended to allow these vessels to conduct surveillance for vastly longer periods of time than would be possible with conventional fuels. LPG prices are also considerably lower than diesel or LNG in the US and elsewhere.
However, it is difficult to say how military vessels using such alternative fuels would perform in combat. In recent years, there have been several incidents involving LPG tankers that resulted in the loss of life. In January 2019, two Tanzanian-flagged LPG tankers collided in the Kerch Strait – a disputed waterway that links the Black Sea and the Sea of Azov – leading to an explosion aboard one of the vessels that killed 11. At least one of the two tankers had reportedly failed safety inspections, with corrosion rife on her bulkheads and decks. In September 2018, a tanker truck transporting LPG exploded in Nigeria’s Nasarawa state, killing 35 people. LNG cannot burn in its cryogenic liquid form, which could give some momentum toward the use of LNG as an alternative marine fuel. However, the new interest in transitioning commercial power generation from coal to natural gas could drive LNG prices globally to levels unattractive to most militaries. The safety concerns presented by LPG and by hydrogen could, therefore, become an obstacle to their adoption by naval forces until designs can be presented, which demonstrate the survivability of vessels powered by such fuels.
Evidently, the new IMO regulations present a challenge to the US Navy and other naval forces around the world. Ports, such as Los Angeles and Long Beach, have introduced Clean Air Action Plans (CAAPs), intended to incentivize ships docking at their facilities to lower their emissions. In the near future, such ports might refuse vessels that do not comply with their emissions requirements. This would certainly constrain American power projection, were US Navy vessels to be prevented from accessing strategic ports due to the Navy’s continued use of heavy fuel oil. Unlike in 1866, the US Navy cannot afford to wait another 60 years before making the jump to a new fuel.