NASA Study Confirms Biofuels Reduce Jet Engine Pollution

A NASA research study revealed that using biofuels to power jet engines reduces particle emissions in their exhaust by as much as 50 to 70%. The findings were the result of a cooperative research program led by NASA and involving agencies from Germany and Canada.

Contrails are produced by hot aircraft engine exhaust mixing with the cold air at cruise altitudes above Earth's surface, and are composed primarily of water in the form of ice crystals. Researchers were interested in persistent contrails because they create clouds that would not normally form in the atmosphere, and are a factor in influencing Earth's environment.

The tests involved flying NASA's DC-8 as high as 40,000 feet while its four engines burned a 50-50 blend of aviation fuel and a renewable alternative fuel from camelina plant. A trio of research aircraft took turns flying behind the DC-8 to take measurements of emissions and contrail formation.

Data on the effects of alternative fuels on engine performance, emissions and aircraft-generated contrails at altitudes flown by commercial airliners was collected during flight tests from 2013 to 2014 near NASA's Armstrong Flight Research Center in Edwards, California.

Researchers now plan to continue these studies to understand and demonstrate the potential benefits of replacing fossil fuels with biofuels in aircraft.