Horse Powertrain and Repsol jointly develop a new hybrid powertrain running on 100% renewable gasoline

Horse Powertrain, via its Horse Technologies division, and Repsol have unveiled a next-generation hybrid powertrain that achieves ultra-high efficiency and low fuel consumption, operating on 100% renewable gasoline.

The HORSE H12 Concept engine introduces enhancements to the combustion system and reductions in internal losses, achieving 44.2% peak brake thermal efficiency (BTE) while reducing vehicle fuel consumption by 40% (in comparison with 2023 average passenger car new registration in Europe) to below 3.3 liters per 100 kilometers, according to standardized European testing (WLTP).

Maximizing efficiency directly results in lower fuel consumption and lower CO2 emissions in equal proportions. When using the 100% renewable fuel, a mid-sized car equipped with the HORSE H12 Concept powertrain and driving an average of 12,500 kilometers per year, will emit 1.77 tons of CO₂ per year less than a vehicle with a traditional fuel and combustion engine.

The hybrid powertrain system incorporates the HORSE H12 Concept engine, an evolution of the HR12 engine that includes an innovative combustion system designed at a 17:1 compression ratio, a new-generation exhaust gas recirculation system (EGR), an optimized turbocharger, a high-energy ignition system, and an improved hybrid gearbox with optimized energy management, as well as reduced internal friction enabled by new Repsol lubricants.

The project, led by teams from the Horse Technologies Division in Valladolid and the Repsol Technology Lab in Madrid, has produced its first two prototypes and validated performance. The first demonstrator vehicle is expected to be presented in early 2026. This is the first step towards industrial production of highly-efficient hybrid engines.

Luis Cabra, Executive Managing Director of Energy Transition, Technology, Institutional Affairs and Deputy CEO of Repsol, states: “This collaboration shows that decarbonization can be accelerated through innovative and accessible technological solutions. The use of 100% renewable fuels is a net zero emission solution, complementary to electric vehicles, for decarbonizing the transport sector. Supporting clear and ambitious regulation that drives investment in renewable fuels and highly efficient engines is essential for Europe to reduce transport emissions faster in a more competitive and effective manner.”

Patrice Haettel, Chief Operating Officer at Horse Powertrain and Chief Executive Officer at Horse Technologies, adds: “The HORSE H12 Concept is an example of how highly efficient engines and renewable fuels can reduce emissions today, without waiting for future solutions. As a company, we believe that relying on a single technology is not the fastest way to cut emissions. This is why we advocate a technology neutral approach that enables innovation across all solutions – electric, hybrid, range extenders and low-carbon fuels.”