Top 70+ Most Fuel Efficient Power Generators

When comparing power generators, specific fuel efficiency is one of the sometimes neglected features, often disguised in runtime at certain power levels, usually @25%, @50%, or @100% of nominal power with the fuel tank capacity being provided, as well.

We are binging You the list of the most fuel-efficient power generators with their efficiency provided in gallons and liters per kWh at a certain power level with other features provided as well.

Power Generators Features and Specifications

When looking for a new power generator, there are several important things to look for, including:

- Running and Starting power,

- fuel type, usually gas (gasoline, petrol), propane gas (LPG), natural gas, diesel,

- list of receptacles,

- is generator parallel ready or not,

- is generator inverter generator or not,

- fuel tank capacity,

- runtime on a single fuel tank,

- Carbon Monoxide sensor and other safety features like low-oil shut-off, power ready, overload protection and similar,

- noise levels,

- THD levels, etc.

Fuel efficiency is a very important feature and practically all manufacturers offer this information in the form of runtime at certain power loads and the fuel tank capacity, but they rarely state the specific fuel consumption.

Specific fuel consumption can be calculated using the following formula:

Specific Fuel Consumption = Tank Capacity (gal) / (P (kW) * T(h))

and is given in gal/kWh or liters/kWh.

For example, one of the most efficient power generators is WEN 56380i Portable Inverter Generator (Amazon link, link opens in the new window), which features 3400 Running Watts, 3800 Starting Watts, and 2.2 gallons (~8.32 l) fuel tank, and it can operate 8.5 hours @50% (1700W) of nominal power.

Thus, its specific fuel consumption is:

2.2 gallons / (1.7 kW * 8.5h) = 0.152 gal/kWh = 0.575 l/kWh

when the unit operates at 50% load (1700W).

However, there are several issues with calculating specific fuel consumption in this way:

- internal combustion engines are less efficient when operating at lower power levels. Thus, when comparing two power generators, compare them for the same load percentage (25%, 50%, 100%),

- we didn't calculate specific consumption of propane gas or natural gas, just gasoline,

- 2-stroke internal combustion engines are less fuel-efficient than 4-stroke engines, but they are also simpler and easier to maintain,

- most power generators support the use of gasoline mixed with up to 10% ethanol, but it is often unclear if the information about power generators are given for gasoline without ethanol or with 5% or 10% ethanol,

- in real life power generators don't provide just 25%, or 50% or 100% of their running watts - their loads change, often constantly. Inverter power generators with Eco modes and idle power control can be more efficient than non-inverter units when the load is from time to time 0 (zero) watts or very low.

Depending on the personal needs and requirements, other features are sometimes more important than specific fuel consumption, like THD levels (if You have to power sensitive electronics), noise levels (if You have to operate a power generator in a camp or urban environment), type and number of receptacles, fuel types (in emergencies, gasoline can be scarce, but the propane can be easily stored for longer periods of time), etc.

Thus, specific fuel consumption should be only one of the features when looking for a new power generator.

The following comparison table lists 70+ power generators with their most important features and specifications, specific fuel consumption included (power generators are ordered alphabetically):

Of course, there are many other power generators on the market as well.

As one can see, specific fuel efficiency ranges, depending on the load percentage, but the best units feature fuel consumption less than 0.2 gal/kWh (~0.76 l/kWh) almost regardless of their load.

But, such units often come with a very nice price tag, or they can use only gasoline and similar.

Again, when looking for a new power generator, specific fuel consumption is an important feature, just be sure to check other features as well, according to your own needs and preferences.

Note: when your new power generator arrives, be sure to thoroughly read the documentation that came with the unit in order to get accustomed to your new unit. And whatever You do, stay safe!