An engineering prototype Bentley Flying Spur Hybrid has completed a 733km drive, taking the car across Iceland in a single stint entirely on renewable power.

The feat was performed using only energy from waste straw and geothermally-sourced electricity available from the Icelandic power grid, and validates both grand touring range of Bentley's new hybrid and of Bentley's research into biofuels that can be used without engine modification.

The fuel in question is a second generation biofuel developed by Coryton. It is produced by using waste biomass such as straw and breaking it down via fermentation, leading to the creation of ethanol. Dehydration of the ethanol converts it to ethylene, which can then be transformed into gasoline through the process of oligomerisation.

The fuel used conforms to the same EN228 standard as ordinary pump gasoline, and is claimed to be produced at no cost to food production or the natural ecosystem. The combination of this fuel and the Flying Spur Hybrid's intelligent electrified powertrain meant an overall reduction of 45% in CO2 emissions on a well-to-wheels basis over the course of the adventure.

The electricity used by the car's hybrid system during the journey meanwhile was sourced from Iceland's 100% renewable grid. Iceland is a global leader in renewable energy production, with 75% of the country's electrical energy being hydroelectric and the remaining 25% from geothermal power. During its time in Iceland, the Flying Spur Hybrid was charged with electricity from the Svartsengi geothermal power plant.