Emissions inventory and a comparable baseline

An inventory answers a specific question: which emissions are attributed to an organization during a stated period and within declared boundaries? A project-impact estimate asks what happened compared with what would have happened without the intervention. A falling inventory line therefore does not establish the climate impact of a project. Under the GHG Protocol Corporate Standard, an organization selects an appropriate consolidation approach, such as equity share, financial control or operational control, and applies it consistently. Direct emissions fall within scope 1, relevant purchased-energy emissions within scope 2, and other value-chain emissions within scope 3. This accounting map helps assign responsibility; it does not by itself determine where capital should go. An important opportunity may sit with a supplier outside direct operating authority.

Before calculating, create a boundary table linking facility, contract, emissions source, consolidation approach and data responsibility. A minority holding in a joint venture does not automatically mean that the same ownership percentage applies when the organization's chosen approach is operational control. Examine authority to introduce and implement operating policies. Once boundaries are established, calculate each flow using activity data and a suitable factor with consistent units. Megawatt hours multiplied by tonnes of carbon dioxide equivalent per megawatt hour gives tonnes. Divide by one thousand if the factor is expressed in kilograms. Record the factor's year, coverage and source. Do not mix a direct combustion factor with a lifecycle factor containing upstream emissions and then add both to the same flow.

Test sensitivity to the quality of the steam factor before recommending the proposal. If the actual factor is 0.26 rather than 0.23, steam emissions become 22,100 tonnes and the total becomes 42,100: an increase of 2,100 tonnes, or 5.25%. The break-even factor within these boundaries is 20,000 ÷ 85,000, approximately 0.2353 tonnes per delivered megawatt hour of steam. Request an explanation of whether the factor applies at generation or delivery and how network losses and fuel allocation in combined heat and power were handled. Do not choose an allocation method because it produces the lowest number. Compare permitted, declared methods consistently and disclose sensitivity. When missing evidence could move an alternative across the break-even threshold, the recommendation remains conditional on obtaining that evidence.

For electricity, the 2015 Scope 2 Guidance distinguishes an approach using the average grid in the consumption location from an approach using qualifying contractual instruments. Where dual reporting applies, identify both results by their method. A contractual certificate alone does not demonstrate that a factory's consumption hours matched a particular generator or that the network gained additional firm capacity. In the investment memorandum, distinguish the contractual inventory outcome, the operational change and any estimate of avoided emissions beyond the inventory. The latter requires an explicit counterfactual. Keep offsets separately identified rather than subtracting a credit in a way that hides an ongoing activity source. Apply the relevant framework's accounting and disclosure requirements to each component. The GHG Protocol update dated 16 October 2026 describes proposed revisions still under development; proposals should not be treated as issued final requirements.

Choose the baseline to suit the question. For accounting comparisons over time, retain a base year and a policy for recalculating it when relevant changes occur. For an efficiency assessment under changing production, construct an activity-adjusted comparison. Purchasing steam instead of producing it does not justify removing the corresponding emissions from the comparison. The Corporate Standard explains that the base-year recalculation consequences of outsourcing depend on the scopes being tracked. Neither every operational change nor every acquisition should be treated as an efficiency improvement. Preserve a column for the published value, another for the adjusted comparison, and a reason for their difference. Readers can then distinguish reclassification from reduced consumption or a changing grid factor without losing the historical record.

Use a simple decomposition to understand change: activity multiplied by energy per unit of activity, then by the emissions factor. State the order in which you replace these terms when isolating their contributions. Different orders can allocate the interaction effect differently while leaving the total change unchanged. If production rises 20%, energy intensity falls 10% and the factor stays constant, relative consumption becomes 1.20 × 0.90 = 1.08. Energy and emissions rise 8%. Better intensity does not ensure a lower total. Report both where they affect the decision. This decomposition does not prove that a particular project caused the improvement: product mix, weather and operating hours can also change and need investigation.

Prioritize data improvement around decisions that could reverse. If a major investment depends on a small difference between poorly documented factors, examining the factors matters more than displaying extra decimal places. Reconcile site consumption with invoices before allocating it to equipment through submeters or declared estimates. An unexplained residual is a reason to investigate, not an earned saving. Set a review threshold appropriate to the case's materiality and identify who can revise a factor and approve its version. Preserve the original input and the correction history so an unrecorded adjustment does not create conflicting finance and sustainability reports. These controls make data usable for comparison and monitoring while retaining its real uncertainty.