For much of the past decade, the future of road transport has increasingly been framed around one dominant transition: replacing internal combustion engines with electric vehicles.
But there is another question worth asking. What happens to the millions of gasoline-powered vehicles that will remain on the road as that transition unfolds?
A new real-world trial in Spain could provide part of the answer.
In July, Repsol, Toyota Motor Europe, BMW Group, and Bosch launched a six-month pilot to demonstrate how existing vehicles can operate exclusively on 100% renewable gasoline under everyday driving conditions. The project will deploy a fleet of around twenty Toyota and BMW vehicles fueled with Repsol's Nexa 95 renewable gasoline. Bosch will provide digital technology to track and verify the renewable fuel used by the vehicles.
On the surface, the trial is straightforward. Put renewable gasoline into conventional vehicles and see how they perform.
But its implications go much further.
The pilot tests whether renewable gasoline can work across much of the existing transportation system:
Cars Using the Fuel
Filling Stations
Fuel Distribution Networks
Supporting Infrastructure Built Around Liquid Fuels
The pilot also tests whether the renewable origin and consumption of that fuel can be reliably tracked and certified. If those pieces work together, renewable gasoline could offer another route to reducing road-transport emissions without waiting for every existing combustion-engine vehicle to be replaced.
That is what makes this trial significant. It is also where the harder questions begin.
Repsol's Nexa 95 is produced from feedstocks compliant with the EU Renewable Energy Directive and is designed to be fully compatible with existing gasoline engines and infrastructure. According to Repsol, it can provide significant greenhouse gas emissions reductions compared with conventional fossil gasoline.
The pilot has three primary objectives.
First, the partners want to demonstrate the availability of renewable gasoline in an actual retail fuel market. Repsol says it is currently the only supplier offering 100% renewable gasoline at public filling stations in Spain.
Second, Bosch's Digital Fuel Twin technology will collect and validate refueling information using vehicle data, filling-station data, and fuel-card transactions. The goal is to create a transparent record showing that renewable fuel entered the market and was ultimately consumed by a particular vehicle.
Third, Toyota and BMW vehicles will demonstrate that existing cars can operate on the fuel in normal conditions without requiring an entirely new vehicle or refueling ecosystem.
Taken together, those objectives make the project much more than an engine test. The partners are effectively testing a miniature renewable gasoline value chain:
Production and Supply → Retail Availability → Vehicle Compatibility → Fuel Consumption → Digital Certification
That distinction matters because the question of whether renewable gasoline works is no longer the only relevant one. The bigger question is whether it can work at scale.
Electrification remains central to the long-term decarbonization of passenger transport. But even rapid growth in electric vehicle sales does not immediately eliminate emissions from the existing vehicle fleet.
Cars can remain on the road for many years. Every gasoline vehicle sold today potentially represents years of future liquid-fuel demand. And the pace of fleet turnover differs considerably across countries and markets.
This creates a gap between changing the technology of new vehicles and reducing emissions from the vehicles already in use.
Renewable gasoline offers a potentially critical advantage in addressing that gap: compatibility.
Rather than requiring consumers to purchase a different vehicle or governments and businesses to first construct an entirely new refueling network, a drop-in renewable fuel could use existing engines, filling stations, storage tanks, and distribution infrastructure.
That does not make renewable gasoline a replacement for electrification. And it also does not mean that every gasoline vehicle could or should ultimately be supplied with renewable fuel.
It means the two pathways address somewhat different parts of the decarbonization problem.
Electrification can progressively change the composition of the vehicle fleet.
Renewable fuels could potentially reduce the carbon intensity of at least some of the liquid fuel consumed by the fleet during that transition.
Indeed, the European policy environment itself is evolving. The European Commission's December 2025 automotive package proposed maintaining a strong electrification signal while introducing additional technological flexibility.
Under the proposed framework, manufacturers would face a 90% reduction in tailpipe emissions from 2035. The remaining emissions would be addressed through measures such as e-fuels and biofuels.
The Repsol pilot therefore arrives as Europe is actively considering what a more technology-neutral approach to vehicle decarbonization could look like.
The appeal of renewable gasoline is fairly easy to understand. If a lower-carbon fuel can be introduced into an enormous installed base of vehicles and infrastructure, the challenges associated with replacing physical assets become considerably smaller.
But infrastructure compatibility should not be confused with market scalability.
A renewable gasoline market ultimately has to answer several difficult questions:
Where will the feedstocks come from?
How much renewable gasoline can realistically be produced?
What will it cost relative to conventional gasoline and competing low-carbon alternatives?
Where will producers earn the strongest returns for limited renewable feedstocks?
How will regulators determine and verify the emissions reductions associated with the fuel?
These are ultimately questions of markets, not engines. And they may prove far more difficult than demonstrating that a Toyota or BMW can run on renewable gasoline.
Any attempt to significantly expand renewable gasoline production immediately runs into the issue that confronts much of the renewable fuels industry: feedstock availability.
