Choosing the fuel for a generator set is not a brand preference: it defines available runtime autonomy, supply logistics, cost per kWh generated, the maintenance regime and installation conditions. This is the comparison we apply when recommending a unit.
Diesel: the industrial standard
Diesel dominates emergency and heavy-duty generation for three reasons: mechanical robustness, high energy density (more kWh per liter stored) and fuel availability across the whole country, including remote areas. Modern diesel engines deliver power ranges from about 20 kVA to more than 2,000 kVA per unit.
Its weak point is operational handling: stored diesel degrades over time (microbial growth, water and sediment), so emergency systems that run infrequently require fuel polishing and rotation plans, plus periodic load-bank testing.
Gasoline: small power ratings and portability
Gasoline generator sets cover the portable range, typically below 10-15 kVA. They are cheaper to acquire, lightweight and suited to small loads and occasional use: tools, small businesses, household contingencies.
They are not an industrial solution: higher specific fuel consumption, shorter engine life under intensive use and storage risk (gasoline is more volatile and degrades faster than diesel). If the need is continuous or exceeds household loads, the correct reference is diesel or gas.
Natural gas: continuous operation with grid supply
Natural gas generator sets are the competitive option when the site has a gas grid connection: continuous fuel with no tanks or refueling logistics, lower particulate-matter and CO₂ emissions per kWh, and lower noise levels compared to an equivalent diesel unit.
Its constraint in Colombia is structural: they depend on gas grid availability and pressure, and in supply-restriction contexts — such as the gas deficit episodes declared by the regulator — their use can be limited precisely when it is most needed. For pure emergency applications, diesel keeps the advantage of stored autonomy.
Comparison table
- Typical power: gasoline < 15 kVA; diesel 20 kVA to +2,000 kVA; gas 30 kVA to +1,000 kVA.
- Autonomy: diesel depends on tank size (hours to days); gasoline limited by storage safety; gas continuous if there is grid supply.
- Cost per kWh: natural gas generally the lowest where there is grid supply; diesel intermediate; gasoline the highest.
- Maintenance: gasoline and gas with spark plugs and shorter intervals; diesel with longer intervals but requires stored-fuel management.
- Recommended use: gasoline for small contingencies; diesel for emergency power and industry; gas for continuous operation or cogeneration with reliable gas supply.
The decision rule
If the application is emergency power (the generator kicks in when the grid fails), diesel is almost always the answer because of its stored autonomy. If it is continuous operation or prime power with gas available, natural gas reduces energy cost and emissions. If the load is small and the use occasional, gasoline is enough.
In critical operations with high consumption, the trend is to combine both: fast-start diesel backup plus gas generation for peak hours or extended continuity, an architecture that also diversifies fuel-supply risk.
