The Covenant of Mayors for Climate and Energy – Europe (CoM EU) is the largest European initiative for local climate and energy action, bringing together around 12,000 local authorities. Its aim is to support the design and implementation of effective climate policies at the city level. Signatories to the pact voluntarily commit to developing and implementing Sustainable Energy and Climate Plan (SECAP), a key part of which is the compilation of greenhouse gas (GHG) emissions inventories. This document, published by the Joint Research Centre (JRC) of the European Commission, provides detailed guidance on how to prepare such an inventory within the CoM framework.

Importance and objectives of GHG emission inventory

Greenhouse gas emission inventories are essential for informed planning, implementation and monitoring of effective climate change mitigation measures at the local level. They provide detailed information on municipal activities, such as final energy consumption and waste generation, and their associated GHG emissions for the reference year. They help municipalities plan, monitor and measure the impacts of their SECAP and adapt it over time. Transparent planning and communication of results increases credibility and engagement of all stakeholders.

CoM Emission Inventory Framework

The CoM framework is guided by the guiding principles of data quality, consistency, transparency and comparability, while ensuring flexibility to meet local and regional needs. The emphasis is on the ‘energy first’ principle, which prioritises reducing energy demand, in line with the Energy Efficiency Directive. The CoM targets for GHG emission reductions are in line with the EU’s commitments, namely 55 % emission reduction by 2030 and climate neutrality by 2050.

Key concepts:

• Emission inventory: It quantifies the annual GHG emissions associated with the local territory for the reference year by activity sectors.
• Data activities: They quantify human activities in a local area (e.g. energy consumption in MWh, amount of waste in tons).
• Emission factor (EF): It expresses GHG emissions per unit of activity (e.g. GHG emissions per MWh of energy consumed).
• Baseline Year: The year to which the emissions reduction target is compared. Must be from 1990 or later, with 2005 and 2010 commonly used.
• Baseline Emission Inventory (BEI): It quantifies GHG emissions for the base year and is the starting point for SECAP.
• Monitoring Emission Inventory (MEI): It is compiled regularly to monitor progress towards emission reduction targets.

Scope, boundaries and sectors of activities

CoM inventories use territorial approach, which means that emissions from activities occurring within the geographical boundaries of the municipality are recorded. They include direct emissions (Scope 1) from local energy consumption and non-energy activities (e.g. fuel combustion) and indirect emissions (Scope 2) related to local consumption of energy supplied from the grid (electricity, heating, cooling).

Key sectors of activities to be included:

• Municipal buildings, facilities and equipment
• Tertiary (non-general) buildings, facilities and equipment
• Residential buildings
• transportation It is also recommended to include waste management and wastewater treatmentSectors and activities covered by the EU ETS (e.g. large industry, except in specific cases) should be excluded, while those recently added to ETS2 (buildings, road transport, municipal waste incineration) will remain included.

Methodological choices

When calculating GHG emissions, data activities are multiplied by emission factors. Municipalities can choose from two approaches:

• Activity-based approach: It focuses on GHG emissions that arise from energy conversion (e.g. fuel combustion).
• Life cycle approach (LC-based approach): It extends the scope to include GHG emissions associated with the energy supply chain.

Greenhouse gases: It is recommended to include three reference GHGs: CO2, CH4 and N2O, which are then converted into carbon dioxide equivalents (CO2-eq) using IPCC global warming potential (GWP) values.

Emission factors (EF): Local governments can either use default EFs (e.g. provided by the JRC) or develop their own, context-specific EFs, as long as they are reliable and transparently documented.

Data collection and documentation

Data collection is an integral part of the preparation of a GHG inventory. Data on final energy consumption are typically expressed in megawatt hours (MWh) and disaggregated by sector of activity and energy source/carrier (e.g. electricity, fossil fuels, biofuels, heating/cooling). For non-energy sectors such as waste management, units of mass or volume (e.g. tonnes of waste) are used. Data can be obtained from national/regional statistics, from market operators or through surveys.

All collected data, calculations and assumptions must be documented in detail in SECAP, to ensure transparency and consistency. This documentation should include information on the geographical boundaries, base and reference year, emission reduction target, population, chosen approach, GHGs covered, units, activity sectors, local energy production and emission factors used.

Preparing a thorough greenhouse gas inventory within the CoM is key to effective climate governance at the local level. It provides a basis for strategic planning, progress monitoring and transparent communication, supporting municipalities in their pursuit of a sustainable energy transition and achieving climate neutrality goals. JRi