Lufthansa will next Friday become the first airline to run regular commercial flights powered partially with biofuel.

Airlines have flown many demonstration biofuel flights, but Lufthansa's LH013 11:15am Hamburg to Frankfurt flight will start the first passenger service to run on a blend of biofuel and conventional fuel.

The company will use the novel fuel mix for six months on eight of its 28 daily 50-minute flights between the two German cities – a distance of 244 miles each way. The German airline says the 1,200 flights will save 1,500 tonnes of CO₂.

Biofuels could help airlines reduce carbon emissions. However critics say that biofuels take up land for growing food and raise prices. Worse, if they promote deforestation, they can actually raise emissions.

"Our interest is to have sustainable resources in the future, to have an alternative to offer flights at affordable prices to everyone," Aage Dünhaupt, Lufthansa's director of corporate communications Europe, said.

One engine of the 200-seater Airbus A321 will be fed with a 50-50 mix of biofuel and conventional kerosene-based fuel, the other engine will run on kerosene alone. That will allow Lufthansa to compare the engines' performances under exactly the same conditions. It was not necessary to modify either engine.

The trial will be expensive. Dünhaupt said Lufthansa paid "more than double" the price of kerosene and is spending €6.6m on the flights, a "large percentage" of which is fuel.

The flights follow last Friday's approval of jet biofuels by ASTM, a standards body. ASTM limits the biofuel component in the fuel mix to 50%. One reason for this is that biofuels lack chemicals that prevent leaks. Biofuels also have a lower density than ASTM's minimum.