According to the International Maritime Organization (IMO), maritime transport accounts for three to four percent of global greenhouse gas emissions (GHG). Global regulations are being implemented to reduce that number, specifically addressing carbon dioxide with a goal of reducing emissions by 50 percent by 2050. The volumes of nitrogen oxide and sulfur dioxide emissions are another major concern and are also being addressed.
The IMO implemented new sulfur regulations in 2016, which went into effect this past year for larger commercial vessels. This has resulted in ultra-low sulfur diesel fuel becoming the standard in Europe, North America, and in environmentally sensitive areas.
Hydrogen is heralded as a key future alternative fuel and is the prime source of energy in virtually all fuels, whether fossil fuels or alternative energy sources like methanol. Currently, around 48 percent of the global hydrogen is produced from natural gas (NG), and almost 95 percent of production in the Americas is derived from NG. Dual-fuel engines can burn hydrogen as fuel and would have very low GHG emissions with almost no change in the maintenance schedule. However, in storage, hydrogen must be kept under pressure to increase the storage density and reduce storage tank size. Compressed hydrogen is typically stored between 350 to 700 bar. Using hydrogen would require significant changes in how vessels carry and take on fuel and, since the primary source of hydrogen is fossil fuels, we are still using dirty energy to make clean energy.
The IMO implemented new sulfur regulations in 2016, which went into effect this past year for larger commercial vessels.
Liquid natural gas (LNG) emits 25 percent less carbon dioxide than conventional fuels but is mostly methane. So, we must look at the actual life-cycle emissions, which include potential leakage during extraction, processing, and downstream emissions. “Methane slip” can create a situation where the lifecycle GHG emissions are greater than current marine gasoil (MGO), which begs the question: Does hydrogen or LNG solve the pollution problem or just move it around?
There’s a drive to look at ammonia-based fuels. For example, Wärtsilä is conducting experiments with ammonia as a blend with diesel or LNG or even potentially as a standalone fuel. An exciting feature of ammonia is that it releases no CO2 when burned as a fuel. Ammonia does produce toxins such as nitrogen oxide during the fuel cycle, but solutions are being proposed to make it a viable fuel resource. Expectations are to have the first operational field testing as early as 2023 or 2024 with a carbon-free vessel operating in northern Europe using ammonia-based fuels.
Alternative fuels are coming, and they’ll be accompanied by new regulations, training, construction methodologies, as well as new opportunities for shipbuilders and infrastructure developers. We look forward to a time when all we leave in our wake are fond memories.
This article originally ran in the June 2021 issue of Dockwalk.