Gas-to-Power Calculator
Convert megawatts to MMBtu and Mcf per day, or find how many megawatts a gas stream can make.
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How to Use It
Pick a direction. Megawatts to gas shows how much fuel a power plant needs per day. Gas to megawatts shows how much continuous power a gas stream (for example, gas that would otherwise be flared) can make.
How This Calculator Works
The calculator runs these formulas in your browser:
- Megawatts to gas: MMBtu/day = MW × 1,000 × heat rate (Btu/kWh) × 24 ÷ 1,000,000
- Mcf/day = MMBtu/day ÷ (heat content in Btu/scf ÷ 1,000)
- Gas to megawatts: MMBtu/day = Mcf/day × heat content ÷ 1,000
- MW (continuous) = MMBtu/day × 1,000,000 ÷ heat rate ÷ 24 ÷ 1,000
- Energy per year (MWh) = MW × 8,760 hours
Default assumptions and sources
Default heat content is 1,036 Btu per standard cubic foot, close to the U.S. average in the EIA energy units page. Default heat rate is 9,000 Btu/kWh, between the averages for gas engines and simple-cycle turbines in the EIA Electric Power Annual, Table 8.2.
Worked example
A 10 MW plant at 9,000 Btu/kWh burns 10,000 kW × 9,000 × 24 ÷ 1,000,000 = 2,160 MMBtu a day. At 1,036 Btu/scf that is 2,160 ÷ 1.036 = about 2,085 Mcf a day. Going the other way, 1,000 Mcf a day of the same gas holds 1,036 MMBtu, enough for about 4.8 MW around the clock.
Limits
Heat rate and heat content must use the same basis (higher or lower heating value), or the answer is off by roughly 10%. Wellhead gas varies, flare volumes swing day to day, and engines lose efficiency at part load, so size a real project from a gas analysis and measured flow.
Common Questions
What heat content should I use?
Pipeline-quality gas is close to 1,000 to 1,050 Btu per standard cubic foot. Rich, unprocessed wellhead gas is often well above that. A gas analysis gives you the real number.
What is an Mcf?
One thousand standard cubic feet of gas. MMcf is one million. At about 1,036 Btu per cubic foot, one Mcf holds roughly 1.04 MMBtu.
Why does heat rate change the answer so much?
Heat rate is fuel in per unit of electricity out. A plant at 9,000 Btu/kWh burns about 29% more gas for the same power than one at 7,000 Btu/kWh.