The GHG Protocol Corporate Standard defines three scopes for organisational GHG accounting:

• Scope 1 — direct emissions from sources owned or controlled by the reporting entity. Four canonical categories: stationary combustion (boilers, furnaces, kilns), mobile combustion (owned vehicles, ships, aircraft), process emissions (chemical and physical processes other than fuel combustion — cement clinker, ammonia, ethylene), and fugitive emissions (refrigerant leaks HFCs, SF6 from switchgear, methane from gas distribution).
• Scope 2 — indirect emissions from purchased energy. Covers purchased electricity, steam, heating, and cooling. Dual reporting mandatory under the GHG Protocol Scope 2 Guidance (2015) — location-based and market-based methodologies in parallel.
• Scope 3 — all other indirect emissions across the value chain. 15 categories — 8 upstream (purchased goods & services, capital goods, fuel- and energy-related activities, upstream transportation, waste, business travel, employee commuting, upstream leased assets) + 7 downstream (downstream transportation, processing of sold products, use of sold products, end-of-life, downstream leased assets, franchises, investments).

Boundary discipline requires the entity to elect an organisational boundary (equity share, operational control, or financial control) and apply it consistently across all operations. Most Thai listed issuers elect operational control. Base-year establishment fixes the reference point for target tracking with explicit recalculation policy for structural changes, methodology changes, and discovered errors.

The GHG Protocol Scope 2 Guidance (2015) mandates dual reporting — issuers disclose both methodologies in parallel:

• Location-based methodology — applies the regional grid average emission factor. In Thailand, this is the TGO-published grid emission factor updated annually based on the Thai national electricity mix. Reflects the average emissions intensity of the grid the entity draws from regardless of contractual procurement.
• Market-based methodology — applies emission factors from contractual instruments. Hierarchy: (1) supplier-specific factors from product/tariff disclosure, (2) Renewable Energy Certificates (REC) — Thai I-REC, international I-REC, EAC; (3) Power Purchase Agreements (PPA) with renewable-energy generators; (4) Guarantees of Origin (GO) for European purchases; (5) residual mix factor for unbundled grid procurement. Market-based reporting permits issuers to claim renewable-energy procurement benefits — typical for issuers with material PPA portfolios or RE100 commitments.

Bench handles the dual disclosure with explicit factor sourcing per methodology — TGO grid factor for location-based with prior-year and current-year disclosure; market-based with PPA contract terms, REC certificate identifiers, and supplier-specific tariff documentation. The two methodologies will diverge for any reporter with renewable-energy procurement, and that divergence is procurement-grade-significant — it represents the GHG benefit of the renewable procurement strategy.

The GHG Protocol Corporate Value Chain (Scope 3) Standard defines 15 categories. Not all categories apply to every reporter — most issuers report 6-12 material categories. Materiality screening determines which categories the entity reports — typically applied via:

• Size — relative emissions magnitude (estimated via spend-based or quick-screen calculation)
• Influence — entity influence over the value-chain emissions (high for own brand products, low for input commodities)
• Risk — financial or reputational exposure (high for litigation-prone categories)
• Stakeholders — stakeholder expectations (high for categories ratings analysts and NGOs focus on)
• Outsourcing — insourced vs outsourced activities (Scope 3 captures what is outsourced)
• Sector guidance — sector-specific Scope 3 materiality conventions

Categories deemed not material are explicitly disclosed and justified — non-disclosure without justification is a procurement-grade discipline failure. Data hierarchy for quantification: Primary data (direct measurement from value-chain partners — preferred), Secondary data (industry-average, sector-specific, environmentally-extended input-output / EEIO-based factors), Hybrid (primary for material categories, secondary for non-material). Methodology disclosure per category with data-quality assessment (PCAF-style 1-5 scoring increasingly common). Most Thai reporters start spend-based and progressively migrate to activity-based primary data over multiple reporting cycles.

The Thailand Greenhouse Gas Management Organisation (TGO) operates the Carbon Footprint for Organisation (CFO) programme as the senior Thai organisational GHG-accounting certification. Architecture:

• Methodology — aligned to ISO 14064-1 with Thailand-specific overlays. TGO publishes annual updates of the Thailand grid emission factor (currently around 0.4-0.5 kgCO2e/kWh, varying by year and methodology), Thai-specific fuel emission factors (natural gas, diesel, LPG, fuel oil with Thailand-specific calorific values and carbon contents), and sector-specific guidance for high-emitting sectors.
• Certification cycle — (1) entity prepares organisational GHG inventory; (2) submits data packet to TGO; (3) TGO assigns or entity selects a TGO-accredited verification body (typically DNV, Bureau Veritas, SGS, LRQA, TÜV, or Thai-equivalent firms with TGO accreditation); (4) verifier performs documentation review, sample-site review, calculation re-performance, management interview; (5) verifier issues verification statement; (6) TGO reviews and issues TGO CFO certificate. Cycle typically 3-6 months from data submission to certificate issuance.
• Recognition — certificate carries domestic recognition with Thai SEC, SET ESG Ratings, Thai institutional investor IR, government-linked investment funds, and Thai-pension-fund allocation criteria. Particular weight for Thai-domiciled issuers seeking domestic capital allocation.

