Alaska Airlines’ first biofuel-powered flights took off yesterday, kicking off an expensive trial program designed to improve the airline’s environmental footprint. Passengers on the first two flights—which were to DC and Portland, respectively—received a “Welcome to Greener Skies” flier explaining the program, the Anchorage Daily News reports. The 75 trips will run on a blend of regular fuel and 20% biofuel made from cooking oil.
Biofuel has just as many carbon emissions as traditional jet fuel, but it’s considered “greener” because it’s produced from renewable resources. But it doesn’t come cheap—Alaska dropped $476,000 for 28,000 gallons, which amounts to $17 per gallon, six times the cost of normal jet fuel.