ISO 14064-1: GHG Inventory and Evidence

Objective and users

Before calculating anything, it is worth defining what the inventory will be used for: internal management, a client, a tender, a regulatory requirement, financing, a reduction target or a verification. The purpose determines materiality, frequency, the level of evidence required and the claims that can be made from the result.

It is also worth identifying the intended users of the report and the criteria that will be applied. A corporate inventory should not be mixed up with a product or project footprint: these are different exercises, with different boundaries and methodologies.

Principles

Inventory information must be:

• relevant;
• complete;
• consistent;
• accurate;
• transparent.

Exclusions are always justified. Accuracy does not mean an absence of uncertainty, but the use of methods and data appropriate to the intended use of the inventory.

Organisational boundaries

It is determined which entities and operations are consolidated within the inventory. The usual methods are:

• operational control;
• financial control;
• equity share.

The choice must be applied consistently and must explain how subsidiaries, facilities, leases, temporary joint ventures (UTEs) and any changes that occur are treated. The method is not chosen in order to exclude inconvenient emissions.

Reporting boundaries

ISO 14064-1 classifies direct and indirect emissions by category. Many organisations also use, in parallel, the Scope 1, 2 and 3 language of the GHG Protocol. When both frameworks are used, it is worth maintaining a mapping table between categories and clearly stating the methodology followed.

The most common emission sources are:

• stationary combustion;
• vehicles;
• refrigerant leaks;
• processes;
• purchased electricity, heat or cooling;
• transport and travel;
• purchases and capital goods;
• waste;
• use and end-of-life of products.

Significant indirect emissions are selected using documented criteria — magnitude, influence, risk, expectations and data availability — avoiding the exclusion of a category simply because it is difficult to calculate.

Source and owner map

Each data point also needs a unit, period, site, source, transformation applied and quality control.

Data collection

Priority is always given to measured primary data. When some consumption has to be estimated, the method, the assumption used and its effect on the result are recorded. Units are standardised and double counting is avoided.

Standard controls include:

• reconciliation with invoices and meters;
• year-on-year comparison;
• outlier detection;
• coverage of all twelve months of the period;
• review of new or closed sites;
• approval by the data owner;
• locking of the final version.

Emission factors

Each emission factor used must document:

• issuing body and source document;
• version and year;
• geographic scope;
• gas included;
• unit and calorific value;
• global warming potential applied;
• approach used for electricity;
• download date.

Factors from different years or countries are not mixed without justification. If the issuing body updates a table of factors, the version used is tracked and documented.

Calculation and traceability

The basic calculation formula is as follows:

Emissions = activity data × emission factor × applicable conversions

Every result must be traceable back to its source evidence. The calculation spreadsheet or tool is protected against unauthorised changes, retains its formulas and records the revisions made.

Gases and tonnes of CO₂ equivalent are reported in line with the chosen methodology. Removals and offsets must not be confused with the inventory’s gross emissions.

Electricity: approaches and contracts

When location-based or market-based approaches are used for electricity, the criteria and sources applied must be stated. Guarantees of origin and contracts are reviewed to avoid double counting and overstated claims.

Purchasing renewable electricity does not automatically make the whole organisation “zero emissions”. The report must clearly separate the inventory result, the contractual instruments used and any offsets.

Refrigerants

Refrigerant leaks can be a material source of emissions. Equipment, gas type, charge, refills carried out and equipment decommissioning are all inventoried. Maintenance records are the key evidence for this calculation.

It should not be calculated from purchases alone if there are transfers or refrigerant stock. The mass balance must be documented.

Significant indirect emissions

For the value chain, an initial screening can be applied using spend data or secondary sources, and priority categories can then be refined with physical data or supplier information.

Criteria for prioritising categories include:

• likely magnitude;
• reduction potential;
• relevance to customers;
• risk;
• quality of available data;
• the organisation’s influence.

When a category is excluded, that decision is explained and reviewed periodically.

Base year and recalculation

The base year allows performance to be compared over time. It must be representative and have reliable data available. The recalculation policy defines the threshold and the events that trigger it:

• acquisitions and divestments;
• changes in organisational boundaries;
• material errors;
• methodological change;
• significant new information.

Organic growth is treated according to what the policy establishes. The base year is not changed to artificially improve the trend.

Uncertainty and quality

Uncertainty comes from measurement, from estimation and from the emission factors themselves. It is assessed qualitatively or quantitatively depending on the inventory’s needs.

A quality matrix can score data according to these dimensions:

The improvement plan prioritises sources that are both material and low quality.

GHG report

The report must explain:

• organisation and person responsible;
• purpose and period;
• boundaries and method;
• gases and categories;
• results by category;
• exclusions;
• factors and global warming potentials applied;
• uncertainty;
• base year and recalculation;
• methodological changes;
• measures adopted and verification statement.

Transparency also includes the inventory’s limitations. Charts should not be published on their own, without the methodology behind them.

Verification

Independent verification increases confidence in the inventory, but it requires preparation. The level of assurance, materiality, scope and criteria are defined together with the verification body.

The organisation prepares a file for each data point, factor, calculation and decision made. The verifier must be able to reproduce the result from a sample.

Verification is not equivalent to a neutrality certification and does not validate future reduction targets.

12-week plan

Weeks 1-2

Purpose, team, boundaries and methodology.

Weeks 3-5

Source map, data collection and emission factors.

Weeks 6-7

Calculation, controls and reconciliation.

Weeks 8-9

Indirect emissions, uncertainty and base year.

Week 10

Report and internal review.

Weeks 11-12

Corrections and verification preparation.

Common mistakes

1. Not defining the purpose of the inventory.
2. Confusing organisational boundaries with operational ones.
3. Excluding indirect emissions for lack of data.
4. Using emission factors without version control.
5. Double-counting electricity.
6. Ignoring refrigerant emissions.
7. Mixing up emissions and offsets.
8. Not recalculating the base year when required.
9. Lacking documentary evidence.
10. Claiming neutrality just because the inventory has been verified.

Checklist

• Purpose and users defined.
• Organisational boundaries justified.
• Categories and significance established.
• Data map and owners assigned.
• Evidence and reconciliations complete.
• Emission factors version-controlled.
• Calculations reproducible.
• Base year and recalculation policy defined.
• Uncertainty assessed and improvement plan in place.
• Transparent report.
• Verification correctly stated.

Frequently asked questions

Is ISO 14064-1 certifiable?

What is usually discussed is verification of the inventory against a set of criteria, not certification of a management system.

Does it require calculating full Scope 3?

It requires identifying and selecting significant indirect emissions using documented criteria; the approach must be stated and kept consistent over time.

Does a verified footprint mean neutrality?

No. Verifying the quantification does not demonstrate neutrality or an actual reduction in emissions.

Which version is currently in force?

ISO 14064-1:2018, reviewed and confirmed by ISO in 2024.

Sources consulted

• ISO 14064-1:2018, official record.
• ISO Online Browsing Platform.
• GHG Protocol Corporate Standard.
• GHG Protocol Scope 2 Guidance.
• GHG Protocol Scope 3 Standard.

The Summum Calidad team can support the preparation of the inventory, evidence control and verification readiness, as well as its integration within an ISO 14001 environmental management system or a broader ESG reporting framework.