Renfe is taking a new step in its decarbonisation strategy, having successfully tested the use of HVO (Hydrotreated Vegetable Oil) renewable fuel on a tourist train operating on non-electrified lines.
The trial, carried out in collaboration with the energy company Repsol, demonstrates that this fuel can be a viable alternative to conventional diesel, without requiring major modifications to the existing rolling stock.
The first application in passenger services took place on the Costa Verde tourist train, where the 100% renewable Nexa fuel supplied by Repsol was used. Prior to the test, Renfe provided its partner with technical information regarding the locomotive and the generator engines, and prepared the vehicle for operation exclusively on HVO.
To this end, the fuel tank of the Class 619 locomotive was completely emptied of conventional diesel, and Repsol delivered 1,000 litres of renewable fuel free of charge to the El Berrón maintenance depot in the Asturias region.
The tests confirmed that the locomotive operated correctly under real operating conditions, providing further evidence in favour of expanding the use of renewable fuels on the non-electrified rail network.
HVO: a solution for reducing emissions on non-electrified lines
The initiative forms part of the collaboration agreement signed between Renfe and Repsol to promote the use of renewable fuels in rail services where infrastructure electrification is not yet available.
Renfe’s decarbonisation strategy is based primarily on the use of electricity from renewable sources on electrified lines, but the company is also developing solutions to reduce emissions from diesel trains. According to the Spanish operator, in 2025, 94 per cent of Renfe Viajeros’ transport demand was met through journeys with no greenhouse gas emissions from traction power, ensuring carbon-neutral transport.
Renfe states that this trial demonstrates the technical viability of renewable fuel in its operations and strengthens collaboration with strategic partners to move towards increasingly sustainable mobility.
The agreement between Renfe and Repsol forms part of the operator’s Sustainability Master Plan, approved in 2024, which aims to reduce its carbon footprint by identifying alternatives to fossil fuels for non-electrified lines.
The test involved several of Renfe’s technical teams, including the Tourist Trains Division, which provided the rolling stock, technical resources and operational planning required to evaluate the fuel under real-world conditions.
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