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The popular saying that ‘you can’t manage what you don’t measure’ is particularly appropriate for overseeing energy consumption and GHGs   emissions in an organisation. Accurate, trusted and transparent data is the fundamental basis for effective energy and carbon management. An organisation can only make smart decisions about energy procurement, improve efficiency of buildings, processes and equipment, detect avoidable energy waste or cut their emissions if they know how they use energy and how much direct and indirect GHG emissions are produced.

What data to include? Determining boundaries and scopes of coverage

Before starting to collect energy and carbon data, it is crucial to define the organisational and operational boundaries for such data collection, i.e., what should be included and what can be excluded. When setting the organisational boundaries, either an equity share approach or control approach, the latter defined in either financial or operational terms, could be followed.

Equity share approach

Typically, covering the ownership percentage of energy use and emissions from all the aspects of an organisation that are owned by it (irrespective of whether they are operated or financed by the organisation).

Control approach

Operational control

Covering energy use and emissions from all the aspects of an organisation that fall under its operational control.

Financial control

Covering energy use and emissions from all the aspects of an organisation that fall under its financial control. Usually, this boundary includes fewer GHG emissions than the operational boundary.

Unless an organisation has a very complex structure, the operational control approach is recommended to determine the boundaries. If the company has many subsidiaries, joint ventures or leased assets, then establishing the boundaries may be more complicated, and following either the financial control, or the equity approach may be more appropriate.

Once the organisational boundary is defined, then the scope can be determined, specifying the emission sources that will be included in calculating the organisation’s carbon footprint.

The Greenhouse Gas Protocol defines three scopes of emissions:

Scope and source of emissions
Data collection methods

Scope 1: Directly produced by the organisation or from sources owned by the organisation

Emissions produced though the combustion of fossil fuels for heating or industrial applications, or emissions produced by the organisation’s owned or leased vehicles

Involves calculating emissions based on purchased quantities of fuel such as natural gas

Scope 2: Indirect emissions from electricity consumption, steam, other sources of energy which are purchased

Heated or chilled water from a district scheme, or emissions from electricity purchased from the grid

Involves calculating emissions based on metered electricity consumption (or other sources of energy such as steam, heated or chilled water etc.)

Scope 3: Other indirect emissions from operational activities

Employee commuting, business travel, third-party distribution and logistics, production of purchased goods, waste disposal, emissions from the use of sold products and outsourced activities by customers

Involves calculating emissions based on a wide range of different activity data such as passenger miles for public transport or tonnes of organic waste to landfill



Collecting carbon and energy data

Once the boundaries and scope of energy and carbon to be measured are determined, the process of collecting that data can begin. Careful validation during the data collection is essential as it will allow an energy and carbon manager to effectively carry out all the other relevant practices.

Energy consumption and emissions data should be collected from utility meters, automatic metering, vehicle fleet fuel records, invoices, including bills for purchased good or employees’ business trips and other sources as applicable.

Additionally, data on the relevant variables that may drive energy consumption should be also reviewed, for example weatherExternal temperature is the dominant influence on the consumption of energy for space heating and cooling. External temperature data can be converted into “degree day” values, which provide a measure of how cold or hot the external temperature was in a given place over a particular period such as a week or month. Most up-to-date regional average monthly and annual degree-day (and cooling degree day) values are available free of charge from various internet sources including Heating & Cooling Degree Days – Free Worldwide Data Calculation or production throughput.

During collection and input of the data, checks should be made to confirm the accuracy, completeness and quality of the data.

Data analysis

Data analysis should, among other things, enable an energy and carbon manager to:

Calculating carbon footprint

A carbon footprint is the amount of carbon dioxide (CO2) or carbon dioxide equivalent (CO2-eq) emissions associated with an activity.  It is typically measured over a 12-month period. When choosing the period for measurement, it is best to take into account organisational reporting cycles, which can be used to set the timeframe.

The most common method for calculating the amount of GHGs emitted from a certain source is by multiplying a documented conversion factor States how many kg of CO2/CO2e gas is emitted for every kWh of fuel combusted. Different fuels have different emission factors; those with high carbon content will have a higher emission factor than those with a low carbon content. Hence, coal has a higher emission factor than natural gas, known also as an emission factor, with the activity data This is data related to the activity that is causing the emission of a greenhouse gas. The data is usually derived from utility invoices and receipts. For example, if calculating the Scope 1 emission for a natural gas heating boiler the activity data will be kWh of gas; if calculating the Scope 3 emission for airline travel, the activity data would be flight distance kilometres for the emission source, measured in units. Such activity data could include fuel consumption from combustion (direct emissions), electricity consumption from purchased electricity (indirect emissions) or flight type and distance for air travel (indirect emissions). Consideration must be taken to ensure the units for the activity data and the emission factor are the same as this avoids an error commonly found in carbon footprint calculations.

GHG emissions (kgCO2e) = Activity Data (units) x Conversion Factors (kgCO2e / unit)

For example, GHG emissions for 500 kWh of electricity billed in the UK, based on the government-issued GHG conversion factors for 2022 would be:

Activity data (500 kWh) x Conversion factor (0.19338 kgCO2e/kWh) = 96.69kg CO2e

To compile the total carbon footprint, all emissions should be added up within their respective scope (totals for Scopes 1, 2 and 3 ).

It is important to use a consistent method to ensure an accurate result, particularly if several people will be working on collecting and interpreting the data. The GHG Protocol site provides several tools to calculate emissions in specific industry sectors such as oil and gas, aluminium, cement and a guide for small office-based organisations. The benefit of using these tools is that they have been subject to review by many companies and experts and therefore, they should represent the current best practice.

Want to know more? More detailed information is available in our online training course, Level 1, Certificate in Energy Management Essentials. To learn more, visit Energy Management Training | Energy Institute