Foreword from the Expert Team:
Since Decision 13/2024/QD-TTg was issued in August 2024, our consulting team – Carbon Credit Viet Nam Joint Stock Company – has received hundreds of calls from enterprises asking about their greenhouse gas inventory obligations. The most common question is: “What are Scope 1, 2 and 3? What do we have to measure, and how do we calculate it?”
This article has been compiled based on our practical experience, combined with official guidance documents from the GHG Protocol, the IPCC and the Ministry of Natural Resources and Environment (MONRE). Our goal is to help your enterprise clearly understand the nature of the 3 emission Scopes, the calculation methods, and the specific implementation steps required to meet legal requirements.
1. Overview: The GHG Protocol and Vietnam’s Legal Framework
1.1. The GHG Protocol – The global standard
- Corporate Accounting and Reporting Standard (2004) – Core requirements for organizational GHG inventories
- Scope 2 Guidance (2015) – Dual reporting: location-based and market-based methods
- Corporate Value Chain (Scope 3) Standard (2011) – Defines 15 categories of indirect value chain emissions
The GHG Protocol (Greenhouse Gas Protocol) was developed from 1998 by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD). The Greenhouse Gas Inventory Methodology provides a systematic framework for identifying, calculating, and reporting corporate GHG emissions. It is the most widely used framework in the world for corporate greenhouse gas inventories, used by 92% of Fortune 500 companies reporting to CDP (Deloitte, 2024; GHG Protocol, 2004).
The principal standards within the GHG Protocol system:
1.2. Vietnam’s legal framework
Decree 06/2022/ND-CP (07/01/2022) establishes the legal framework for GHG emission reduction. Decision 13/2024/QD-TTg (13/08/2024) updates the list of facilities required to conduct GHG inventories, expanding from 1,907 to 2,166 facilities across 6 sectors (Government of Vietnam, 2022; 2024).
| Sector | Number of facilities | Applicable threshold |
|---|---|---|
Industry and Trade (thermal power, steel, cement, chemicals…) | ~1.787 | ≥3,000 tCO2e/year |
Construction (commercial buildings) | 229 | ≥1.000 TOE/ year |
Transport | 75 | ≥1.000 TOE/ year |
Natural Resources and Environment (waste treatment) | ~75 | ≥65,000 tonnes/year |
TOTAL | 2.166 | – |
Source: Decision 13/2024/QD-TTg
2. The Seven Greenhouse Gases and Global Warming Potential (GWP)
The GHG Protocol stipulates 7 greenhouse gases that must be inventoried. Global Warming Potential (GWP) is the factor for converting to CO₂ equivalent over a 100-year time horizon (GHG Protocol, 2024; IPCC, 2021).
Conversion formula:
CO₂e = Mass of gas × GWP. Example: 1 tonne of leaked SF₆ = 24,300 tonnes of CO₂e.
| Greenhouse gas | Công thức | GWP 100 năm | Main emission sources |
|---|---|---|---|
| Carbon dioxide | CO₂ | 1 | Fuel combustion, industrial production |
Methane (fossil) | CH₄ | 29,8 | Oil and gas, coal mining |
| Nitrous oxide | N₂O | 273 | Agriculture, chemicals |
| Sulfur hexafluoride | SF₆ | 24.300 | High voltage electrical equipment |
HFC-134a (refrigerant) | C₂H₂F₄ | 1.530 | Air conditioners, refrigerators |
Source: IPCC AR6 (2021); GHG Protocol GWP Values (2024)
3. Scope 1: Direct emissions
Scope 1 covers all GHG emissions from sources owned or directly controlled by the enterprise. This scope is mandatory for reporting under Vietnamese regulations (GHG Protocol, 2004; Persefoni, 2024).
3.1. The four types of Scope 1 emission sources
| Source type | Specific examples | Data to be collected |
|---|---|---|
Stationary combustion | Boilers, kilns, diesel generators | Fuel consumption (litres, m³, kg) |
Mobile combustion | Company trucks, passenger cars, forklifts | Petrol/diesel consumption per vehicle |
Process emissions | Cement, steel, chemical production | Product output, input raw materials |
Fugitive emissions | Refrigerants (R-410A, R-134a), SF₆ | Top-up purchases, opening/closing inventory |
3.2. Scope 1 calculation formula
The Greenhouse Gas Inventory Methodology applies activity data and appropriate emission factors to calculate emissions from identified sources. Basic formula: Emissions = Fuel quantity × Emission factor
4. Scope 2: Indirect emissions from purchased energy
Scope 2 covers emissions from electricity, steam, heating and cooling purchased and used by the enterprise. The emissions occur at the power plant but are “attributed” to the consuming enterprise (GHG Protocol, 2015).
4.1. Hai phương pháp tính: Location-based và Market-based
The GHG Protocol Scope 2 Guidance (2015) requires dual reporting when contractual instruments such as I-REC renewable energy certificates are involved (Ecohz, 2024; Persefoni, 2024b).
| Criterion | Location-based | Market-based |
|---|---|---|
Definition | Average emission factor of the regional power grid | Factor from the specific electricity source under contract |
Applicable instruments | National/regional grid emission factor | I-REC, PPA, hệ số nhà cung cấp |
Significance | Reflects the actual impact on the power grid | Reflects the enterprise’s energy purchasing choices |
4.2. Vietnam’s grid emission factor
Vietnam’s grid emission factor for 2023 is 0.6592 tCO₂/MWh (Official Letter 1726/BDKH-PTCBT). This figure has fallen from 0.9130 tCO₂/MWh in 2018 thanks to renewable energy (Climate Change Vietnam, 2024).
