German airline Lufthansa ended its six-month trial of biosynthetic kerosene with a transatlantic test flight on Thursday.

The Boeing 747-400 left Frankfurt for Washington DC carrying around 40 tons of a biosynthetic fuel mix. The company said the alternative fuel would reduce the flight's carbon footprint by 38 tons – the same amount emitted by six connections between Frankfurt and Berlin.

The long-haul trial was the final test in a program that saw Lufthansa operate 1,187 domestic flights between Frankfurt and Hamburg using a 50/50 blend of regular fuel and bio-kerosene in one of the plane's two engines. The result was a total saving of about 1,500 tons of CO2.

Not so fast

The airline's vice-president in charge of the biofuel project, Joachim Buse, said the trial produced "a positive result from which we want to continue to work."

But he added that Lufthansa would not make regular use of the biofuel, which was made using Jatropha plants grown in Indonesia, until global production increased to a level that could support routine operations.

"As a next step, we will focus on the suitability, availability, sustainability and certification of raw materials," Buse said in a conference call.

"The objective is to arrive at a price on the basis of which we can work," he added.

Arne Roth from the Munich-based aviation think-tank Bauhaus Luftfahrt said that even if Lufthansa could secure large volumes of biomass, expanding the supply chain downstream would be very difficult.

"Right now there just aren't enough refineries capable of producing this type of fuel," Roth told Deutsche Welle. "These facilities are quite different from the refineries that produce biodiesel."

Food for thought

Airlines have been racing to cut carbon dioxide emissions since the European Union announced it would include the aviation industry in its Emissions Trading Scheme starting this year.

Lufthansa said its biosynthetic kerosene emitted about 50 percent less CO2 than regular fuel, but many environmental groups remain wary of biofuels in general because some sources, such as palm oil, use land that could have be used to grow crops to feed people instead.

"The problem is there's a global shortage of agricultural land," said Gesche Jürgens from Greenpeace.

"We need to decide whether we want to use that land to produce biofuel or food. If we choose food, then any biofuel production on top of that would require additional land. That normally means clearing a forest somewhere, so nature pays the price."

Business-class greenwash

Jürgen Schmid from the Fraunhofer Institute for Wind Energy and Energy System Technology agreed and described the biofuel trend as environmental "window-dressing."

Although biofuels were suitable for small-scale application such as heating homes, they were a poor choice for powering vehicles and aircraft, he said.

"If you use biomass to produce fuel, you only get about 50 percent of the total energy contained in that material. The rest is lost in the production process, which is very complex and expensive," Schmid said.

He added that the vast areas of land needed to grow fuel crops meant "using conventional fuel would be more environmentally friendly."

Algae solution

Lufthansa may have found a solution to the food versus fuel debate, however.

Last month, Australian company Algae.Tec announced it signed a memorandum of understanding with the German carrier to jointly assess the fuel-making potential of oil extracted from algae grown in bio-reactors.

Other non-plant-based options for creating next-generation biofuels are also in the works. News agency Reuters reports British Airways plans to start powering its fleet with a fuel refined from waste by 2015. Rival carrier Virgin Atlantic intends to start using a waste gases-derived fuel by 2014.

Authors: Andreas Becker, Sam Edmonds
Editor: Andreas Illmer