Horse Powertrain, a fast-rising name in hybrid vehicle technology, has unveiled a bold new concept engine designed to run entirely on renewable fuel. Partnering with Spanish energy company Repsol, the firm introduced the H12 Concept, an evolution of its turbocharged 1.2-liter HR12 engine. This prototype represents a significant step toward cleaner mobility, promising both improved efficiency and reduced emissions.

Hybrid systems powered by renewable fuels may prove to be a vital complement to electric vehicles in the global transition to net-zero mobility.


Horse Powertrain emerged in 2023 as a spinoff from the Geely-Renault joint venture, initially raising eyebrows for its focus on combustion and hybrid engines at a time when the industry seemed fully committed to electrification. Yet within just three years, shifting consumer demand and regulatory adjustments have created space for hybrid solutions as a practical bridge toward net-zero goals. By 2025, Horse had become the world’s third-largest engine manufacturer, supplying brands such as Volvo, Nissan, Mitsubishi, Renault, and Geely, while operating 17 manufacturing plants and five R&D centers worldwide.

The collaboration highlights a “technology-neutral” approach—combining electric, hybrid, and renewable fuel solutions for faster sustainability gains.  



The H12 Concept engine showcases how renewable fuels can complement advanced hybrid systems. Running on Repsol’s Nexa 95 gasoline—produced entirely from renewable sources such as agricultural waste, forestry byproducts, and used cooking oils—the engine achieves a peak brake thermal efficiency of 44.2%. Technical refinements include a 17:1 compression ratio, optimized turbocharging, a new exhaust gas recirculation system, a high-energy ignition setup, and a reworked hybrid gearbox for better energy management. Together, these innovations deliver fuel consumption as low as 3.3 L/100 km (about 71 mpg), representing a 40% improvement over the European average for combustion vehicles in 2023.

A midsize car powered by this engine could cut up to 1.77 tons of CO2 emissions annually compared to fossil-fuel alternatives.  



The environmental impact is equally striking. Horse and Repsol estimate that a midsize vehicle equipped with the H12 Concept could cut up to 1.77 tons of CO2 emissions annually compared to a conventional internal combustion engine running on fossil fuels. Repsol’s renewable gasoline itself is compatible with existing vehicles without modification, offering a potential pathway to immediate emissions reductions while broader electrification strategies continue to evolve. The company has already scaled production of Nexa 95 at an industrial level and is expanding capacity with additional facilities.

Horse Powertrain has already built two prototype H12 engines, with a demonstrator vehicle expected to debut soon. 

Horse COO Patrice Haettel emphasized the importance of a “technology-neutral” approach, arguing that relying solely on one solution—such as electrification—may not be the fastest way to reduce emissions. Instead, combining innovations across electric, hybrid, and renewable fuel technologies could accelerate progress toward sustainability. Two prototype H12 engines have already been built, with a demonstrator vehicle expected to debut soon.

This development underscores a growing recognition that the road to net-zero transportation will not be defined by a single technology. Hybrid systems powered by renewable fuels may prove to be a vital complement to electric vehicles, offering automakers and consumers practical options in the transition to cleaner mobility.

Source: New Atlas