In short. Temporary gas generation can make sense for long-duration rental where piped natural gas, LPG or a reliable gas supply is available and lower emissions or fuel cost matter. Feasibility starts with the fuel, not the generator: gas type, delivery pressure, available flow, duration and the temporary fuel infrastructure must all be confirmed. Gas engines also accept load steps less readily than diesel, so the load profile must suit them. Each requirement is screened against fuel and equipment.
Where gas rental is a realistic option
Diesel remains the default for temporary power in India because of its fuel availability, fast starting and strong load acceptance, which suit construction, shutdowns, emergencies and large motor loads. Gas becomes worth evaluating when a project runs for months near a city gas distribution network or an industrial gas connection, when emission restrictions limit diesel operation, when fuel cost over a long period outweighs higher equipment cost, or when noise and fumes near occupied buildings are a concern. Under air-quality action plans in some regions, diesel set operation can be restricted during pollution episodes; the temporary DG operating restrictions page covers that context. Gas rental equipment availability is limited compared with diesel, and we treat each enquiry as project screening rather than a stock item.
Six fuel questions come first
- What gas is available: piped natural gas, CNG cascades, LPG, or a biogas source?
- At what pressure is it delivered at the proposed connection point?
- What flow can the connection sustain continuously, and at peak?
- For how long will the supply be needed, and can it be contracted for that period?
- Which engine configuration is compatible with that gas composition and pressure?
- How will the temporary fuel line, regulation, metering and safety shut-off be installed and approved?
The gas network or temporary fuel system becomes part of the rental project. Without firm answers to these questions, there is nothing to size.
Gas flow: sizing the supply
Gas flow (Sm³/h) = electrical output (kW) / (electrical efficiency x gas lower heating value in kWh/Sm³)
Electrical output is the expected generator load, electrical efficiency is the gas-to-electricity efficiency of the set at that load from manufacturer data, and the lower heating value of natural gas is roughly 9 to 10 kWh per standard cubic metre depending on composition. As an illustration (illustrative), a 500 kW load on a set with 36 percent electrical efficiency using gas at 9.5 kWh/Sm³ needs about 500 / (0.36 x 9.5), roughly 146 Sm³/h, and more at part load where efficiency falls. That flow must be available at the required pressure without starving other users on the same connection. The natural gas generators page explains how gas quality affects engine rating.
Diesel and gas temporary power compared
| Factor | Diesel rental | Gas rental |
|---|---|---|
| Fuel logistics | Tanker delivery to any site | Needs a gas connection or bulk gas storage |
| Load acceptance | Large single steps accepted | Smaller steps; load usually applied in stages |
| Starting time | Seconds | Longer, with gas train purging and checks |
| Emissions and odour | Higher particulate and NOx; CPCB norms apply | Lower particulate; NOx depends on engine tuning |
| Fuel cost over long duration | Usually higher per kWh | Often lower where gas is available on contract |
| Equipment availability | Wide | Limited; confirmed per project |
Load behaviour on gas engines
Lean-burn gas engines respond more slowly to sudden load than diesel engines because the air-fuel mixture and turbocharger must catch up. A step that a diesel set takes in one move may need to be split into several on a gas set to keep frequency within limits. Large motor starts, simultaneous restarts and emergency transfer are therefore harder on gas. For steady base loads such as a process plant on continuous duty, this matters little; for emergency standby duty it often rules gas out. Pairing a gas set with battery storage to absorb steps is one solution, described under BESS rental and hybrid temporary power.
Temporary fuel infrastructure and safety
A temporary gas installation needs a properly designed connection: isolation valve, pressure regulation to the engine’s requirement, metering, filtration, flexible connection to the set, and an emergency shut-off that operates on fire detection or gas leak alarm. Pipework routes must be protected from vehicles and work activity, and the set’s enclosure needs ventilation and gas detection. The gas utility or supplier and the site’s safety authority usually must approve the arrangement. Commissioning should verify pressure at full flow, regulator response to load steps, leak tightness and the shut-off function before the set carries load.
Long duration means continuous duty
Gas rental is chosen almost always for long hires, and long hires turn the set into the operating power plant. Spark plugs, oil and filters need servicing on the engine’s interval, oil analysis is more important than on diesel standby duty, and the service plan must coordinate with gas supply so that maintenance and fuel logistics do not conflict. Where permanent gas generation is being considered after the temporary phase, the gas power systems section covers the options.
Common mistakes
- Choosing gas before confirming the supply. The set arrives and the connection cannot deliver the flow at the required pressure.
- Applying diesel-style load steps to a gas engine. Frequency falls out of limits and the set trips on underfrequency.
- Using gas rental for emergency standby. Slower starting and step acceptance leave critical loads unsupplied for longer than planned.
- Installing temporary pipework without approval and shut-off. The project is stopped by the safety authority or, worse, a leak goes undetected.
What to send us
Send the gas type and supplier, the available pressure and flow at the proposed connection point, the load profile with its largest steps, the project duration and daily hours, and the reason gas is preferred over diesel. A photograph or drawing of the gas connection and the proposed set position helps us assess the temporary fuel arrangement. Use the application engineering enquiry, since every gas rental starts as a screening exercise.
Questions engineers ask
Can a diesel rental set run on gas?
Not directly. A standard diesel set needs a dual-fuel conversion kit to substitute part of its diesel with gas, and the substitution rate depends on load and engine. Dual-fuel conversion is rarely worthwhile for a short rental; it is discussed on the dual-fuel pages for permanent sets.
Is LPG a practical fuel for temporary generation?
For smaller sets and sites without piped gas, LPG from bulk storage can work, but vaporisation capacity in cool conditions and storage approvals limit the scale. For large loads the volume of LPG and the storage safety requirements usually make piped natural gas or diesel more practical.
How much gas does a 1 MW temporary set use?
At full load and typical efficiency of 37 to 40 percent, roughly 260 to 290 Sm³/h of natural gas, rising at part load. Confirm against the specific engine’s data and the actual gas heating value from the supplier.
Do gas generators need CPCB compliance?
Gas-based gensets have their own CPCB emission limits, separate from diesel norms. Confirm that the rental set has the applicable type approval and that the site’s consent conditions permit its operation.
Generators by rating
- Under 15 kVA generators
- 15–50 kVA generators
- 50–125 kVA generators
- 125–250 kVA generators
- 250–500 kVA generators
- 500–1000 kVA generators
- 1–2 MVA generators
- 2 MVA and above generators
Technical content reviewed by Srinivas Reddy, Managing Partner, Reddy Generators. Last updated 19 October 2026.