Kia will roll out a liquefied-propane-gas version of its Picanto at the Frankfurt auto show next month, as it looks to meet what it says it growing customer demand for small cars with lower operating costs.

The new bi-fuel model is powered by a special version of Kia’s 1.0L 3-cyl. Kappa engine, producing 67 hp. It will be capable of 40.6 mpg (5.8 L/100 km) in LPG mode, but an optional stop/start system increases that to 42 mpg (5.6 L/100 km).

The Picanto LPG is fitted with two fuel tanks. A 9.3-gallon (35L) gasoline tank is installed ahead of the rear axle and a 7.1-gallon (27L) pressurized LPG tank is situated beneath the trunk floor in the space usually occupied by the spare tire. Drivers can switch fuel modes with the press of a button.

Initially, the bi-fuel model will be available in Germany, Italy, Poland, Czech Republic, Greece, Portugal and the Netherlands – where it is expected to account for up to 7% of Picanto sales.

When it goes on sale later this year, the left-hand-drive Picanto LPG will be the only LPG car in the market with a 7-year, 93,000-mile (150,000-km) warranty.