목적 (Purpose)
Defines how Scope 1 (direct) and Scope 2 (indirect) emissions are calculated, at a level where a practitioner or verifier can follow and re-check the method. It describes the method and formulas only and does not recommend or prescribe any specific emission-factor value.
Calculation Overview
Emission data is organized as corporation → site → facility → emission source → monthly activity. Each source carries a Scope, category, energy source, and unit; the monthly activity records are what is actually calculated. Every activity's emission follows the general chain: activity value → normalize unit → apply emission factor (fuels first go through a calorific/energy step) → per-gas (CO2·CH4·N2O) × GWP, summed → convert to the reporting unit. Every multiplication is linear and uses high-precision decimals. A zero activity yields zero; a negative activity (corrections/credits) preserves its sign and yields a negative emission (not clamped to zero).
Direct Emissions
Scope 1 is emitted directly from sources the corporation owns or controls. The Scope 1 categories covered here are stationary combustion, mobile combustion, and process emissions. (Fugitive emissions such as refrigerant leakage are not split out as a separate category; they are modeled via process emissions or a single CO2eq factor.)
Stationary Combustion
Emissions from burning fuel. Fuel use is converted to energy via net calorific value (NCV), then per-gas emission factors and GWP are applied.
CO2eq = 연료사용량 × 순발열량(NCV)
× [ (CO2계수 × 산화계수 × GWP_CO2)
+ (CH4계수 × GWP_CH4)
+ (N2O계수 × GWP_N2O) ]- The oxidation factor applies to CO2 only, and defaults to 1 when not specified (complete oxidation assumed).
- Calculation always uses the net calorific value (NCV) (see "Calorific Value" below).
Mobile Combustion
Emissions from mobile combustion sources such as vehicles and equipment. The structure is the same as stationary combustion, but no oxidation factor is applied.
CO2eq = 연료사용량 × 순발열량(NCV)
× [ (CO2계수 × GWP_CO2) + (CH4계수 × GWP_CH4) + (N2O계수 × GWP_N2O) ]Process Emissions
Emissions from non-combustion processes such as chemical reactions. The emission factor is applied directly to the process activity with no energy (calorific) step — either per-gas factors or a single factor.
Indirect Emissions
Scope 2 covers indirect emissions from purchased electricity, steam, and heat. Grid electricity is computed by two methods presented side by side: location-based (grid-average factor × usage) and market-based (contractual-instrument factor × usage). Electricity energy is obtained by direct conversion between power units (e.g., kWh↔MWh) with no calorific step. Where market-based renewable procurement (REC/PPA) exceeds actual consumption, the net can compute as negative; the Protocol does not accept negative reported emissions — floor at zero and decide separately, per contract terms and reporting boundary, whether surplus instruments may be carried to another site or period.
Calorific Value: GCV vs NCV
Fuels are converted to energy via calorific value. Emission calculation always uses NCV (not user-selectable). The GCV/NCV choice affects only the reported energy figure (TJ) (default GCV), never the emission.
GWP Sets
To aggregate gases into CO2eq, each gas's emission is multiplied by its GWP. Four IPCC edition sets are in practical use — SAR/AR4/AR5/AR6 — and the same gas carries a different value in each, so the set used must be disclosed: an emission figure without its GWP set cannot be compared across years or companies. Some factors (e.g., IEA electricity factors) already embed GWP as CO2eq, so no additional GWP is applied (treated as GWP=1). See 제품 탄소발자국 (PCF) 산정 방법론 for the GWP characterization concept.
Emission Factors
Several factor types are used — per-gas factors (CO2·CH4·N2O), a single CO2eq factor (chiefly for electricity), calorific factors (GCV·NCV), and an oxidation factor — each distinguished as location-based or market-based. Factor sources, attributes, and assignment are covered in 배출계수 (Emission Factors); this document only describes how factors enter the formulas and states no specific factor value.
Unit Conversion & Energy Value
When units differ, values are converted to a common unit before multiplying (e.g., among L, kg, kWh, MWh, TJ). Energy use is produced in TJ and may be derived into toe/kcal for reporting (1 TJ ≈ 23.88 toe).
Organizational-Boundary Allocation
A per-source monthly allocation ratio (0–100%) can reflect the ownership/control share, scaling the source's emission before it rolls up to the site and corporation.
Worked Example
⚠️ The calorific and emission-factor numbers below are illustrative placeholders, not real factors. GWP uses characterization values (shown here as AR5 GWP100: CO2=1, CH4=28, N2O=265).
Stationary combustion — 1,000 L of diesel (illustrative values):
- Energy = 1,000 L × 0.035 GJ/L (illustrative NCV) = 35 GJ
- CO2 = 35 GJ × 74 kgCO2/GJ (illustrative) × 1 (oxidation factor) × 1 (GWP) = 2,590 kgCO2eq
- CH4 = 35 GJ × 0.003 kgCH4/GJ (illustrative) × 28 (GWP) ≈ 2.94 kgCO2eq
- N2O = 35 GJ × 0.0006 kgN2O/GJ (illustrative) × 265 (GWP) ≈ 5.57 kgCO2eq
- Total ≈ 2,598.5 kgCO2eq ≈ 2.60 tCO2eq
For electricity (location-based) there is no calorific or per-gas step — a single multiply: electricity use × grid-average CO2eq factor. The market-based result applies the contractual factor to the same usage and is presented alongside.
Basis & Standards
This methodology rests on the standards above (multiple bases per method); see the canonical list in GHG Protocol 및 Scope 분류 기준.
Standard-Alignment Notes
- Fugitive emissions not implemented — GHG Protocol Scope 1 includes fugitive emissions (refrigerants, SF6, etc.); the implementation covers only stationary/mobile/process — a completeness gap. Counter-proposal: add a fugitive/refrigerant category. Tracking issue proposed.
- Default GWP set = SAR — SAR (1995) matches Korea's K-ETS legacy but predates the current international recommendation (AR5/AR6). Counter-proposal: default AR5/AR6 for international reporting or require explicit set selection, with a national-regulation exception. Tracking issue proposed.