Renfe Tests HVO Fuel on Costa Verde Train in Asturias

ASTURIAS, Spain – Renfe and Repsol completed a real-world trial of 100% renewable HVO fuel powering a Costa Verde tourist train on non-electrified track in Asturias, reported on 12 August 2026, with Repsol supplying 1,000 litres of Nexa fuel to the El Berrón depot. The trial used a Class 619 locomotive after its conventional diesel tank was completely emptied. Renfe confirmed the locomotive operated correctly under normal passenger service conditions.

What Are the Technical Specifications?

The trial used Repsol’s Nexa 100% renewable HVO fuel in an unmodified Class 619 locomotive after its conventional diesel tank was completely emptied at the El Berrón maintenance depot. Renfe provided technical information about the locomotive and generator engines to Repsol and prepared the vehicle for operation exclusively on HVO. The fuel tank of the Class 619 locomotive was emptied of conventional diesel before the test began. Repsol delivered 1,000 litres of Nexa fuel free of charge to El Berrón. Renfe stated the tests confirmed correct operation under real operating conditions. The Tourist Trains Division supplied rolling stock, technical resources, and operational planning. The exact percentage reduction in CO₂ emissions for this trial was not disclosed.

Key Technical Data

Where Does This Technology Stand in the Market?

HVO renewable diesel competes with both conventional diesel and new zero-emission fleet replacements on non-electrified rail corridors. Renfe’s low-capital fuel substitution contrasts with the fleet replacement scale seen elsewhere in 2025: Amtrak awarded Siemens Mobility a US$3.4 billion contract for 73 sustainable trains (Source: Siemens Mobility, 2025), and Alstom was commissioned to supply 234 Metropolis metro cars and CBTC signalling for Mumbai Metro Line 4 (Source: Alstom, 2025). The North American high-speed rail market is projected to reach US$8.90 billion in 2026, driven by rail modernisation and infrastructure investment (Source: Future Market Insights, 2026). Meanwhile, Tri-Rail carried more than 4.5 million passengers in 2025, the highest annual ridership recorded by the system (Source: Tri-Rail, 2025). Comparable data for HVO-specific passenger rail trials was not publicly available at time of publication.

Competing products include Neste MY Renewable Diesel, an HVO100 drop-in fuel with established supply chains across Europe and up to 90% lifecycle greenhouse gas savings (Source: Neste, 2024), and Alstom’s Coradia iLint hydrogen multiple unit, which offers zero tailpipe emissions but requires new rolling stock and hydrogen refuelling infrastructure (Source: Alstom, 2022). Repsol Nexa’s advantage is compatibility with existing Class 619 locomotives, avoiding the capital cost of new trainsets but depending on renewable fuel supply and cost.

Editor’s Analysis

Renfe’s HVO trial shows that passenger operators can reduce emissions on unwired tourist and regional lines without waiting for infrastructure electrification or new rolling stock, a near-term complement to the 94% of Renfe Viajeros demand already met by zero-emission traction power in 2025. The Amtrak–Siemens order and the projected US$8.90 billion North American rail market indicate that fleet replacement remains the larger investment pathway, while fuel substitution may offer a faster, lower-cost bridge on legacy diesel routes (Source: Future Market Insights, 2026). The absence of a disclosed rollout timeline leaves open whether this trial becomes standard practice or remains a pilot.

FAQ

Q: What is HVO and why is Renfe testing it on tourist trains?
A: HVO (Hydrotreated Vegetable Oil) is a renewable diesel substitute made from vegetable oils and waste fats through hydrotreatment. Renfe tested Repsol’s Nexa HVO on the Costa Verde tourist train to reduce emissions on non-electrified lines without major modifications to existing rolling stock.

Q: Did Renfe need to modify the Class 619 locomotive to run on Nexa HVO?
A: No major modifications were required. Renfe emptied the conventional diesel tank and prepared the locomotive for operation exclusively on HVO, with Repsol supplying 1,000 litres to El Berrón depot.

Q: Will Renfe expand HVO use to other diesel services?
A: Renfe said the trial demonstrates technical viability and supports expanding the use of renewable fuels on non-electrified lines, but no fleet-wide rollout or specific timeline has been officially confirmed.