In order to reduce GHG emissions from ships, researchers from the National Renewable Energy Laboratory (NREL) and other Department of Energy facilities are investigating the potential use of marine biofuels.
As Eric Tan, a senior research engineer at NREL explains, ”biofuels turned out to be very good options because they have zero or very, very low sulfur compared to fossil fuels”.
The NREL-directed research provides a starting point for establishing the feasibility of ships using biofuels. Fueling costs already account for a significant part of running a shipping line, so the researchers examined both prices and emissions.
The economics are weighed against the cost of burning heavy fuel oil (HFO), which accounts for about three-quarters of the fuel used by ships.
A low-sulfur HFO costs slightly more a gallon than traditional HFO. The low-sulfur HFO prices would be the maximum ship owners are willing to pay for biofuels for a one-to-one replacement. The biofuels are considered to be potential drop-in fuels compatible for use in marine engines, but further work is needed to confirm that compatibility
say the researchers.
What is more, upon examining different types of fuels for their ability to reduce emissions of greenhouse gases and air pollutants, the researchers discovered that biofuels produced entirely from biomass offer much higher reductions in life-cycle greenhouse gas emissions – from 67% to 93% less than HFO. Biomass-derived fuels also are mostly free of sulfur and exhibit reductions in criteria air pollutant emissions such as particulate matter.
The research also concluded that, if shipping had no competition, the US has a large supply of bio-feedstocks for producing substantial amounts of marine biofuels to displace fossil fuels. With ships using 400 million metric tons of fuel annually, a blend of 5% biofuels translates to about 5 billion gallons.
Recently, ABS also published a research on marine biofuels. In the report, ABS notes that biodiesels can be used in increasingly higher percentage blends to lower the emissions of marine vessels with little change to the vessel’s current operations. However, one of the current challenges of using drop-in fuels is their low availability and high cost of production.
