Natural gas combined-cycle electricity
Natural-gas combined-cycle electricity represents approximately:
What this means
These values describe electricity generated by a natural-gas combined-cycle power plant on a lifecycle basis. They are not dollar estimates and do not include household appliance manufacture or use beyond the electricity quantity itself. For a liquid-fuel example, see diesel.
Formal measurement basis
| Item measured | Natural-gas combined-cycle electricity |
|---|---|
| Formal functional unit | 1 kWh electricity generated |
| Reader-facing scale | One average U.S. household day of electricity, shown as 29.6 kWh |
| Primary boundary | Natural-gas supply chain plus NGCC power generation |
| Secondary boundary | Plant-generation-only emissions where source supports it |
| Source review | Version 2 source review, 2026 |
Full measurement table
| Physical quantity | Working value | Literature range | Unit | Boundary note |
|---|---|---|---|---|
| Lifecycle GHG | 0.428 | 0.403–0.513 | kg CO₂e / kWh | Natural-gas supply chain + NGCC generation |
| Lifecycle GHG | 0.944 | 0.888–1.131 | lb CO₂e / kWh | Converted from kg/kWh |
| Household-day GHG | 27.9 | 26.3–33.5 | lb CO₂e / average household day | Same lifecycle value scaled to 29.6 kWh/day |
| Upstream natural-gas supply GHG | ~0.027 | Low-leakage point estimate pending range hardening | kg CO₂e / kWh | Pre-combustion gas supply-chain estimate; methane leakage assumption should be verified |
| Water and NOx | Not selected | Plant-dependent | varies | Cooling system and emissions controls matter |
What is included
The lifecycle GHG value includes upstream natural-gas supply-chain effects and power-plant generation. Upstream gas stages may include production, gathering, processing, transmission, storage, and distribution depending on the source.
What is excluded
- Household appliance manufacture or use beyond electricity consumed
- Transmission and distribution losses unless a source explicitly includes them
- Plant construction unless included by the cited LCA
- Dollar conversion of climate, air quality, or health effects
Why values vary
Values vary by plant efficiency, methane leakage assumptions, gas source, time period, generation technology, plant controls, and whether the boundary is plant-only or lifecycle. The upstream estimate is retained as a working value but should be hardened into a range because methane leakage is a major source of LCA variation.
Source notes
The working value is anchored to NETL lifecycle analysis. The range uses UNECE lifecycle estimates for natural-gas combined-cycle electricity. Household-day values are direct conversions from EIA's average residential electricity consumption value.
Sources
- National Energy Technology Laboratory, Life Cycle Analysis: Natural Gas Combined Cycle Power Plant. Used for: lifecycle NGCC GHG working value.
- United Nations Economic Commission for Europe, Life Cycle Assessment of Electricity Generation Options. Used for: lifecycle GHG range for NGCC generation.
- U.S. Energy Information Administration, How much electricity does an American home use?. Used for: 10,791 kWh/year average U.S. residential customer electricity use.
- National Renewable Energy Laboratory, Life Cycle GHG Emissions from Conventional Natural Gas. Used for: upstream natural-gas supply-chain estimate.
- NETL, Life Cycle Analysis of Natural Gas Extraction and Power Generation: U.S. 2020 Emissions Profile. Used for: supply-chain boundary support.