New analysis by SRK indicates that a 150-t payload battery-electric haul truck could end up being $3 million cheaper on a total cost of ownership (TCO) basis than the equivalent diesel model.

The report, titled, ‘Decarbonizing Mining: Diesel vs Electric Haul Trucks on Cost and Efficiency: Assessing Economic and Operational Trade-offs’, compares the TCO and operational efficiency of 150 t diesel and electric haul trucks.

The authors, Satadru Ghosh – Mechanical Engineer (Research Intern), Somnath Gain, Principal Consultant – Mining, Sudipta De, Principal Consultant – Mining, stated: “Electric trucks, particularly those powered by lithium iron phosphate (LFP) batteries, offer substantial benefits. These batteries are cost-effective; compared to other battery types they have a longer cycle life and lower environmental impact, providing significant energy and maintenance cost savings, despite higher initial capital expenditure.

“Operationally, electric haul trucks can reduce the cost per tonne of material moved by 65%, enhance operational efficiency through better torque and regenerative braking systems (which recover energy during braking and store it for reuse), and demonstrate superior performance metrics, including increased tonnes hauled and speed. Environmentally, electric trucks contribute to cleaner and quieter mining operations with significant reductions in energy costs and CO2 emissions.”

Challenges such as battery technology, charging infrastructure and productivity remain; however, advances in battery technology, rapid charging systems and battery swapping are promising solutions to these issues, the authors added.

“As these technologies evolve, electric haul trucks are expected to become increasingly viable, offering substantial financial and environmental benefits and transforming mining operations toward greater sustainability.”

This analysis evaluates the TCO for 150 t haul trucks, comparing diesel models with those powered by LFP batteries. The decision to focus on LFP batteries was driven by several key factors that align well with the demands of heavy-duty mining equipment.

Desktop research conducted by the authors found the LFP battery, with a capacity of 2,200 kWh, supports operations for approximately 8 hours on a full charge. LFP batteries are also considered cost-effective and offer an extended cycle life. In addition, thermal stability is another significant LFP battery strength, while LFP batteries have a lower environmental and supply chain impact compared with other chemistries like nickel-cobalt-aluminium (NCA) or nickel-manganese-cobalt (NMC).

“While LFP batteries do have a lower energy density compared to other battery types, storing less energy per unit of weight, this limitation is less critical for haul trucks,” the authors said. “These vehicles are already designed to carry heavy loads, so the slightly reduced energy density of LFP batteries does not pose a significant disadvantage. Instead, the trade-off is justified by the battery’s cost-effectiveness, safety and environmental benefits, making LFP an optimal choice for powering 150 t haul trucks in mining operations.”

Both truck types are assessed under identical operational conditions. Although electric haul trucks come with a higher initial capital expenditure, they present significant financial advantages over a 10-year horizon, according to the authors, with their analysis showing potential savings of around $3 million, even after accounting for multiple battery replacements.

These savings primarily stem from reduced energy and maintenance costs, with, in its simplest explanaton, electricity being cheaper than diesel fuel. Furthermore, electric trucks require less maintenance due to their simpler mechanical design and lack of complex exhaust systems.

“One notable advantage of electric haul trucks is the absence of idling fuel consumption,” the authors said. “While diesel trucks use fuel continuously, electric trucks do not draw energy when stationary, making 1 diesel truck hour roughly equivalent to 0.8 battery truck hours.”

Additionally, regenerative braking technology allows electric haul trucks to recover and store energy during downhill operations, further enhancing efficiency.

With rapid advancements in battery technology, charging times have improved significantly, with a full recharge from 0 to 100% now achievable within 1 to 1.5 hours, according to projections from Fortescue Zero.

The authors added: “While the upfront investment in electric haul trucks is higher, the substantial long-term financial benefits, including major reductions in energy and maintenance costs, as well as efficiencies from regenerative braking and faster charging times, make them a compelling alternative to diesel trucks under identical operational conditions.

“Crucially, the capital expenditure for electric haul trucks is recovered by the third year of operation, underscoring the swift return on investment through reduced operational and maintenance costs.”

Operational efficiency: diesel versus electric trucks

• Cost efficiency: The 150 t diesel haul truck with a cycle time of 1 hour, consumes 100 litres of diesel per hour. With diesel priced at $1 per litre, the energy cost to move 150 t of material amounts to $100 per hour. In contrast, the electric truck consumes approximately 275 kWh of energy per hour, translating to an energy cost of around $35/hr, resulting in a 65% reduction in the cost to move 150 t of material;
• Operational efficiency: Electric trucks offer significant improvements in operational efficiency due to higher torque at lower speeds and regenerative braking systems. For example:
  • Boliden reported a 15% reduction in cycle time with electric trucks;
  • New Afton gold mine experienced a 56% decrease in mucking cycle time compared with diesel equipment, using the Sandvik LH518B and Sandvik Z50 truck;
• Performance: Pretivm’s Brucejack gold mine in British Columbia, Canada, using the Sandvik Z50 truck, reported:
  • More than 90% machine availability;
  • Speeds of 9.5 km/h on a 15% grade with a 42 t load;
  • Battery swap times of less than 10 minutes;
  • 42% increase in tonnes hauled compared to a diesel-equivalent machine and a 22% boost in speed;
• Environmental Impact: The Huolinhe coal mine in Inner Mongolia using an all-electric truck converted by Xiangtan Electric Manufacturing Co Ltd reported:
  • Energy savings: Daily power consumption costs of $263-298, compared with $1,480-1,970 for a diesel truck.
  • Reduced emissions: Benefitting from zero emissions, it is estimated annual CO2 emissions reduced by 1,500 t, contributing to a cleaner and quieter mining operation.

Battery technology remains a key obstacle to increasing uptake of electric haul trucks – with a unified standard in battery designs and chemistries complicating the selection of the optimal solution for mining applications. The authors also label charging infrastructure as another challenge, as electric trucks require high charging rates of 1 to 3C (where C refers to the charging rate relative to the battery’s capacity) to maintain productivity which can impact battery life and necessitate frequent replacements. Productivity concerns also contribute to the slow adoption of electric haul trucks, with the current iteration of electric trucks unable to match the uptime of diesel trucks, according to the authors. “Despite this, electric trucks offer advantages such as higher torque and regenerative braking systems, which can lead to reduced cycle times and increased material handling capacity over time,” they added.

The authors concluded: “Overall, the commitment of OEMs and the mining industry’s eagerness to adopt electric haul trucks underscore their potential. With significant financial and environmental benefits on the horizon, ongoing advancements in battery technology, charging infrastructure, and operational efficiency are expected to address the current limitations. As these solutions continue to develop, electric haul trucks are poised to become a more viable and transformative option for the mining sector.”