Ocean Shipping Alternative Fuels Studied
Methanol and ethanol are good potential alternatives for reducing both the emissions and carbon footprint of ship operations.
So concludes a recently-released report prepared for the European Maritime Safety Agency (EMSA).
EMSA commissioned a study to gain more information about the benefits and challenges associated with these fuels and to evaluate their potential for the shipping industry.
Methanol has been investigated as a marine fuel in a few research projects, two of which involved pilot test installations on ships. The Swedish EffShip project identified methanol as a promising marine fuel after studying alternatives and carrying out laboratory testing on a diesel concept engine. This led to further testing and development within the SPIRETH project, which led to the world’s first methanol conversion of main engines on a passenger ferry, the Stena Germanica, in 2015.
Waterfront Shipping has commissioned seven new chemical tankers with dual fuel methanol engines to be delivered in 2016. New research projects underway or recently started include the EU Horizon 2020 project LeanShips, which includes a work package to test a marine methanol engine in a laboratory.
Ethanol has not been studied for use on ships, but it has been used in truck diesel engines for years.
Methanol is the simplest of alcohols and can be produced from many different feedstocks, with the majority produced from natural gas. Ethanol is mainly produced from biomass, with the majority on the world market produced from corn and sugar cane.
Both methanol and ethanol have about half of the energy density of conventional fossil fuels, which means that more fuel storage space will be required on board a vessel as compared to conventional fuels.
The flashpoints of both substances are both below the minimum for maritime fuels specified in the International Maritime Organizations (IMO) Safety of Life at Sea Convention (SOLAS). That means that they must be evaluated for the fire safety equivalence to conventional fuels, the report noted.
Guidelines are currently being drafted for the use of methanol and ethanol fuels on ships, for future
incorporation in a newly-adopted international code for ships using non-conventional fuels.
“This,” the report noted, “will facilitate the use of these fuels on board ships.”
Earlier projects both carried out risk assessments and were approved for installation, “demonstrating,” the report concluded, “that safety considerations are not a barrier to the use of methanol fuel systems on ships.”
Methanol and ethanol both have environmental advantages compared to conventional fuels: they are clean-burning, contain no sulfur, and can be produced from renewable feedstocks. Emissions are low compared to conventional fuel oils.
Both methanol and ethanol dissolve readily in water, are biodegradable, and do not bioaccumulate, meaning they pose less of a threat than fossil fuels when discharged into the maritime environement. They are also not considered to be toxic to ocean life.
Since the recent oil price declines, and until early 2015, methanol was more expensive than fossil fuels, but in late 2015 the price of methanol began to move down. “Cheap natural gas, a primary feedstock for producing methanol, contributes to lower production costs,” the report noted, “and thus methanol may be economically attractive again compared to conventional fuel alternatives.”
Ethanol prices have generally been higher conventional fuels.
Investment costs for methanol and ethanol retrofit and newbuild activity are estimated
to be below the costs of investments for liquefied natural gas solutions.
“The payback time analysis carried out for this study indicate that methanol is competitive with other fuels and emissions compliance strategies,” the report concluded, “ but this depends on the fuel price differentials. Based on historic price differentials, methanol will have shorter payback times than both LNG and ethanol solutions for meeting sulfur emission control area requirements. With the current low oil prices at the end of 2015, the conventional fuel oil alternatives have shorter payback times.”
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