Example:
A plant consumes 5,000 MWh/year → Scope 2 = 5,000 × 0.6592 = 3,296 tonnes of CO₂e (location-based).
5. Scope 3: Value chain emissions
Scope 3 covers other indirect emissions across the value chain. According to CDP, supply chain emissions are on average 26 times greater than operational emissions (GHG Protocol, 2011; Plan A, 2024).
Upstream – 8 categories:
| Cat | Category name | Description |
|---|---|---|
| 1 | Purchased goods and services | Machinery, equipment, buildings, IT infrastructure |
| 2 | Capital goods | Machinery, equipment, buildings, IT infrastructure |
| 3 | Fuel- and energy-related activities | Well-to-tank, transmission losses |
| 4-5 | Upstream transportation / Waste | Inbound transport, third-party waste treatment |
| 6-7 | Business travel / Employee commuting | Flights, business vehicles, daily commuting |
| 8 | Upstream leased assets | Leased equipment and buildings |
Downstream – 7 categories:
| Cat | Category name | Description |
|---|---|---|
| 9-10 | Downstream transportation / Processing of sold products | Delivery to customers, further processing by third parties |
| 11 | Use of sold products | Emissions from customer use of products (important for automobiles) |
| 12-14 | End-of-life / Leased assets / Franchises | Product disposal, leased-out assets, franchising |
| 15 | Investments | Financed emissions (important for banks) |
6. Compliance roadmap in Vietnam
7. Conclusion
A greenhouse gas inventory across the 3 Scopes (Scope 1, 2, 3) is the foundation for all carbon management activities – from legal compliance and ESG reporting to setting science-based targets (SBTi) and participating in the carbon market. A consistent Greenhouse Gas Inventory Methodology helps enterprises build reliable emissions data for management, reporting, and future reduction planning.
With the 31/03/2025 deadline approaching, enterprises subject to mandatory requirements need to:
- Define their organizational boundary and emission sources
- Apply emission factors from MONRE Decision 2626
- Lập báo cáo theo Mẫu 06 và nộp đúng hạn
A message from the ESG Expert Team – Carbon Credit Viet Nam Joint Stock Company
Throughout our work supporting enterprises with GHG inventories, we have found that the biggest challenge is not the calculation formulas but data collection. Many enterprises do not have a systematic process for tracking fuel and electricity consumption.
Our advice: Start with Scope 1 and Scope 2 – these are mandatory under Vietnamese regulations and are also the areas over which the enterprise has direct control. Scope 3 can be rolled out gradually once a solid foundation is in place.
If your enterprise needs support with GHG inventories – from boundary setting, data collection and emissions calculation to preparing reports in the prescribed format – our team of experts is ready to accompany you.
Respectfully,
ESG Expert Team – Carbon Credit Viet Nam Joint Stock Company
Reference List
Government of Vietnam (2022) Decree No. 06/2022/ND-CP on mitigation of greenhouse gas emissions and protection of the ozone layer. Hanoi: The Government.
Government of Vietnam (2024) Decision No. 13/2024/QD-TTg promulgating the list of greenhouse gas-emitting facilities required to conduct inventories. Hanoi: The Prime Minister.
Climate Change Vietnam (2024) ‘Vietnam’s 2023 Updated Grid Emission Factor’, International Climate Initiative (IKI). Available at: https://www.climatechange.vn/ (Accessed: February 2025).
Deloitte (2024) ‘Development of the GHG Protocol’, DART – Deloitte Accounting Research Tool. Available at: https://dart.deloitte.com/
Ecohz (2024) ‘GHG Protocol Scope 2 Guidance’, Ecohz Standards. Available at: https://www.ecohz.com/
GHG Protocol (2004) A Corporate Accounting and Reporting Standard. Revised Edition. Washington, DC: WRI and WBCSD.
GHG Protocol (2011) Corporate Value Chain (Scope 3) Accounting and Reporting Standard. Washington, DC: WRI and WBCSD.
GHG Protocol (2015) GHG Protocol Scope 2 Guidance. Washington, DC: WRI and WBCSD.
GHG Protocol (2024) Global Warming Potential Values. August 2024 Update. Available at: https://ghgprotocol.org/
IPCC (2021) Climate Change 2021: The Physical Science Basis. AR6 Working Group I. Cambridge: Cambridge University Press.
MONRE (2022) Decision No. 2626/QD-BTNMT on the list of emission factors for GHG inventories. Hanoi: Ministry of Natural Resources and Environment.
Persefoni (2024) ‘Scope 1 Emissions: An Explainer Guide’, Persefoni Blog. Available at: https://www.persefoni.com/
Plan A (2024) ‘What are Scopes 1, 2 and 3 of Carbon Emissions?’, Plan A Academy. Available at: https://plana.earth/
US EPA (2024) GHG Emission Factors Hub. Washington, DC: US EPA. Available at: https://www.epa.gov/
Disclaimer:
This article has been prepared for the purpose of providing general guidance information and does not constitute professional advice. Legal regulations may be updated. Enterprises should consult experts before implementation.
© 2025 Carbon Credit Viet Nam Joint Stock Company. All rights reserved.