NASA-Led Study Confirms that Aviation Biofuels Can Be a Boon for the Environment
by Alan Boyle (GeekWire/Yahoo!) A NASA-led study demonstrates that airplanes powered by biofuels can emit up to 70 percent less particulate pollution – providing a potential boost for technologies that are being pioneered at Seattle-Tacoma International Airport.
The study, published today (March 15, 2017) by the journal Nature, was conducted in the skies over NASA’s Armstrong Flight Research Center in California. But the findings could be applied at Sea-Tac, where the Port of Seattle, Alaska Airlines and Boeing are partnering to work toward having biofuel available for every flight.
NASA’s flight tests in 2013 and 2014 were part of a series of experiments known as the Alternative Fuel Effects on Contrails and Cruise Emissions Study, or ACCESS.
Researchers wanted to find out whether biofuels had an effect on the formation of contrails, the cloudy trails that are produced when the hot exhaust of a jet engine mixes with cold air at high altitudes. Persistent contrails can evolve into long-lived clouds that wouldn’t form otherwise, affecting atmospheric conditions.
The study determined that particle emissions were reduced by 50 to 70 percent at cruise conditions, compared with the emissions from straight Jet A fuel. The reduction was less pronounced at high-thrust settings than at low to medium thrust.
Bruce Anderson, ACCESS project scientist at NASA’s Langley Research Center, said soot emissions are a major determining factor for the formation of contrails and their properties.
“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 said. READ MORE and MORE (AutoBlog) and MORE (Biofuels Digest) and MORE (BBC) and MORE (CBC News) and MORE (Digital Trends) and MORE (Ars Technica) and MORE (NASA) and MORE (GreenAir Online) Abstract (Nature)
Excerpt from Biofuels Digest: … but radiative forcing can be a “force multiplier” when it comes to emissions, meaning that aircraft emissions count for anything between 1.2 and 4.7 times their actual weight. The most recent studies we’ve seen focus in on a 1.9 figure.
Accordingly, because of “contrail-induced cirrus clouds” and “the contribution of black carbon, organic and sulfate aerosols that may act as cloud condensation nuclei and ice nuclei”, aviation-related contributions to what is known as radiative forcing may increase to 3–4 times the year 2000 levels.
Double Up: the aviation carbon opportunity
And that means a double carbon bonanza for biofuels, where carbon is counted.
Impact? If fully accounted for, you could see a biofuel producer looking at making diesel or jet with the same technology — but having a potential double carbon credit. That helps under, say, Low Carbon Fuel Standards, where the carbon credit is directly related back to the emission reduction. Not helpful under the Renewable Fuel Standard, where a gallon is a gallon is a gallon — except there is the possibility that fuels that reduce carbon by, say, 25%, could if supplied into the aviation sector qualify for pricey advanced biofuels RINs (that require a 50% reduction in greenhouse gas emissions). READ MORE