Rolls-Royce develops and tests hybrid powertrain for haul trucks to support efficient and sustainable mining

• Mine operators save up to 30% on fuel costs and CO2 emissions thanks to hybrid propulsion
• Rolls-Royce is set to test a pilot vehicle fitted with an mtu hybrid system at a mine later in 2026
• Modular, integrated solution for retrofitting existing haul trucks

Rolls-Royce Power Systems is developing a hybrid drive system for haul trucks and will begin field testing it from autumn 2026 at a mining location. The system combines proven mtu Series 4000 engines with a high-performance electric drivetrain. Depending on the topography and operational profile of the mine, this can result in savings of up to 30 per cent in fuel consumption and CO₂ emissions compared to conventional drive systems. Rolls-Royce will present the development concept at the Electric Mine Conference on 7 May 2026 in Lisbon, Portugal.

The hybrid system stores the haul truck’s braking energy in batteries during downhill journeys. This energy is then used to drive the wheel motors during the subsequent uphill journey. As a result, the diesel engine operates under a lower load – and consumes significantly less fuel. At the same time, CO₂ emissions are reduced. The aim is a modular, scalable system that can be adapted to different vehicle types, mine topographies and operating conditions.

“With this new development, Rolls-Royce is responding to a growing drive from the global mining industry to operate more efficiently and sustainably,” explained Cobus van Schalkwyk, Vice President Global Mining at Rolls-Royce Power Systems. 

Demand for critical minerals for the energy transition, electromobility and large data centres is rising rapidly. At the same time, leading mining companies have committed to reducing their CO₂ emissions by 30 to 40 per cent by 2030 and to operating in a climate-neutral manner by 2050. 

“Transport in open-pit mining using haul trucks accounts for the largest share of production costs – and a significant proportion of emissions. Hybrid drive systems offer an effective lever for cost reduction and decarbonisation here,” said van Schalkwyk.

For decades, mtu diesel engines have been reliably powering vehicles for open-pit mining: from blast hole drilling rigs to excavators and wheel loaders, right through to haul trucks and other mining machinery, whether diesel-mechanical, diesel-electric or diesel-hydraulic.

The engines of the mtu Series 4000 were developed for powerful, versatile and, at the same time, efficient continuous operation. Furthermore, the key variants are approved for use with the sustainable fuel HVO (hydrogenated vegetable oil) which already enables a significant reduction in their carbon footprint.