Flight test by Boeing's ecoDemonstrator 787 marks first-ever use of green diesel as an aviation biofuel
The 787's left engine is fuelled with the blended green diesel
Thu 4 Dec 2014 – Boeing yesterday conducted the first-ever flight using green diesel as a biofuel component. The blend of 15 per cent green diesel and 85 per cent conventional jet fuel was used in one engine of a 787 currently testing new technologies as part of Boeing’s ecoDemonstrator programme. The green diesel was made from vegetable oils, waste cooking oil and waste animal fats, and was supplied by Finnish company Neste Oil before being blended in the United States by aviation fuel supplier EPIC Aviation. Neste claims sustainably produced green diesel can reduce carbon emissions by 50 to 90 per cent compared to fossil fuel. Green diesel is currently undergoing industry and regulatory scrutiny before it can be certified for commercial flight use. Boeing believes the product could rapidly supply as much as one per cent of global jet fuel demand, a critical level that could see aviation biofuels accelerate in take-up.
Already widely used in ground transportation, Boeing researchers have found green diesel – also known as renewable diesel – is chemically similar to HEFA (hydroprocessed esters and fatty acids) aviation biofuel that was approved for commercial use by fuel standards body ASTM International in 2011. The product is chemically distinct from biodiesel used in ground transportation.
“The airplane performed as designed with the green diesel blend, just as it does with conventional jet fuel,” reported Boeing Test and Evaluation Chief Pilot Capt Mike Carriker. “This is exactly what we want to see in flight tests with a new type of fuel.”
As an established fuel produced in high volumes, Boeing says the wholesale cost of green diesel is about $3 per gallon, inclusive of US government incentives. Not long ago, jet fuel prices stood at around this level, although the current dramatic fall in oil prices has brought jet fuel down to an average $2.21 per gallon. To supply one per cent of global jet demand would require a production capacity of 800 million gallons (3 million litres), says Boeing.
“Green diesel offers a tremendous opportunity to make sustainable aviation biofuel more available and more affordable for our customers,” said Julie Felgar, Managing Director of Environmental Strategy and Integration at Boeing. “We will provide data from several ecoDemonstrator flights to support efforts to approve this fuel for commercial aviation and help meet our industry’s environmental goals.”
The biofuel supplied by Neste Oil for Boeing’s testing purposes is the company’s regular winter-grade NEXBTL diesel fuel that is normally used in road vehicles. NEXBTL has already been used on nearly 1,200 regular commercial flights conducted by Lufthansa in 2012 but the fuel in this case was specifically manufactured as aviation fuel.
“Aviation is one of our target markets, and we were happy to be involved in this test,” said Kaisa Hietala, Neste Oil’s EVP Renewable Products. “The objective is that low blends of high-quality renewable diesel will be used in aviation fuels in the future.”
Green diesel is among more than 25 new technologies being tested under the current ecoDemonstrator 787 programme (see article). These include atmospheric observation equipment as part of a Japanese project called CONTRAIL (Comprehensive Observation Network for Trace gases by Airliners) involving Japan Airlines and environmental research and meteorological organisations.
The project has been ongoing since 1993 in which JAL’s aircraft have been fitted with sensors to gather greenhouse gas information in flight. As well as CO2 continuous measuring and air sampling equipment, the 787 ecoDemonstrator has been fitted with new equipment that also measures methane. The gathered information will be used by researchers studying the mechanism of global greenhouse gas circulation.
