Introduction
Dual-Fuel Trucks from HWR.
A practical bridge to lower-emission heavy transport.
New Zealand’s heavy transport fleet cannot be replaced overnight. Trucks are expensive, remain in service for many years and must continue moving freight while new fuels and refuelling networks are developed.
HW Richardson Group’s hydrogen–diesel dual-fuel programme has been designed around that reality: reduce diesel use by retrofitting existing trucks, without waiting for an entirely new zero-emission fleet.
The programme has now demonstrated the technology across several demanding transport applications. Its principal achievement is not the complete elimination of emissions. The converted vehicles still use diesel. Its value is as a transitional business solution that can lower fuel-related carbon emissions while retaining existing engines, routes, payloads and operating practices.
How the Conversion Works
How the Conversion Works
The conversion supplements diesel combustion with hydrogen while retaining the truck’s original engine, drivetrain and full diesel fallback.
HWR developed its conversion capability through Change Fuel Technologies, working with overseas specialists and New Zealand manufacturers.
The system adds compressed-hydrogen storage, pipework, injectors, controls and safety equipment to a conventional diesel truck rather than replacing its engine and drivetrain.
Hydrogen is injected into the engine’s air intake and mixed with air during the intake and compression strokes. A smaller quantity of diesel remains the pilot fuel: it auto-ignites under compression and ignites the hydrogen–air mixture. The control system varies the two fuels while maintaining the energy demanded by the engine.
According to HWR’s technical description, a typical installation uses five tanks mounted behind the cab, each with a nominal capacity of 5 kg of hydrogen, giving a nominal total of 25 kg. EECA describes the five-tank trial configuration as holding about 23 kg. The published sources do not explain the difference, which may reflect nominal versus usable capacity or a configuration change. The certified usable capacity should therefore be confirmed for each proposed conversion. The system is designed to make use of available tare-weight allowance and minimise any reduction in payload. Electronic and mechanical sensors and shut-offs provide several layers of protection.
Crucially, the vehicle retains its ability to run entirely on diesel. If hydrogen is unavailable, the driver can continue the route rather than leaving the truck stranded. This feature addresses one of the largest commercial risks facing an emerging fuel: vehicles and infrastructure do not have to reach full national coverage at exactly the same time.
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Applications Completed
Applications Completed
HWR has tested the system across milk collection, general freight, bulk haulage and concrete delivery.
HWR began developing the concept in 2021 and put its first vehicle, known as Blue Hydro, into operation in 2023. It was described as the first hydrogen–diesel dual-fuel truck deployed in the Southern Hemisphere.
HWR now reports that multiple truck and trailer units are operating throughout New Zealand.
The programme deliberately moved beyond one vehicle type. EECA’s account of the trials identifies the following converted applications:
- DAF milk tanker;
- Volvo milk tanker;
- Volvo general-freight truck;
- DAF bulk-haulage trucks; and
- Mack concrete truck.
These projects test different operating conditions:
- Milk collection involves changing loads, rural roads and a demanding collection schedule.
- General freight provides sustained road operation.
- Bulk-haulage and bottom-dumper combinations operate at high mass and on civil-construction or aggregate work.
- A concrete mixer adds an urban, stop–start duty and auxiliary demand while carrying a time-sensitive product.
The first milk collection conversion was a New Zealand first, while HWR describes the concrete mixer as a world-first dual-fuel application of its type.
HWR’s 2024 Sustainability Report recorded eight dual-fuel vehicles on the road. Six larger vehicles were rated as capable of avoiding 205kg of carbon-dioxide-equivalent emissions per operating day, while two concrete mixers were rated at 39kg per day.
Six conversions received co-funding through EECA’s Low Emission Transport Fund, and HWR subsequently committed its own funding to a further four trucks for its internal businesses. This progression—from supported demonstration to company-funded deployment and a commercial conversion offering—is an important business outcome in itself. It indicates that the work has generated enough technical confidence to move beyond a single proof of concept.
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Diesel and Emissions Reductions
Diesel and Emissions Reductions
Trials report approximately 30% diesel displacement in dual-fuel operation, with the result varying by vehicle configuration, route, load and operating conditions.
The most consistently reported trial result is approximately 30% diesel displacement when the trucks operate in dual-fuel mode. Because hydrogen contains no carbon, replacing that portion of diesel also reduces tailpipe carbon dioxide by approximately 30%. HWR states that optimised installations can reduce carbon emissions by up to 40%, while its 2024 reporting used a figure of up to 34%. The difference reflects vehicle configuration, route, load and operating conditions; “up to” should not be treated as a guaranteed result for every truck or every journey.
EECA gives an example of a truck travelling about 380 kilometres per day. At the reported displacement rate, it could avoid approximately 200kg of carbon dioxide each operating day, or around 70 tonnes per year, without sacrificing its normal work. HWR’s later reporting used a closely aligned figure of 205kg per day for six of its vehicles.
These are substantial reductions for an interim technology, particularly when applied to high-mileage trucks. They are not zero-emission results. Diesel is still burned, producing carbon dioxide and other exhaust emissions. The complete climate outcome also depends on how the hydrogen is made, compressed and delivered. The strongest result occurs when the hydrogen is produced using renewable electricity and its lifecycle emissions are properly accounted for.
The Economic and Business Benefits
The Economic and Business Benefits
The conversion preserves existing fleet assets and operating practices while reducing diesel exposure and transition risk.
Preserving the Value of Existing Trucks
The largest immediate business benefit is avoided asset replacement. A fleet operator can reduce emissions without discarding a relatively new diesel truck or purchasing a completely new fuel cell or battery-electric heavy vehicle. The engine, chassis and much of the existing maintenance capability remain in use.
