Lifecycle emissions
Total greenhouse gas emissions of a product or power source across its full life, from raw material extraction and manufacturing through operation to decommissioning.
Lifecycle assessment (LCA, ISO 14040/14044) counts emissions from cradle to grave rather than only at the point of combustion. For electricity it includes mining, fuel processing and transport, plant construction, operation and maintenance, and dismantling, divided by lifetime output.
Representative medians (IPCC AR5 WGIII Annex III; UNECE 2021, gCO2e/kWh): coal 820–1,000, gas CCGT 430–490, gas with CCS 130–170, utility PV 20–50, CSP 25–30, onshore wind 8–12, offshore wind 12–14, nuclear 5–12, hydro 6–24 (reservoir hydro in tropical regions can be much higher because of flooded biomass decay).
For fossil plants, upstream supply chains add 10–25% on top of stack emissions, and more where methane leakage is high. For renewables, nearly all emissions are embodied in manufacturing, so results depend on the electricity mix of the factory and fall over time as supply chains decarbonise. Lifecycle values are the right basis for technology comparisons; direct values are used in emissions trading and Scope 1 inventories.
Related terms
All terms →- Carbon intensity of electricity
The mass of CO2 (or CO2e) emitted per unit of electricity generated or consumed, usually expressed in grams per kilowatt-hour (gCO2/kWh).
- Energy payback time
The time an energy system must operate to generate as much energy as was used to manufacture, install and decommission it.
- Methane leakage
Unintended release of methane from oil, gas and coal supply chains through leaks, venting and incomplete flaring, often expressed as a percentage of gas produced.
- Scope 3 emissions
All other indirect emissions in an organisation’s value chain, upstream and downstream, not covered by Scope 1 or Scope 2.
- EROI (Energy Return on Investment)
The ratio of usable energy delivered by an energy source over its lifetime to the energy invested to obtain and deliver it.