Technical challenge
Substitution varies with engine load, speed, route and control strategy, so representative operating-cycle data is essential.
Introduction
Hydrogen-diesel Dual-fuel Conversions.
Assess whether displacing a portion of diesel with hydrogen can reduce emissions in suitable existing engines and operating cycles.
Dual-fuel systems introduce hydrogen into a diesel engine while retaining diesel for ignition and often for operation outside suitable load conditions.
A credible conversion case requires measured substitution, verified emissions, safe onboard storage and no compromise to engine reliability or compliance.
The Challenge
Define the service problem before selecting technology.
Existing heavy fleets, long asset lives and difficult-to-electrify operations create interest in transitional emissions-reduction options.
Business challenge
Reliability, utilisation, logistics, asset life and future demand must be translated into a commercial requirement that can be compared consistently across competing solutions.
Human challenge
The selected pathway must be understandable, maintainable and safe for the people operating it. Training, access, disruption, noise, local air quality and confidence in support can be as important as equipment performance.
The Goal
Turn the challenge into measurable project requirements.
The goal is to deliver the required service with a practical combination of efficiency, electrification, renewable energy, storage, hydrogen and operational controls—not to maximise any one technology.
Information to establish early
Record engine family, certification, load profile, diesel use, route, available installation space, hydrogen access and remaining asset life.
- Define the required output, operating pattern and acceptable interruption.
- Separate peak capacity from total daily or annual energy.
- Record present costs, constraints and service problems.
- Identify safety, consent, access and workforce requirements.
- Agree measurable performance, emissions and commercial outcomes.
Understanding the Technology
Follow the complete energy and hydrogen pathway.
The conversion includes certified storage, pressure regulation, injection and controls, engine integration, monitoring, refuelling and workshop procedures.
01
Primary input
Identify the electricity, renewable resource, delivered fuel, water or existing process input and when it is available.
02
Hydrogen supply
Define production or delivery, hydrogen quality, pressure, usable kilograms, storage duration and replenishment.
03
Conversion and control
Select equipment around useful output, response, efficiency, operating hours, redundancy and integration with existing assets.
04
Final service
Measure the useful transport, electricity, heat or industrial service actually delivered to the user.
Important: equipment ratings describe only part of a solution. The system boundary must include energy supply, conversion losses, auxiliaries, storage, delivery and the operating reserve.
What are the Options?
Compare hydrogen with direct electrification and established alternatives.
Where hydrogen may fit
A conversion may have value where suitable sustained high-load operation, accessible hydrogen and a well-supported certified system allow meaningful diesel displacement.
Where another pathway may be better
Full electrification, vehicle replacement, renewable diesel, efficiency measures or operational changes may deliver greater or simpler reductions.
Decision principle: compare complete systems against the same operating requirement, site conditions, safety obligations, emissions boundary and lifecycle period.
Typical Use Cases
Look first for demanding applications with a clear service value.
Existing heavy fleets, long asset lives and difficult-to-electrify operations create interest in transitional emissions-reduction options.
Milk and bulk tankers
High annual kilometres and return-to-base patterns can support predictable refuelling and measurable diesel displacement.
Concrete and construction
Heavy vehicles with difficult electrification pathways may use conversion as an interim emissions-reduction step.
Freight fleets in transition
Conversion can retain newer diesel assets while organisations prepare for zero-emissions replacements and infrastructure.
Solution Size
Size the service, energy pathway and reserve together.
Substitution varies with engine load, speed, route and control strategy, so representative operating-cycle data is essential.
EECA describes conversion equipment with five tanks holding about 23 kg hydrogen, adding about 960 kg, and refuelling in around seven minutes.
| Measure | Why it matters | Evidence to collect |
|---|---|---|
| Maximum output | Sets peak equipment and connection capacity. | Measured peaks, route demand, starting loads or process rate. |
| Useful energy | Determines fuel, storage and replenishment. | Hourly, daily, seasonal or route-level consumption. |
| Operating window | Shapes utilisation, recovery and maintenance. | Shifts, dwell time, event duration and annual hours. |
| Reserve and redundancy | Protects service through credible failures or delays. | Criticality, outage tolerance, alternative supply and resupply time. |
These measures structure an initial conversation; they are not a design or equipment recommendation.
Benefits and Limitations
Understand both the potential value and the hard constraints.
Potential benefits
Potential value includes using an existing asset and reducing a portion of diesel consumption during suitable operating periods.
Limitations to resolve
Partial substitution, certification, warranty, variable real-world results, storage packaging and continued diesel dependence must be explicit.
Practical Considerations
Plan the site, supply chain and operating organisation.
Hydrogen supply must match daily route demand and onboard storage without materially reducing payload or availability.