TGO CFO is the entry-level certification for any Thai listed or Thai-domiciled issuer pursuing GHG-disclosure discipline; for international-investor-facing issuers it is layered with ISAE 3410 limited or reasonable assurance.

PCAF (Partnership for Carbon Accounting Financials) provides the senior global methodology for financed-emissions calculation under Scope 3 Category 15 (Investments). For Thai banks, insurers, and asset managers, PCAF is the operative methodology for NZBA, NZIA, and SBTi-Financial Services pathway alignment.

Six core asset classes with distinct calculation methodology:

• Listed equity and corporate bonds — attribution via outstanding investment / enterprise value including cash (EVIC); counterparty Scope 1+2 emissions; data-quality 1-5 scoring.
• Business loans and unlisted equity — attribution via outstanding loan or equity / total equity + debt; counterparty emissions.
• Project finance — attribution via outstanding investment / total project equity + debt; project Scope 1+2 emissions.
• Commercial real estate — attribution via outstanding loan / property value; building energy consumption.
• Mortgages — attribution via outstanding loan / property value; residential building energy consumption.

Plus two additional asset classes: motor vehicle loans (attribution via outstanding loan / vehicle value, vehicle emissions) and sovereign debt (attribution via investment / sovereign GDP, sovereign emissions).

Data quality scoring 1-5: Score 1 = verified emissions disclosed by counterparty (best); Score 2 = unverified emissions disclosed; Score 3 = economic activity-based proxies from primary data; Score 4 = sector-average; Score 5 = revenue or asset-based estimation (lowest). PCAF requires disclosure of data-quality distribution across the portfolio. Bench operates PCAF documentation bilingual with terminology lock to BOT 2023 FI climate Policy Statement and NZBA / NZIA / SBTi-FS commitments.

GHG inventory verification operates two layered standards:

• ISO 14064-3 — the verifier-side international standard for GHG statement validation and verification. Establishes principles, process, materiality, sampling, agreement, opinion, and reporting requirements for verification bodies. TGO-accredited verifiers operate under ISO 14064-3 with TGO-specific overlays for the CFO certificate.
• ISAE 3410 — Assurance Engagements on Greenhouse Gas Statements — the assurance-firm standard issued by the IAASB. Applies when an assurance firm (typically an audit firm) provides an independent opinion on a GHG statement. Two assurance levels:

Limited assurance — negative-form conclusion (“nothing has come to our attention that causes us to believe the GHG statement is not, in all material respects, fairly stated”). Lower-level procedures — primarily inquiry and analytical review with limited substantive testing. Lower cost. Most common for first-year and small-issuer GHG assurance.

Reasonable assurance — positive-form conclusion (“in our opinion, the GHG statement is fairly stated, in all material respects”). Higher-level procedures — substantive testing, recalculation, sample-site visits, third-party confirmations. Higher cost. Increasingly the expectation for SET-50 and FI issuers; required where regulators or investors mandate.

Thai SAE (Standards on Assurance Engagements) under FAP (Federation of Accounting Professions) provides the Thai-language assurance pathway. Most mature Thai reporters operate a layered architecture — TGO CFO verification (under TGO + ISO 14064-3) plus ISAE 3410 limited (from a separate assurance firm) for international investor recognition.

The Science Based Targets initiative (SBTi) is the senior global body validating corporate GHG reduction targets against climate science. Architecture:

• Near-term targets — typically 5-10 years horizon (2030-typical for current submitters). 1.5°C-aligned reduction ambition under the latest methodology. For cross-sector calculation, typical Scope 1+2 near-term reduction is 42% absolute by 2030 from a recent base-year (with annual reduction rate ~4.2%). Sector-specific decarbonisation pathways apply for energy, industrials, FIs (SBTi-FS with sector-specific portfolio coverage), real estate, transport. Scope 3 near-term mandatory where Scope 3 >40% of total emissions.
• Long-term targets under the SBTi Corporate Net-Zero Standard — typically 2050 or earlier (sector-pathway-dependent). Requires 90%+ absolute value-chain abatement before residual offsets — meaning the net-zero claim must rest primarily on actual emissions reduction rather than offset purchase.
• Validation cycle — (1) commitment letter (public statement of intent); (2) 24-month window for target submission; (3) SBTi technical validation (typically 3-6 months); (4) target listing publicly; (5) annual public progress reporting.

