Toyota and BMW are joining forces with energy giant Repsol and technology supplier Bosch for an unusual real-world experiment in Spain. Instead of testing another EV or hydrogen prototype, the companies are putting ordinary gasoline-powered cars on a diet of 100% renewable fuel.

The six-month pilot began in July 2026 and will involve around 20 Toyota and BMW vehicles operating exclusively on Repsol's Nexa 95 renewable gasoline. Bosch will monitor and verify how the fuel is used through its Digital Fuel Twin tracking system.

The objective is to prove that existing gasoline vehicles can reduce their overall lifecycle carbon footprint without major mechanical changes or entirely new refueling infrastructure. Supporters see renewable gasoline as a potential complement to electrification, particularly for the millions of combustion-powered vehicles already on European roads.

Toyota and BMW also hope the trial will help influence future European transport policy. With regulators debating how different low-carbon technologies should fit into long-term emissions targets, the companies want renewable fuels to be considered alongside battery-electric and hydrogen solutions.

One of the biggest selling points of the project is simplicity. The vehicles used in the trial are standard Toyota, Lexus, BMW, and Mini models drawn from existing fleets rather than purpose-built prototypes.

Repsol's Nexa 95 is designed to work as a drop-in replacement for conventional gasoline. That means the cars can use their existing engines and fuel systems while refueling through familiar service-station infrastructure.

The renewable gasoline is produced from feedstocks that comply with European sustainability requirements, including waste and residue-based materials. Sources associated with the project have cited examples such as used cooking oil and animal fats, although Repsol has not publicly detailed every component used in the fuel.

The project is not simply about filling a few cars with alternative gasoline and seeing whether they run. Bosch's Digital Fuel Twin system will track and verify fuel use across the supply chain, combining vehicle data, fuel-station records, and payment information.

The idea is to create a reliable digital record showing that participating vehicles are genuinely running on renewable fuel. That kind of traceability could become important if regulators eventually create special rules for vehicles that operate exclusively on approved low-carbon fuels.

Toyota and BMW refer to the concept as Vehicles Exclusively Running on Eligible Fuels, or VEEF. The companies argue that digital certification could help separate genuine renewable-fuel use from ordinary fossil gasoline consumption.

Spain was selected because Repsol already has renewable gasoline available through public filling stations there. The company says it is currently the only supplier offering 100% renewable gasoline at public service stations in the country.

That gives the pilot access to a real-world fueling network rather than a closed test facility. It also allows the companies to study whether renewable gasoline can work at scale using infrastructure that drivers already understand.

For Toyota and BMW, that practical compatibility is the central argument. Electrification requires buyers to purchase new vehicles and often depends on access to charging, while renewable gasoline could theoretically begin reducing the lifecycle emissions of existing combustion vehicles immediately.

The term "renewable gasoline" does not mean the fuel produces zero emissions when burned. Cars using it still release carbon dioxide from their exhausts, just as they do with conventional gasoline.

The environmental argument instead focuses on where the carbon originates. Renewable fuels are produced from recently existing biological or renewable sources rather than extracting additional fossil carbon that has been stored underground for millions of years.

Supporters therefore measure the benefit across the full fuel lifecycle rather than only at the tailpipe. Repsol says its renewable fuels can deliver substantial greenhouse-gas reductions compared with conventional fossil fuels, although the exact savings depend on feedstock, production, transportation, and other lifecycle factors.

Toyota has long argued that the transition away from fossil fuels should involve multiple technologies rather than relying exclusively on battery-electric vehicles. BMW has taken a similar position, continuing to invest in EVs while also supporting hydrogen and renewable fuels.

The two automakers believe fuels such as Nexa 95 could help reduce emissions from both new and existing combustion-powered cars. They also see potential for hybrids and plug-in hybrids to operate with lower lifecycle emissions when paired with renewable fuel.

Data from the Spanish pilot will eventually be shared with policymakers and industry groups as part of the broader debate over Europe's future emissions regulations. The companies are hoping to prove that decarbonizing road transport does not necessarily require every gasoline-powered car to disappear overnight.

Whether renewable gasoline can become affordable and plentiful enough to make a meaningful difference remains a much bigger question. Still, Toyota, BMW, Repsol, and Bosch are betting that one path toward cleaner transportation might involve keeping familiar engines on the road - while dramatically changing what goes into their fuel tanks.