Site and access
Confirm space, access, foundations, ventilation, weather exposure, security, vehicle movements and future expansion.
Operations
Define trained roles, monitoring, inspections, planned maintenance, spare parts, alarms and emergency response.
Supply resilience
Test production or delivery capacity, hydrogen quality, refill intervals, route disruption, reserve and recovery after an event.
Safety
Use application-specific design, controls and competent advice.
Vehicle modification, pressure systems, crashworthiness, workshops, refuelling and operator training require formal approval and competent providers.
Hazard controls
Address loss of containment, ignition, ventilation, pressure, impact, electrical hazards, hazardous areas and emergency isolation.
People and procedures
Define competence, training, inspection, permits, signage, access control, incident response and communication with emergency services.
Site-specific compliance
Applicable requirements depend on quantities, pressure, equipment, location and activity. Separation distances and approvals cannot be selected from a generic web page.
Commercial Considerations
Compare the cost of delivering the required service.
Use verified fuel displacement and emissions data, conversion cost, downtime, remaining vehicle life and hydrogen price in the business case.
Capital
Equipment, civil works, connection, storage, controls, consent, engineering and contingency.
Operating
Electricity, hydrogen, delivery, labour, maintenance, inspections, consumables and replacement parts.
Utilisation
Annual output, shared infrastructure, contracted demand and the effect of idle capacity on unit cost.
Value and risk
Avoided downtime, emissions, noise, constrained infrastructure, fuel volatility, residual value and technology maturity.
New Zealand Examples
Use verified local evidence and state project maturity clearly.
New Zealand hydrogen activity includes operational trials, demonstrations, commercial proposals and developing supply chains. Examples added to this page should identify what operated, where, for how long, the measured output and the source of the claim.
Operating conversions
HW Richardson mixed heavy fleet
EECA reports conversions of milk tankers, freight and bulk-haul trucks and a concrete truck. Six were co-funded and four more funded internally.
Read the EECA trial resultsMeasured trial result
Approximately 30% diesel reduction
EECA reports comparable vehicle performance and an operator estimate of about 30% less diesel, while noting dual fuel only partially reduces emissions and is not zero-emissions transport.
Review the emissions contextApplication Evidence
What these examples establish
This is a real NZ transition pathway with measured operation. The remaining diesel use, conversion cost, added mass, hydrogen source and long-term vehicle strategy must stay visible.
Project Process
Progress from interest to an evidence-based proposal.
01
Discovery
Confirm the service problem, stakeholders, timing, present system and reasons for considering change.
02
Measure
Collect operating data, site constraints, supply information, safety requirements and commercial assumptions.
03
Compare
Screen credible pathways on the same system boundary and document exclusions, sensitivity and uncertainty.
04
Develop
Complete concept design, stakeholder engagement, approvals, procurement, implementation and performance verification.
Suitable Products
Build the system from compatible supply, storage and conversion components.
Product suitability depends on the measured requirement and complete system design. Review the current ranges as starting points rather than standalone recommendations.
Hydrogen supply and production
Review electrolyser and supply options around required quality, production rate and operating schedule.
Explore product rangesStorage and delivery
Match usable kilograms, pressure, refill route, transport and reserve to the operating requirement.
Explore storage productsFuel-cell power and integration
Coordinate continuous power, transient response, batteries, inverters, controls and monitoring.
Explore power systemsFAQ
Common early questions.
Is hydrogen automatically the best low-emissions option?
No. Full electrification, vehicle replacement, renewable diesel, efficiency measures or operational changes may deliver greater or simpler reductions. The correct comparison uses the same final service, site conditions, reliability and lifecycle boundary.
What information is needed before selecting equipment?
Record engine family, certification, load profile, diesel use, route, available installation space, hydrogen access and remaining asset life.
Where can hydrogen add value?
A conversion may have value where suitable sustained high-load operation, accessible hydrogen and a well-supported certified system allow meaningful diesel displacement.
What usually has the greatest effect on project cost?
Use verified fuel displacement and emissions data, conversion cost, downtime, remaining vehicle life and hydrogen price in the business case.
Can this page be used to determine safety distances?
No. Required controls and separation distances depend on the actual inventory, pressure, equipment, activity and site. Use current requirements and appropriately competent project specialists.
Scope and Limitations
Use this page for orientation, not final design or professional advice.
This material is general information for early customer and project conversations. It does not replace engineering, financial, legal, safety, environmental or regulatory advice. Technology performance, prices, hydrogen availability, standards and legal requirements change; verify current information for the actual New Zealand site and proposed activity.
Further Reading
Continue with authoritative and current information.
Project Support
Define the requirement before selecting equipment.
Share the operating requirement, location, timing and constraints so the next questions and evidence can be identified.