For Thai issuers, SBTi target validation increasingly is the disclosure expectation across CDP Climate Change Leadership band, S&P Global CSA, MSCI Environmental pillar, and SET ESG Ratings. Bench operates SBTi commitment letter, target submission documentation, validation back-and-forth coordination, and annual progress narrative with terminology lock to the master inventory.

The base-year is the historic reference point against which target progress is tracked. Under the GHG Protocol Corporate Standard, every reporter establishes a base-year (typically a recent historical year with stable operations and good data quality) and discloses it explicitly with a recalculation policy.

Recalculation triggers under the GHG Protocol:

• Structural changes — acquisitions, divestments, mergers, outsourcing or insourcing of operations. Recalculation back-applies the new boundary to the base-year for like-for-like comparison.
• Methodology changes — adoption of new emission factors (e.g. TGO updates Thailand grid factor methodology), new GWP values (IPCC AR5 → AR6 transition), new calculation approach (spend-based → activity-based primary data for a material category).
• Discovered errors — material data errors identified after the original disclosure, requiring restatement.
• Significance threshold — recalculation typically applied where the impact exceeds a disclosed significance threshold (typically 5% of total or 5% of scope-level emissions).

Recalculation policy is disclosed and applied consistently. Bench operates a methodology log and a recalculation log carried in the working file year-on-year — every methodology change, every restated figure, every IPCC GWP update tracked with explicit lineage. Continuity preservation is procurement-grade — TGO CFO certificate, ISAE 3410 assurance, CDP submission, and SBTi annual progress all depend on a coherent base-year reference and disclosed recalculation history.

One organisational GHG inventory feeds seven downstream deliverables — and procurement-grade discipline requires zero drift across them:

• IFRS S2 cross-industry metric 1 — Scope 1, Scope 2 (location and market-based), Scope 3 GHG with methodology disclosure, base-year, and recalculation log.
• 56-1 One Report climate chapter — SEC-filed authoritative emissions disclosure with Thai SEC sustainability-disclosure compatibility.
• Sustainability report emissions section — GRI 305-aligned disclosure, multi-year trend data, intensity metrics.
• Standalone climate report — metrics-and-targets pillar with full emissions breakdown by source and category.
• CDP Climate Change C5-C7 — emissions methodology (C5), emissions data (C6 with Scope 1/2/3 breakdown by GHG and by category), energy (C7).
• SBTi target submission and annual progress — baseline emissions, progress against near-term and long-term targets.
• Ratings climate dimensions — S&P Global CSA emissions questions, MSCI Environmental pillar, Sustainalytics Carbon Risk Rating, FTSE Russell Climate theme, Bloomberg Carbon Intensity Score, SET ESG environmental dimension.

Every emissions figure must reconcile across all seven — same boundary, same methodology, same emission factors, same GWPs, same prior-year comparative, same base-year. Drift between deliverables signals to ratings analysts and assurance firms that the underlying inventory is incoherent — procurement-grade defect. Bench architecture carries the inventory in a master working file with documentation lineage from each emission figure to each downstream deliverable, with a quarterly reconciliation pass during peak disclosure cycles.

Three verification routes operate in parallel:

• (1) Standards-body verification — ISO 17100 (translation services quality) and ISO 27001 (information security management). Both are independently auditable and procurement-team-verifiable through certificate disclosure.
• (2) Structured procurement reference disclosure — under mutual NDA, scoped to seven GHG-inventory document categories, GHG Protocol Corporate Standard + Scope 3 Standard methodology fluency, ISO 14064-1/-2/-3 alignment, TGO CFO submission and TGO-accredited verifier engagement history, TGO CFP product certification track record, T-VER project documentation, PCAF financed-emissions architecture for FIs, SBTi commitment-and-validation track record, ISAE 3410 limited and reasonable assurance dossier preparation, Thai SAE FAP-pathway compatibility, IPCC AR6 GWP transition handling, base-year and recalculation log discipline, cross-deliverable IFRS S2 / CDP / 56-1 / SBTi / ratings reconciliation.
• (3) Pre-engagement scoping call — 30-minute call within 2 business days of mutual NDA, covering framework alignment (GHG Protocol + ISO 14064 + TGO + sector-specific), boundary discipline (organisational and operational), Scope 3 materiality screening approach, verifier engagement architecture, and multi-deliverable orchestration.

For annual GHG-inventory panel placement, the bench supplies a 10-component capability brief within 3-5 business days of structured RFP — covering bench composition, GHG Protocol + ISO 14064 methodology, TGO CFO submission handling, Scope 3 architecture, PCAF for FIs (where applicable), SBTi commitment-and-progress, ISAE 3410 layered assurance preparation, 56-1 One Report integration, multi-deliverable IFRS S2 / CDP / ratings feeding, sector experience, conflicts and confidentiality, and framework rate card.