Ideas new and old for meeting the challenge of sustainable shipping
Even before “IMO 2020” came into effect on January 1st 2020, the quest to find the “next” fuel to power line haul size vessels was underway. But IMO 2020 kicked the process into high gear. With environmental concerns paramount in the design process, innovations in power plants and fuels have gone from the planning to prototype to mainstream at breakneck speed.
Dubbed “IMO 2020,” the new rule limits the amount of sulphur in the fuel oil used on board ships operating outside designated emission control areas (ECAs) to 0.50% m/m (mass by mass). This represents a significant reduction from the previous limit of 3.5%. Within specific designated ECAs the limits were already stricter at 0.10%. This new limit was made compulsory following an amendment to Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL).
In order to meet these new standards many shipowners retro-fitted scrubbers to remove sulphur oxides from the ship’s engine and boiler exhaust gases. This eliminated the need to find a fuel compliant with the IMO 2020 regulations. A ship fitted with a scrubber could use heavy fuel oil, as the sulphur oxides emissions are reduced to a level equivalent to the required IMO fuel oil sulphur limit.
However, while scrubbers worked, they were in many respects a Band-Aid solution. And didn’t address the more profound problem of making ships more environmentally sound even beyond the IMO 2020 protocols. This meant taking a whole new approach to powering vessels by finding a substitute fuel for a technology that has been in place for a century.
But what are the practical alternatives to fuel oil? This isn’t a new problem. Ship designers have been looking for new fuels for ships for decades. The nuclear powered NSS Savannah built in 1959 was an attempt to look at an alternative future for commercial use. The concept behind the ship’s construction was to find non-military uses for nuclear power. Though the ship sailed over 450,000 miles before retirement, nuclear power was never considered a viable option for merchant ships.
But the idea of finding a fuel with little or no polluting exhaust yet capable of powering large commercial vessels has become a holy grail of marine engineering. In a sense, this is a two-fold challenge, the first designing and building a practical powerplant of sufficient strength to propel a ship through its normal sea routes and secondly to build an infrastructure to support the ship’s refueling. With 2030 IMO deadline now looming on the 40% reduction in carbon emissions, finding alternatives…
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