Commercial aircraft are a major contributor to greenhouse gas emissions, but manufacturers and operators are taking steps to tackle the problem. Operators such as Virgin Atlantic have conducted demonstration flights using biofuel, and now KLM Royal Dutch Airlines has completed its first ever passenger flight powered by sustainable kerosene. Using a 50 percent biokerosene/50 percent normal jet fuel mix to power one of its four engines, a Boeing 747 carrying 40 select passengers last week circled the Netherlands for an hour in what KLM claims is the first flight of its kind in Europe.

The green jet fuel used for the flight was converted from oil from camelina, an inedible plant, using a process originally developed in 2007 by UOP, a Honeywell subsidiary working under a contract from the U.S. Defense Advanced Research Projects Agency (DARPA) to produce renewable military jet fuel for the U.S. military. The process is based on hydroprocessing technology commonly used in today's refineries to produce transportation fuels. In this process, hydrogen is added to remove oxygen from natural oils produced from sustainable feedstocks including camelina, jatropha and algae.

The UOP process produces a green jet fuel that is blended seamlessly with petroleum-based fuel. When used in up to a 50 percent blend with petroleum-derived jet fuel, the green jet fuel is a drop-in replacement that requires no changes to the aircraft technology and meets all of the critical specifications for flight, including a freeze point at -47°C and a flash point at 38°C.

Biofuels have attracted much interest from all sectors of the transport industry, but some have questioned whether the direct cut in emissions offered by biofuels isn’t offset by the energy and land needed to grow biofuel crops. To address this concern the SkyEnergy consortium established by KLM and partners North Sea Petroleum and Spring Associates will rely on the World Wide Fund for Nature (WWF) for advice in relation to the ecological aspects of biofuel production.

As camelina, the biofeedstock that was converted to make the green jet fuel, is an inedible plant that grows in conditions where other food crops cannot, it is considered a sustainable, second-generation resource because its cultivation and harvesting do not tax valuable food, land or water resources.

“The food chain may not be jeopardized, and production of biokerosene should not go hand in hand with deforestation or excessive water consumption,” said KLM President and CEO Peter Hartman, adding: “The conservation of biodiversity is, of course, also a precondition. Our cooperation with WWF is both important and inspirational.”