A new study from NASA has shown that the jet engines using biofuels have fewer particle emissions in their exhaust trails.
In a news release earlier this week, NASA said the reduction could be "as much as 50 to 70 percent" and that the study bode well for both the environment and airline economics.
Data was gathered from test flights in 2013 and 2014, looking at the impact of alternative fuels on the performance of engines, emissions, and "aircraft-generated contrails" seen at altitudes that commercial airliners fly at. The tests were part of the Alternative Fuel Effects on Contrails and Cruise Emissions Study (ACCESS).
NASA described the contrails as being produced by the mixture of hot aircraft exhaust with cold air seen at cruising altitudes.
Persistent contrails were of interest, according to the agency, because they created "long-lasting, and sometimes extensive," clouds that would otherwise not form in the atmosphere. They were believed to be one factor impacting the environment.
The study involved flying three research aircraft, in turns, behind another plane that was using a 50-50 blend of aviation fuel and an alternative fuel produced from camelina plant oil.
"Soot emissions also are a major driver of contrail properties and their formation," Bruce Anderson, ACCESS project scientist at NASA's Langley Research Center in Hampton, Virginia, said.
"As a result, the observed particle reductions we've measured during ACCESS should directly translate into reduced ice crystal concentrations in contrails, which in turn should help minimize their impact on Earth's environment," Anderson added.
The findings were published in the journal Nature and were, NASA said, the result of an international research program led by NASA and involving bodies from Germany and Canada.
Rich Moore was lead author of the report in Nature. "This was the first time we have quantified the amount of soot particles emitted by jet engines while burning a 50-50 blend of biofuel in flight," he said.
