The current initial collaboration, expected to end in 2016, also encompasses the delivery of larger batches that will allow Audi to run comprehensive engine testing and thus validate the specifications of Global Bioenergies’ isooctane. Global Bioenergies will use its demo plant, presently under construction on the site of the Leuna refinery, to produce these batches.

The now-signed extension and enhancement of the collaboration agreement between the two focuses on making Global Bioenergies’ technology accessible for non-biomass-derived carbon sources such as CO₂ or CO and energy sources such as green hydrogen produced from wind or solar energy. (Earlier post.)

The two principal next steps we see on the path towards commercialization of Audi e-benzin consist in upscaling Global Bioenergies’ technology towards the demonstration scale, which is on its way in Leuna, as well as ensuring the technology can work with non-biomass derived feedstock according to Audi’s e-fuel strategy.

—Reiner Mangold, Head of sustainable product development at Audi

The underlying principle of Audi e-fuels is to use CO₂ as a raw material in fuel production and incorporate it into a closed carbon cycle.

Isobutene is a four-carbon branched alkene and one of four isomers of butylene (C₄H₈); isobutene dimerization (putting two isobutene molecules together) and subsequent hydrogenation produces the eight-carbon molecule isooctane (C₈H₁₈).

Pure isooctane (2,2,4 trimethylpentane) has both a high research octane number (RON) and a high motor octane number (MON): 100 RON and 100 MON. A low Reid vapor pressure of 1.8 psi make it also attractive for bending into reformulated gasoline. As a 100% drop-in fuel, isooctane can be used in any blending ratio with all standard fuels for gasoline motors.

However, Global Bioenergies’s current production pathway for bio-isobutene—fermenting sugars derived from starch or biomass—doesn’t mesh with Audi’s ideal e-fuels criteria: water, CO₂ and renewable energy. Thus, the two companies have been working on a technology allowing the production of renewable isooctane not derived from biomass sources. (Earlier post.)

Isooctane is a premium gasoline, displaying both a high octane rating and a low volatility. Targeting its large scale production will benefit from extending our process compatibility to various feedstocks that do not compete with neither the food nor the feed production.

—Marc Delcourt, CEO at Global Bioenergies

This new agreement includes the payment of upfront and milestone fees, as well as the possibility for Audi to acquire shares of Global Bioenergies corresponding to less than 1% of its capital.