Horse and Repsol develop high-efficiency hybrid engine

Horse Powertrain and Repsol have developed a hybrid powertrain that achieves 44.2% peak brake thermal efficiency while running on 100% renewable gasoline. The HORSE H12 Concept engine reduces fuel consumption by 40% compared to 2023 European averages, achieving below 3.3 litres per 100 kilometres under WLTP testing.

The powertrain was developed by teams at Horse Technologies in Valladolid and the Repsol Technology Lab in Madrid. Technical features include a 17:1 compression ratio combustion system, a new exhaust gas recirculation system, an optimised turbocharger and an improved hybrid gearbox. A demonstrator vehicle is expected in early 2026.

Repsol began producing 100% renewable gasoline at industrial scale at its Tarragona facility in October 2025. The fuel is now available at 30 service stations in Spain under the Nexa 95 brand.

Patrice Haettel, Chief Operating Officer at Horse Powertrain and Chief Executive of Horse Technologies, said: “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.”

Luis Cabra, Executive Managing Director of Energy Transition at Repsol, added: “This collaboration shows that decarbonisation can be accelerated through innovative and accessible technological solutions.”

Source: Horse Powertrain