That protects capital already invested in the fleet and reduces the risk of creating stranded diesel assets. It also allows conversion to occur during the truck’s normal ownership life rather than requiring a fleet-wide replacement programme.
Maintaining Productivity
HWR and EECA report performance comparable with the original diesel trucks, including testing on hilly sections of State Highway 1. The system has been designed so that routes, distance, power and payload are not materially compromised. This matters commercially: a lower-emission truck produces little benefit if it requires another vehicle, an extra driver or fewer tonnes per trip to complete the same work.
The hydrogen storage is matched to daily vehicle use so hydrogen and diesel can be replenished together. EECA reports a hydrogen filling time of about seven minutes. Fast refuelling and diesel fallback reduce disruption to schedules and allow the converted trucks to operate within familiar fleet practices.
Reducing Exposure to Diesel
Displacing around 30% of diesel reduces the volume a fleet must buy from an entirely imported fuel supply. The financial saving depends on the delivered prices of hydrogen and diesel, so lower diesel consumption does not automatically mean a lower total fuel bill today. It does, however, diversify fuel exposure and creates the potential for a larger share of transport energy spending to support New Zealand electricity, engineering and fuel production.
HWR has coupled its vehicle programme with plans for local green-hydrogen production and dual-fuel retailing through Allied Petroleum. The company has also arranged a long-term renewable-electricity supply relationship intended to give its hydrogen programme more predictable energy pricing. This vertical approach connects demand from trucks with production and distribution, helping address the industry’s “vehicles before stations or stations before vehicles” problem.
Lower Transition Risk
The ability to revert to 100% diesel is commercially valuable while hydrogen supply is sparse. Operators can trial a new fuel without accepting the range risk of a hydrogen-only vehicle. It also allows a converted truck to work outside the hydrogen network when necessary.
This flexibility is precisely why dual fuel is best understood as a bridge. It begins creating hydrogen demand, driver experience, servicing capability and refuelling knowledge before zero-emission heavy vehicles are widely available at acceptable cost.
Creating a New Product and Capability
Creating a New Product and Capability
The programme has produced more than internal emissions savings. Change Fuel Technologies now offers conversion capability to other transport operators, turning HWR’s operating experience into a potential commercial product. The company has demonstrated that the system can be adapted to several makes, engine configurations and vocational duties rather than being tied to one prototype.
This creates New Zealand capability in integration, controls, certification, installation, safety systems, data and maintenance. It may also allow customers to purchase a lower-carbon freight service. Change Fuel Technologies describes this as moving the conversation beyond transport price alone by giving customers a measurable way to reduce supply-chain emissions.
Building an Evidence Base
Building an Evidence Base
New Zealand trials provide practical operating evidence, while verified customer payback and fleet-wide savings still require project-specific data.
HWR’s diverse fleet trials have generated practical information about fuel displacement, tank sizing, payload, refuelling and performance on New Zealand roads. That reduces uncertainty for subsequent vehicle owners, funders, regulators and hydrogen suppliers. The programme has also shown where the proposition is strongest: high-use, heavy vehicles able to return regularly to a known fuel source.
What Has Not Yet Been Publicly Demonstrated
The environmental and operational benefits are better documented than the financial return. The public EECA case study reports a commercial structure of NZ$150,000 for the hydrogen kit plus an annual lease of NZ$20,000 over six years, with installation, maintenance, fairings and covers additional. Public funding can cover part of qualifying conversion costs through the Low Emissions Heavy Vehicle Fund.
However, HWR has not published enough information to calculate a verified customer payback period or fleet-wide operating-cost saving. A robust calculation would require actual kilometres in dual-fuel mode, hydrogen and diesel consumption, delivered fuel prices, maintenance, conversion downtime, financing, residual value and any premium paid by customers for lower-emission freight.
The published figure showing a 17% reduction in fuel used per kilometre across HWR’s 2024 New Zealand operations should not be attributed solely to dual-fuel trucks. HWR’s report says that result reflected broader operational-efficiency improvements, while changes in business activity and the group structure also influenced its absolute emissions.
There is also a practical dependency on hydrogen availability. A truck running on diesel because the hydrogen station is unavailable retains operational continuity but receives no dual-fuel emissions benefit. The utilisation of production and refuelling assets will strongly influence the delivered hydrogen price and the programme’s eventual commercial return.
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A Practical Transition Rather Than the Final Destination
A Practical Transition Rather Than the Final Destination
Dual fuel offers an incremental emissions-reduction pathway while zero-emission vehicles and hydrogen infrastructure continue to develop.
HWR’s dual-fuel conversions have demonstrated a credible way to reduce emissions from difficult heavy-transport duties using assets already in service. The programme has operated across milk collection, freight, aggregate haulage and concrete delivery, with reported diesel and tailpipe-carbon reductions of around 30% in ordinary dual-fuel operation and higher results possible in suitable conditions.
The business benefits are equally practical: existing fleet value is preserved, productivity and payload are maintained, refuelling is fast, and diesel fallback protects operations while hydrogen infrastructure develops. HWR has also created a conversion business, built local technical capability and begun linking vehicle demand with future hydrogen production and distribution.
The technology does not remove diesel or tailpipe emissions, and a proven financial payback has not yet been disclosed publicly. Its economic case will depend on conversion cost, vehicle utilisation, hydrogen price, reliable fuel access and the value customers place on lower-emission freight.
That balanced assessment is also the reason the programme matters. Rather than waiting for a perfect zero-emission truck and a complete national fuel network, HWR has tested an incremental approach on real commercial work. Dual fuel can deliver meaningful reductions now, develop the market and retain operating flexibility—while the industry works toward vehicles and fuels capable of eliminating the remaining emissions.