How Much Does It Cost To Run A Generator On Natural Gas?

During a power outage, a natural gas generator is your best friend. Without access to electricity from the grid, we have to burn natural gas to generate electricity. We looked into how much does it cost to run a generator on natural gas.

The running cost of a generator depends on 3 primary factors:

1. Size of a generator. A 20,000W generator will obviously burn more natural gas than a 5,000W generator. You can use the natural gas running cost calculator to determine how much does running a generator cost per hour. We have also calculated generator gas consumption tables further on.
2. Price of natural gas in your area. The cost of natural gas generator fuel consumption per kWh is correlated with the price of natural gas. Example: Let’s say that we have a generator that burns natural gas at a cost of $20 per thousand cubic feet vs the same generator that burns natural gas at a cost of $10 per thousand cubic feet. $20 natural gas cost generator will have twice the running cost per kWh than the $10 natural gas cost generator.
3. Generator running load. Generators are run at anywhere between 0% and 100% of their maximum output wattage. If you run your generator at 60% load, the running costs will be higher than if you were to run it at 40% load.

If we know all these parameters, we can adequately calculate how much does it cost to run your natural gas generator per hour, per day, per week, or per month.

Running a generator on natural gas will cost you anywhere from $0.02 to $2.41 per hour (1,000W 25% load generator to 30,000W 100% load, respectively). It will consume anywhere from 1.86 ft³ to 222.90 ft³ of natural gas per hour.

We have designed a Gas Generator Fuel Consumption Calculator that estimates the running costs of any natural gas generator. You just enter the size of the generator, price of natural gas, and average load, and the calculator returns how many US dollars per hour worth of natural gas such a generator is consuming.

Further on, we have calculated the running costs of 1,000W, 2,000W, 3,000W, 4,000W, 5,000W, 6,000W, 7,000W, 8,000W, 10,000W, 12,000W, 15,000W, 20,000W, 25,000W, and 30,000W natural gas generators at average price and at 1/4, 2/4, 3/4 and full loads.

First of all, however, we need to look at how to calculate the running costs with a gas generator fuel consumption formula (this derivation is a bit mathematical, you can just skip to the easy-to-use calculator and calculated tables if you wish):

Gas Generator Fuel Consumption Formula

With this formula, we can determine how much natural gas does a generator use per hour. On top of that, if we know the price of natural gas, we can also calculate the dollar amount of natural gas we use to operate our generator per hour.

Note: By extension, we can calculate the running fuel usage and cost per day, week, and month.

Let’s derive the natural gas generator fuel consumption using a 10,000W generator example. Let’s also take the 2020 average residential price of natural gas ($10.83 per 1,000 cubic feet, according to Statista).

How much natural gas do we need to keep a 10,000W generator running at full load for 1h?

We will need an equivalent of 10 kWh (kilowatt-hour) of natural gas. According to EIA, we need 7.43 cubic feet of natural gas to produce 1 kWh (74.3 cubic feet for 10 kWh).

Note: If you wondered about natural gas generator fuel consumption per kWh, it’s 7.43 ft3 of natural gas or about $0.08 per kWh. That’s lower than the national average cost of electricity ($0.1319/kWh) by a hefty margin.

If 1,000 cubic feet cost $10.83 then 74.3 cubic feet cost:

10,000W Generator Running Cost = $10.83 × (74.3 cubic feet ÷ 1,000 cubic feet)

= $0.80 per hour

General Fuel Consumption Formula

Here is a formula for calculating gas generator fuel consumption:

Fuel Consumption Per Hour = Max. Wattage × Load × 7.43 Cubic Feet Of Natural Gas ÷ 1,000

We know the max. wattage of the generator, as well as load. We know that we need 7.43 cubic feet of natural gas to produce 1 kWh of electricity. The factor ‘1,000’ is there to convert Wh into kWh (watt-hours into kilowatt-hours).

With this equation, we can calculate how much fuel does a gas generator consume per hour.

Example: Let’s say we have a 5,000W generator and we run it at 0.6 load (that’s 60% of max. load). How much natural gas does such a gas generator consume per hour? Let’s calculate:

Fuel Consumption Per Hour = 5,000W × 0.6× 7.43 Cubic Feet Of Natural Gas ÷ 1,000 = 22.29 Cubic Feet Of Natural Gas

That means that a 5,000W generator running at 60% load will consume 22.29 cubic feet of natural gas per hour. That’s:

• 534.96 ft³ per day.
• 3,744.72 ft³ per week.
• 16,048.80 ft³ per month.

Now that we know how much natural gas does a generator consume, we can also calculate how much does running such a generator cost in US dollars:

Generator Running Cost Formula

If we know how many cubic feet of natural gas a generator will burn through, we can easily calculate how much that quantity of natural gas costs.

