Why Diesel Still Dominates Mining Emissions Reduction Plans

Most investors assume mining is going electric. The numbers say otherwise: diesel combustion accounts for 91% of BHP‘s operational CO₂ emissions, and diesel’s share of the company’s Scope 1 (direct) emissions climbed from 63% in FY2021 to 80% in FY2025, according to an April 2026 analysis by the Institute for Energy Economics and Financial Analysis (IEEFA). For anyone following mining emissions reduction, that is the opposite of the expected direction.

Miners face mounting pressure to cut emissions, yet their heavy haul fleets are widely expected to stay diesel-powered until around 2040. That leaves a long stretch where “bridge” measures, such as cleaner fuels, smarter fleets and autonomy, carry the decarbonisation story.

For you as a mining and energy investor, the question is which of those levers actually reduce emissions and which mostly reduce scrutiny.

Here is how to sort the proven from the promoted, so you can judge which bridge strategies deserve your confidence. One caveat runs throughout: much of the public material on these levers is sponsored content linked to ExxonMobil, a fuel and lubricant supplier, so vendor claims are flagged as such.

Why does diesel still dominate the mine site?

A mine runs on two energy systems. Grid electricity powers fixed plant such as crushers, mills and ventilation, and supplies roughly half of a typical mine’s energy. Diesel fuels everything that moves: haul trucks, loaders and auxiliary machinery.

The grid half is the easier half. You can swap a power contract for renewables without touching a single truck. The diesel half is where the emissions problem lives, and the miner-level data shows how stubborn it is.

Putting the diesel problem in context means looking at mining’s share of global emissions, because your view of how much fleet decarbonisation matters depends on how large the sector’s total footprint is across extraction and processing.

These are company-level figures because no global diesel-share dataset from the International Energy Agency (IEA) or the International Council on Mining and Metals (ICMM) is publicly available. The scale per machine helps explain them: one ultra-class haul truck can burn nearly one million litres of diesel a year while running up to 18 hours a day.

Four drivers keep diesel in place:

1. Extremely high energy demand per tonne moved.
2. The difficulty of building charging or trolley infrastructure at remote sites.
3. Long asset lives and sunk capital in existing diesel fleets.
4. Reluctance to risk high-utilisation haul cycles on unproven technology.

Battery-electric vehicles are barely used today, with early adoption underground and major engineering hurdles for large surface trucks. ExxonMobil-sponsored content citing Frost & Sullivan research says diesel equipment will predominate until 2040, and that about 75% of operators treat emission cuts as a core part of strategy.

If you hold or are weighing mining equities, this tells you diesel exposure is the main lever on a miner’s Scope 1 profile. A company’s fleet plan matters more than its grid-power pledges.

How do efficiency, fleet data and autonomy trim diesel use?

If the diesel can’t be removed quickly, the next move is to burn less of it. The available levers form a ladder, from cheap tweaks to large equipment programmes.

Efficiency and data levers

The bottom rungs require little capital:

• Performance diesel with detergents that keep engines clean and preserve combustion efficiency
• Synthetic lubricants in engines, transmissions and drivetrains
• Telemetry and fleet analytics that pinpoint idle hotspots, queuing and poor routing
• Autonomous operation, which keeps throttle steady and braking smooth
• Newer engines and diesel-electric drives, which deliver some electrification benefits without charging infrastructure

The savings claims for the first three come from ExxonMobil-sponsored material. Mine-level measured percentage savings are not publicly available, so you are being asked to accept the logic rather than the results.

Autonomy and equipment upgrades

Autonomy is growing fast, though counting it is messy. A 2026 technical review put the global autonomous haul truck fleet at 3,832 units in mid-2025. GlobalData reported 5,684 units as of July 2026, with China alone at 3,843.

Dataintelo‘s figure of about 1,200 units reflects a narrower scope, which is why the counts disagree. Vendor content says autonomy rose from 1% to 4% of fleets between 2021 and mid-2025, but the technical review states no reliable share-of-fleet estimate exists.

Milestones keep arriving. Komatsu commissioned its 1,000th ultra-class autonomous truck in 2026 at Barrick‘s Nevada Gold Mines, while Caterpillar reported about 690 trucks on its Command system at the end of 2024.

The case for autonomous haulage safety and efficiency is well documented, which is why fleet growth is better read as a productivity story than as evidence of proven emissions savings.

