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• Table of Contents

Introduction

This document is intended to give a description for both technical and non-technical readers of the nature and methodology of our carbon footprint calculations.

Throughout this document we will describe the algorithms that we use to calculate carbon footprints for clients we work with. However, many businesses have features of their practices unique to them. The algorithms used for calculation of such activity thus requires specific design for the given case and therefore cannot be elucidated here. However, these details can always be found in the report associated with any given calculation. Indeed, if you wish to understand the specifics of any particular calculation, the associated report is the best place to look. Such reports and this document should independently verify the validity, efficacy, and innovative nature of our approach. Having said this, this document will elucidate our approach to such situations and demonstrate the principles by which we conduct our calculations.

All of our calculations follow the Greenhouse Gas Protocol. This is the standard internationally renowned carbon calculations methodology. In our view, a major impediment to the uptake of carbon footprint calculations is the ease of use; without appropriate technology, calculations can take weeks of data collection and calculation. Therefore, we have built our algorithms to standardise data collection from clients making it simple for them to collect the data we need to calculate.

In addition we have built a comprehensive test suite for our calculation software, where changes to the code are validated against peer reviewed and government released carbon footprint data, and an uncertainty calculation module, implementing the pedigree matrix approach. Details can be found at the end of this document.

Key Terms

• Emissions factor — there are multiple green house gasses that contribute to global warming when released into the atmosphere. Their effects differ in magnitude. Therefore, in order to compare different activities, a single unit of measurement is defined, $CO2_e$ (carbon dioxide equivalent), that standardises the impact of the various gasses. An emissions factor is a way of measuring a given activities effect on the planet. For example, the consumption of electricity in the UK from the grid in 2021 has an emissions factor $0.19338[\frac{kgCO2_e}{kWh}]$. If a business wanted to know its emissions associated with its electricity consumption, it would multiply this emissions factor by its kWh consumption over a given time period $x_{elec}[kWh]*e_f[\frac{kgCO2_e}{kWh}] = E_{elec}$ (this would be a location-based as opposed to a market-based calculation. For more details see the electricity section).
• Scope — there are 3 scopes, aptly named scope 1, scope 2, and scope 3. They are ways of categorising the different types of emissions a company creates in its operations.
  • Scope 1 pertains to direct emissions caused by assets owned and operated by the body in question. For instance, the burning of fossil fuels.
  • Scope 2 is indirect emissions caused by the consumption of energy that is generated elsewhere i.e. the use of electricity, heat, steam, or some cooling systems.
  • Scope 3 covers everything else: travel, food consumption, accommodation, use of materials, etc.
• Spend-based method — using the total amount spent on a good or service to calculate the resultant emissions. As many goods and services vary dramatically in price, this methodology should only be used where necessary.
• Activity-based method — using data representative of the fundamental carbon emitting activity to calculate emissions. This is the preferred method of calculation.

Scopes 1 & 2

Gas

Although gas consumption is often part of scope 1, many companies we work with rent their offices, making gas consumption part of scope 2. Therefore, we have grouped scope 1 and 2 to reflect this ambiguity. We then separate scopes 1 and 2 when reporting back to the company depending on the situation of that specific client.

Data

Typically, either the body we are calculating for (client), or a close partner of theirs (e.g. landlord) has access to the kWh of gas consumed. We collect this in our activity spreadsheet for all the premises under the control of the client. In cases were gas is metered for an entire building of which the client only has partial financial control, we typically collect the area under their control and divide it by the total rented area in the building, to get an approximate factor for their usage.

Factors

We take gas emission factors from DBEIS published statistics.

Calculation