In short. Dual-fuel suitability depends on engine model and condition, duty profile, site gas infrastructure and safety design. A structured assessment avoids converting sets that cannot deliver the expected substitution.
Assessment steps
- Engine: model, age, hours, condition, compression, injection system.
- Duty: prime, continuous or standby; typical load percentage and run hours.
- Gas: source, pressure, quality, storage and delivery reliability.
- Site: space, ventilation, hazardous-area layout.
- Controls and integration: genset controller and conversion kit compatibility.
- Approvals: local requirements.
- Economics: fuel savings versus capital and maintenance.
Scoring table (illustrative)
| Factor | Favourable | Unfavourable |
|---|---|---|
| Run hours | Many hours per year | Rare standby |
| Load | Steady and moderate to high | Light and variable |
| Gas | Pipeline or reliable supply | Uncertain delivery |
| Engine | Good condition | Worn or unreliable |
Economics
Annual saving ≈ diesel litres replaced × diesel price − gas cost − added maintenance
Check payback with realistic substitution rates, not the maximum. See performance and substitution.
Outcome options
- Convert as assessed.
- Overhaul first, then convert.
- Choose another route. See RECD vs dual fuel vs replacement.
Illustrative example
A set with 3,000 hours per year on steady 60 percent load, with a gas pipeline at the site boundary, scores well. A set used 50 hours per year does not, and its payback would be long.
Engine factors in more detail
| Factor | Why it matters for dual fuel |
|---|---|
| Compression ratio and turbocharging | Affect knock margin with gas |
| Injection system type | Determines how pilot diesel is controlled |
| Engine condition | Worn engines misfire or knock more readily |
| Cooling system capacity | Gas operation changes heat distribution |
| Maker’s support for conversion | Warranty and parts |
Site factors
- Distance to a gas source, and the pipeline or delivery arrangement.
- Pressure available at the site, and regulator needs.
- Storage for compressed or liquefied gas, if delivered.
- Generator room ventilation and layout.
- Distance from ignition sources and public areas.
Commercial factors
- Gas supply contract: price, minimum quantity, reliability.
- Conversion cost and who provides support.
- Insurance implications.
- Impact on engine warranty.
Run a trial if possible
A trial on one set, with measured fuel use at the actual load profile, replaces assumptions with data. A short trial can reveal an unexpected limit, for example poor performance at light load, before a fleet-wide commitment.
Decision record
Write down the assessment: inputs, assumptions, calculation, risks and the decision. If circumstances change, such as a change in gas price, the record allows quick review.
When the answer is no
If the assessment shows weak benefit, do not force it. Other routes may serve better. See replacement vs retrofit.
The master engineering question
If we were wrong about gas supply or load, would the project still pay?
What to send us
Send engine data, run hours and gas details. Send your application details.
Questions engineers ask
What is the main risk?
Assuming a higher substitution rate than the site delivers.
Does engine age matter?
Yes, condition and support for the kit.
Can I keep diesel backup?
Yes, dual fuel retains diesel capability.
Who approves?
Check the local authority.
General guidance only. Values illustrative.