Greenhouse Gas Inventory

A greenhouse gas (GHG) inventory is a list of emission sources and the associated emissions quantified using standardised methods. Organisations develop GHG inventories for a variety of reasons, including:

  • Managing GHG risks and identifying reduction opportunities
  • Participating in voluntary or mandatory GHG programs
  • Participating in GHG markets
  • Achieving recognition for early voluntary action

The GHG inventory development process consists of four key steps:

  1. Start by reviewing accounting standards and methods (see for example the GHG Protocol, determining organisational and operational boundaries, and choosing a base year.
  2. Collect data and quantify GHG emissions (Scope 1, 2 and 3 emissions).
  3. Develop a GHG Inventory Management Plan to formalise data collection procedures.
  4. Set a GHG emission reduction target and track and report progress.

What are Scope 1, 2 and 3 Emissions?

Scope 1 emissions are direct GHG emissions that occur from sources that are controlled or owned by an organisation (e.g., emissions associated with fuel combustion in boilers, furnaces, vehicles).

Scope 2 emissions are indirect GHG emissions associated with the purchase of electricity, steam, heat, or cooling.

Scope 3 emissions are the result of activities from assets not owned or controlled by the reporting organisation, but that the organisation indirectly impacts in its value chain. Scope 3 emissions include all sources not within an organisation’s scope 1 and 2 boundary.

How do you Calculate GHG Emissions?

Greenhouse gas (GHG) emissions are quantified using either direct measurement or calculation methods. The selection of a quantification method will depend on the information that is available for each source. A key component of developing a GHG inventory requires the use of emission factors. An emission factor presents the quantity of a GHG emitted to the atmosphere associated with a specific activity.

Our consultants at WKC specialise in inventory preparation using internationally recognised standards and protocols, through the use of measured data (emissions monitoring data), stoichiometry (for bespoke fuel usage) and emission factors for sources where detailed data is not available.

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