Natural Gas Generator Emissions Calculator

What this calculator measures

Estimate direct combustion CO2 in metric tonnes from electrical kWh, efficiency, and a natural-gas factor in kg CO2/MMBtu. Keep efficiency and factor on the same heating-value basis. This is not a lifecycle or regulatory inventory calculation.

Inputs and units

Use readings and ratings that describe the same equipment, operating interval, and measurement boundary. The sample entries are editable examples; they do not establish the specifications of your generator.

Calculation method

Electrical energy is rated kW multiplied by average load fraction and operating hours. Divide electrical kWh by efficiency as a fraction to obtain fuel-energy kWh. Convert fuel energy to MMBtu using 0.003412141633 MMBtu per kWh, then multiply by the chosen kg CO2/MMBtu factor. Finally divide kilograms by 1,000 to display metric tonnes.

The default factor is an editable example, not a measurement of your supplied gas. EIA publishes fuel factors using its stated conventions; use a factor compatible with the efficiency basis and reporting method you actually need.

Worked example

With a 100 kW rating, 50% average load, one operating hour, 40% efficiency, and 53.06 kg CO2/MMBtu, electrical production is 50 kWh. The estimate is approximately 22.631 kg CO2, or 0.0226 metric tonnes at the displayed precision. A result of 22.63 metric tonnes for those entries would be a unit error.

Limitations and checks

This estimates CO2 from fuel combustion only. It excludes upstream methane, construction, other greenhouse gases, and emissions during operating periods not represented by the entered energy and efficiency. Divide the unrounded total kilograms by delivered electrical kWh separately if you need kg CO2/kWh.

Zero or negative efficiency is invalid. The model assumes a representative positive efficiency; it cannot reproduce a nonlinear no-load fuel curve. Small events may require more precision than the four-decimal tonne display.

For a practical decision, keep the original readings, the generator model, the relevant manual or specification, and the assumptions alongside the result. A different load, site condition, rating basis, or unit convention can answer a different question even when the arithmetic is correct.

Sources and methodology

• EIA fuel CO2 coefficients

Publisher: CSP Digital Media Ltd. To report a formula, unit, or example error, contact us with the tool name, inputs, displayed result, and expected calculation.