NREL and DOE researchers explore potential use of marine biofuels

In Colorado, a global effort to reduce sulfur and greenhouse gas (GHG) emissions from ships has researchers from the National Renewable Energy Laboratory (NREL) and other Department of Energy facilities investigating the potential use of marine biofuels. 

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.

Upon examining different types of fuels for their ability to reduce emissions of greenhouse gases and air pollutants, the researchers found 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 concluded that, if shipping had no competition, the United States 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.