Biofuel-powered jet engines could help reduce particle emissions in plane exhaust by as much as 70%, a new NASA-lead study has found.
According to the study, published in the Nature journal, test flights performed by NASA between 2013 and 2014 confirmed that particle emissions from jet engines were reduced by 50-70%, the space agency said in a 15 March statement.
The test flights near NASA’s Armstrong Flight Research Center in Edwards, California, were flown on a DC-8 aircraft at heights up to 12km, using a 50/50 blend of fossil aviation fuel and a camelina plant oil-based renewable alternative jet fuel.
A trio of other research aircrafts trailed the DC-8 at varying distances, collecting data on the effects of the biofuel on engine performance, emissions and aircraft-generated contrails as part of NASA’s Alternative Fuel Effect on Contrails and Cruise Emissions Study (ACCESS).
“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,” Rich Moore, lead author of the Nature study said in the statement.
The researchers were particularly interested in observing the camelina biofuel’s effect on the formation of contrails, short for concentration trails produced by hot aircraft engine exhaust mixing with the cold air found at commercial aircraft cruising altitudes.
Contrails were mostly composed of ice crystals and they could create long lasting and sometimes extensive clouds that would not normally form in the atmosphere.
According to NASA, contrails and the clouds that evolve from them had a larger impact on the Earth’s atmosphere than all aviation-related CO2 emissions since the Wright Brothers’ first flight.
“The observed particle reduction we’ve measured during ACCESS should directly translate into reduced ice crystal concentrations in contrails, which in turn should help minimise their impact on Earth’s environment,” summarised Bruce Anderson, ACCESS project scientist at NASA’s Langley Research Center in Hampton, Virginia, USA.