Yet IEEFA’s April analysis carries a blunt headline:

IEEFA report title “Fuel efficiency alone won’t dig coalminers out of a deepening diesel hole”

For you as an investor, rapid autonomous fleet growth signals productivity spending more than proven emissions savings. Ask any miner for measured fuel-intensity results, not truck counts.

What is renewable diesel (HVO), and how well is it proven?

The next rung swaps the fuel itself. This is where the bridging case sounds most persuasive, and where the evidence thins out most.

How HVO works as a drop-in fuel

Hydrotreated vegetable oil (HVO) is a renewable diesel made from fats and oils that can replace fossil diesel with little or no engine modification. “Drop-in” means it goes into the existing tank and engine. Several equipment makers support its use.

That is its appeal for you to understand: a miner can lower lifecycle emissions without buying new trucks or building infrastructure. Lifecycle emissions count everything from producing the fuel to burning it.

What the pilots do and do not show

The flagship case is Imperial Oil‘s Kearl oil sands site in Canada, where Caterpillar ultra-class trucks ran on 100% renewable diesel with similar power and performance in harsh conditions. Rio Tinto‘s Kennecott copper operation in the US is also cited as a successful user.

Neither site has published quantified fuel-use or CO₂ results. Imperial Oil is an ExxonMobil affiliate, so Kearl is a related-party case promoted in its partner’s sponsored content.

Details of Rio Tinto’s renewable diesel trial offer a further data point on how a major miner is testing drop-in fuels, though lifecycle results remain the missing piece.

Supply is the harder limit. Waste oils and lipids are finite, feedstocks compete with food and land use, and lifecycle accounting needs site-specific baselines. Even the July 2026 sponsored feature conceded the task now is spreading early experience across a wider share of the industry.

This tells you HVO is best treated as a tactical, pilot-stage lever with unresolved cost and supply. Any miner claiming large near-term cuts from it should show lifecycle data.

Are bridge strategies enough, or does electrification have to speed up?

With the ladder laid out, two camps read it very differently.

ExxonMobil-linked analyses describe a step-wise path: improve diesel efficiency first, then layer in HVO pilots alongside digital optimisation. They pitch this as a “triple dividend” of productivity, efficiency and lower emissions per tonne, while deferring the capital and technical risk of full electrification.

IEEFA’s reply is the BHP data. Diesel’s Scope 1 share rose from 63% to 80% despite efficiency efforts, which suggests incremental measures are not shrinking dependence and that deeper change, such as electrification or operational redesign, is required.

Battery-electric trucks sit in the middle as a medium-term shift. Market Intelo estimates electric autonomous trucks made up 12.4% of the autonomous haul truck market in 2025 (about US$0.5 billion), forecasting 24.3% annual growth over 2026-2034 and potentially a 25-30% share by 2034. It also claims 30-40% lower operating costs. EACON reports more than 1,500 battery-electric autonomous mining trucks deployed. These are market research projections, and mine-level trial data remains unpublished.

Questions worth putting to management:

• What measured change in fuel intensity has your fleet delivered?
• Have HVO pilots produced published lifecycle emissions data?
• What does HVO cost you versus fossil diesel, and is supply secured?
• When do battery-electric trials move beyond pilots, and at which sites?

You should read bridge strategies as risk-deferral tools rather than endpoints. Favour miners that disclose measured intensity trends and a credible electrification timeline.

For readers weighing battery-electric timelines, our deep-dive into electric mining truck charging infrastructure explains why charging, not the truck, is the real bottleneck.

Judging near-term mining emissions reduction claims with clear eyes

Diesel will remain central to heavy surface mining for years. The bridge levers are credible in principle but mostly unquantified in public, and IEEFA’s work shows they have not yet reduced diesel dependence at major miners.

Three signals will tell you whether that changes:

1. Published fuel-intensity or lifecycle data from HVO and efficiency pilots.
2. Evidence that HVO cost and feedstock supply can scale.
3. Battery-electric trial results from major miners.

Keep the provenance in mind as you weigh each update: much of the optimistic material comes from a fuel supplier with a commercial stake in the outcome.

Projections cited are subject to market conditions and various risk factors, and past performance does not guarantee future results. These statements are speculative and subject to change based on market developments and company performance.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.