We can use the 2020 average natural gas price for residential users:

1,000 cubic feet of natural gas costs $10.83.

If we use the quantities of consumed natural gas from the previous example, we can determine that a 5,000W generator running on 60% load costs:

• $0.24 per hour.
• $5.79 per day.
• $40.56 per week.
• $173.81 per month.

The general formula for calculating the running cost of a generator looks like this:

Running Cost  = Quantity Of Gas Consumed (in ft³) × Price Of Natural Gas (in 1,000 ft³) ÷ 1,000

We divide by 1,000 because the price of natural gas is given in US dollars per 1,000 cubic feet. Let’s solve an example to illustrate how this equation works.

Example: How much does it cost to run a whole house generator on natural gas? Let’s say that such a whole-house generator burns through 1,200 ft³ of natural gas per day. Let’s calculate the running cost per day:

Running Cost = 1,200 ft³ of natural gas × $10.83 per 1,000 ft³ of natural gas ÷ 1,000 = $13,00/Day

Such a whole-house generator will cost $13,00 per day to run.

Now that we have the theory with examples covered, let’s look at how you can easily calculate how much does it cost to run a generator on natural gas yourself with a help of a calculator:

Gas Generator Fuel Consumption Calculator

This calculator will calculate how much does it cost to run a generator on natural gas per hour. You have to input the maximum running wattage of the generator (in watts), the price of natural gas (average is $10.83 per 1,000 cubic meters of natural gas, and the average load (if you have a 5,000W generator and use only 3,000W of power, that’s a 0.6 or 60% load, for example).

You can play around with numbers, this consumption calculator will dynamically calculate the resulting running costs per hour:

Calculated Table Of Running Costs For Generators On Natural Gas

For running costs calculation, we used the 2020 national average residential natural gas price of $10.83 per 1,000 cubic feet.

Notice: This is a big table. You can scroll down and use the slider to slide it from left to right:

Generator Size:	1/4 Load Consumption	1/4 Load Running Cost	2/4 Load Consumption	2/4 Load Running Cost	3/4 Load Consumption	3/4 Load Running Cost	Full Load Consumption	Full Load Running Cost
1,000W	1.86 ft3/h	$0.02/h	3.72 ft3/h	$0.04/h	5.57 ft3/h	$0.06/h	7.43 ft3/h	$0.08/h
2,000W	3.72 ft3/h	$0.04/h	7.43 ft3/h	$0.08/h	11.15 ft3/h	$0.12/h	14.86 ft3/h	$0.16/h
3,000W	5.57 ft3/h	$0.06/h	11.15 ft3/h	$0.12/h	16.72 ft3/h	$0.18/h	22.29 ft3/h	$0.24/h
4,000W	7.43 ft3/h	$0.08/h	14.86 ft3/h	$0.16/h	22.29 ft3/h	$0.24/h	29.72 ft3/h	$0.32/h
5,000W	9.29 ft3/h	$0.10/h	18.58 ft3/h	$0.20/h	27.86 ft3/h	$0.30/h	37.15 ft3/h	$0.40/h
6,000W	11.15 ft3/h	$0.12/h	22.29 ft3/h	$0.24/h	33.44 ft3/h	$0.36/h	44.58 ft3/h	$0.48/h
7,000W	13.00 ft3/h	$0.14/h	26.00 ft3/h	$0.28/h	39.01 ft3/h	$0.42/h	52.01 ft3/h	$0.56/h
8,000W	14.86 ft3/h	$0.16/h	29.72 ft3/h	$0.32/h	44.58 ft3/h	$0.48/h	59.44 ft3/h	$0.64/h
10,000W	18.58 ft3/h	$0.20/h	37.15 ft3/h	$0.40/h	55.73 ft3/h	$0.60/h	74.30 ft3/h	$0.80/h
12kW	22.29 ft3/h	$0.24/h	44.58 ft3/h	$0.48/h	66.87 ft3/h	$0.72/h	89.16 ft3/h	$0.97/h
15kW	27.86 ft3/h	$0.30/h	55.73 ft3/h	$0.60/h	83.59 ft3/h	$0.91/h	111.45 ft3/h	$1.21/h
20kW	37.15 ft3/h	$0.40/h	74.30 ft3/h	$0.80/h	111.45 ft3/h	$1.21/h	148.60 ft3/h	$1.61/h
25kW	46.44 ft3/h	$0.50/h	92.88 ft3/h	$1.01/h	139.31 ft3/h	$1.51/h	185.75 ft3/h	$2.01/h
30kW	55.73 ft3/h	$0.60/h	111.45 ft3/h	$1.21/h	167.18 ft3/h	$1.81/h	222.90 ft3/h	$2.41/h