목적 (Purpose)
Defines the types, source attributes, and assignment of the emission factors used in calculation. How a factor enters the formulas is covered in Scope 1·2 배출량 산정 방법론 (Scope 1 & 2 Calculation Methodology); this document describes the concept and classification only and does not present or recommend any specific factor value.
What an Emission Factor Is
An emission factor is the greenhouse-gas emission per unit of activity (fuel L, electricity kWh, material kg, etc.). Emission = activity × factor. Each factor has an input unit and output unit; the activity is converted to the factor's input unit before applying it.
Factor Types
Per-gas factors (CO2·CH4·N2O), summed to CO2eq via GWP; a single CO2eq factor (chiefly electricity) giving CO2eq in one multiply; calorific factors (GCV·NCV) converting fuel to energy (emission uses NCV); and an oxidation factor for stationary-combustion CO2 (default 1).
Location-based vs Market-based
Electricity factors are of two kinds — location-based (grid-average) and market-based (contractual instruments such as RECs, PPAs, green tariffs). Both are applied to the same usage and reported side by side.
Attributes & Sources
Each factor carries attributes: applicable category/energy source, country, publishing organization, revision year, and confidence tier. Factors come from recognized sources (e.g., national GHG inventory bodies, IEA, IPCC, ecoinvent, EPA, DEFRA); values differ by source and revision year. This document explains that the source/attribute scheme exists but prescribes no value.
Assignment & Change
A source is assigned a factor matching its conditions (country, category, energy source, period); users can select/override factors, and corporation-level rules can steer auto-assignment. Electricity factors route by location/market. Factor changes are recorded for audit.
No Value Recommendation
This knowledge base does not recommend or prescribe specific emission-factor values. Values follow the customer's regulatory/verification requirements and chosen sources; only method and classification are documented here.
Basis & Standards
표준 정본 목록: GHG Protocol 및 Scope 분류 기준. Factor tiers/selection follow GHG Protocol and the Scope 3 Technical Guidance; sources (IPCC, IEA, national inventories, ecoinvent) are cited as types, not values.