Renewable fuel production depends on access to eligible renewable and waste-derived raw materials. Those resources are not unlimited, and renewable gasoline is far from the only market competing for them.
Renewable diesel, sustainable aviation fuel, marine fuels, and other low-carbon products are all drawing investment and policy support. Depending on production pathways and refinery configurations, producers must therefore consider two components:
Whether they can produce renewable gasoline
Whether gasoline represents the most attractive use of available feedstock and processing capacity
That competition becomes increasingly important as renewable fuel mandates expand.
A successful demonstration involving twenty vehicles will prove something useful about deployment. Scaling that proof of concept across thousands, and potentially millions, of vehicles presents a far greater supply challenge.
This is where the renewable gasoline story becomes an allocation story.
Limited feedstocks, production capacity, policy incentives, and demand from multiple transportation sectors will influence where renewable fuels ultimately go. If another market offers stronger regulatory incentives or higher margins, production may naturally flow there instead.
The future of renewable gasoline depends not only on technical demand from gasoline vehicles, but also on its ability to compete for supply within a much larger low-carbon fuels market.
There is also the unavoidable question of price.
Drop-in compatibility reduces one type of cost because consumers and fuel suppliers may not need to replace vehicles or build entirely new infrastructure. But the fuel itself still needs to compete economically.
Renewable feedstocks can command substantial premiums over fossil-based raw materials. Processing, certification, logistics, and compliance requirements add additional costs.
That means the commercial case for renewable gasoline will depend heavily on policy.
Several incentives can also influence the relative economics of renewable and fossil fuels:
Carbon Prices
Renewable Fuel Mandates
Tax Treatment
Emissions Standards
Credits
Without sufficient regulatory value for carbon reduction, the fact that renewable gasoline can be used in an existing car may not be enough to create widespread demand.
The market needs something more complicated than a compatible fuel. It needs an economic mechanism that assigns value to the emissions reduction associated with that molecule.
That helps explain why Bosch's role in the Spanish pilot deserves particular attention.
The Digital Fuel Twin is designed to track renewable fuel through the value chain and verify its use in individual vehicles. At first glance, digital fuel tracking may seem secondary to the more eye-catching prospect of cars running on 100% renewable gasoline. In reality, it could be one of the most important parts of the project.
Low-carbon fuel markets depend on the ability to demonstrate that a product qualifies under applicable regulations and delivers a specific emissions benefit. As renewable fuels move through conventional storage, distribution, and retail infrastructure, credible chain-of-custody systems become essential.
Without reliable certification, an emissions reduction is difficult to translate into regulatory or commercial value. The challenge, then, is not merely moving renewable fuels. It is moving information alongside those fuels:
Where the fuel came from
What the fuel was produced from
How the fuel moved through the supply chain
Where the fuel was consumed
What emissions reduction can legitimately be attributed to the fuel
That means the infrastructure supporting renewable gasoline may ultimately consist of two overlapping systems: the physical infrastructure that transports the fuel and the digital infrastructure that verifies its environmental attributes.
The Repsol, Toyota, BMW, and Bosch pilot will not answer every question surrounding renewable gasoline, nor should it.
Twenty vehicles operating for six months cannot demonstrate the economics of supplying an entire national vehicle fleet. It cannot create additional feedstock supply or determine how renewable molecules should be allocated among road transport, aviation, shipping, and other competing markets.
What it can do is test an important premise:
Can renewable gasoline move beyond controlled demonstrations and operate within today's transportation system?
If the answer is yes, the conversation changes.
The question is no longer whether renewable gasoline is technically possible. It is where it makes economic and environmental sense to deploy it, and how large that opportunity can realistically become.
That is a much more difficult and consequential consideration.
The transition away from fossil fuels will not happen simply by replacing one technology with another overnight. Vehicle fleets turn over gradually. Infrastructure takes time to build. Feedstocks are constrained. Regulations evolve. Consumers respond to price, convenience, and availability.
Renewable gasoline's most compelling proposition may be less about competing with electric vehicles and more about addressing a problem electrification cannot solve immediately. We must reduce emissions from combustion-engine vehicles that are already on the road.
The Spanish pilot suggests that the fuel, vehicles, filling stations, and digital tools can potentially work together. Now comes the hard part: determining whether the feedstocks, economics, policy frameworks, and supply chains can do the same.
Renewable gasoline is only one part of a much larger and increasingly interconnected biofuels market. Competition for feedstocks, changing regulations, international trade flows, and growing demand from road transport, aviation, and marine markets will influence where renewable fuels are produced, how they are priced, and where they ultimately find markets.
ResourceWise will explore these dynamics in our upcoming Biofuels Market Outlook: Q4 2026 webinar.
The webinar will examine where biofuel markets are heading following Q3:
Where feedstocks are tightening or becoming oversupplied
Developments around 45Z and US policy
RED III and European market dynamics
Chinese HVO exports
Emerging advanced feedstocks
The latest developments in sustainable aviation and marine biofuels