The City of Seattle is piloting renewable isobutanol blended with unleaded gasoline in its fleet vehicles to reduce greenhouse gas emissions. The city will use a blend of 20% Gevo renewable isobutanol with 80% gasoline to reduce carbon intensity levels, according to Philip Saunders, green fleet program manager for the City of Seattle. This blend lowers the carbon intensity of fuel from about 100 to 80.

“We have an executive order from our mayor to be fossil-fuel-free by 2030 so we are looking at 'cutting-edge' renewable alternatives that will help to reduce greenhouse gases for our fleet,” Saunders said.

The city will start with a three-month, five-vehicle pilot using light- and medium-duty vehicles. Saunders said the blend costs about $1.50 per gallon above the cost of conventional gasoline.

According to Gevo, Seattle has 4,100 fleet vehicles, 38% of which currently use gasoline.

The city is continuing to focus on electricvehicles; for vehicles that are unable to be electrified, renewable fuels will be a vital part in reaching the city’s greenhouse gas reduction goals. The fleet plans to expand the use of renewable diesel to all diesel vehicles soon.