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About Energy Essentials

Produced and published by the Energy Institute (EI), the Energy Essentials series aims to explain energy topics in an accurate, concise and accessible format. The guides are intended to promote greater understanding of energy, and are suitable for students, professionals whose work crosses over into the energy sector, or anyone with an interest in energy.

Energy Essentials guides are designed to provide foundation-level understanding with a scientific basis. The information, tailored for non experts, is presented in a format intended to be accessible, neutral and based on sound science. The development of this guide has involved an extensive review and analysis of relevant literature. The document has been through a robust peer review process, with contributions from subject specialists, including professionally qualified Fellows and Members of the EI, with a broad range of backgrounds and experience.

Due to the constantly evolving nature of energy technologies and markets, all data and information is current as of the date of publishing (January 2023). For more information, visit the Energy Institute Knowledge Service, or get in contact using

Other titles in this series

Energy Essentials: A guide to shale gas
Energy Essentials: A guide to hydrogen
Energy Essentials: Transitioning energy-intensive industries to net zero


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.

Baseline energy use: a benchmark against which an entity’s emissions are compared over time. The reporting company’s base-year emission is called baseline. A base year can be the earliest reporting year the company submits a complete emission report or a historical year when the company submits complete data or all subsequent years; it could be a calendar year or a fiscal year.

Carbon footprint: the amount of carbon dioxide (CO2) or carbon dioxide equivalent (CO2-eq) emissions associated with an activity, and, if ongoing, per year. For example, the average carbon footprint of a UK household has been estimated as 26t Co2-eq/y. Of that about a third is a direct emission, e.g., space heating, driving, and hot water, and two-third indirect or embedded emissions, e.g., those arising in the production and shipping of household goods. Some estimates of carbon footprint omit embedded emissions. (Oxford Dictionary of Energy Science)

Carbon management: measuring and managing greenhouse gas (GHG) emissions within an organisation and extending the reduction of emissions across a supply chain (Carbon management: a step by step guide - Paia Consulting)

Conversion/emission factor: it 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.

Energy efficiency: the use of the minimum amount of energy while maintaining a desired level of economic activity or service; the amount of useful output achiever per unit of energy input. The IEA has suggested that energy efficiency should be thought of as the “first fuel” considered for economic development and emissions reduction.

Energy management: it is the continuous process of measuring, understanding and optimizing energy consumption within an organization.

Energy management system (EnMS): it is a set of policies and procedures integrated and put into practice to track, analyse, and plan for energy usage.  It uses the Plan-Do-Check-Act management method of continual process improvement.

Energy Performance Indicators (EnPIs): the overall performance of a building or site can be expressed as a performance indicator, usually measured as kilograms of carbon dioxide per square metre (kg CO2/m2) per year or separately for fossil fuel and electricity measured in kilowatt hours per square metre (kWh/m2) per year. The analysis is normally performed on annual data, allowing for comparison with published benchmarks to give an indication of efficiency. Benchmarks are published for different types of buildings, some energy use applications, e.g. office lighting, and some processes.

Environmental management: it consists of decisions and actions concerning policy and practice regarding how resources and the environment are appraised protected, allocated, developed, used, rehabilitated, remediated, and restored. (Source: I. Petrosillo, R. Aretano, G. Zurlini, Socioecological Systems, in: Encyclopedia of Ecology, Volume 4, 2015, Pages 419-425)

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).

ESG (environmental, social, governance) factors: a set of standards for company’s behaviour used by socially conscious investor to screen potential investments. Environmental criteria consider how a company safeguards the environment, including corporate policies addressing climate change. Social criteria examine how it manages relationships with employees, suppliers, customers, and the communities where it operates. Governance deals with a company’s leadership, executive pay, audits, internal controls, and shareholder rights. (Source: Investopedia)

Financial control approach: 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.

Greenhouse gases (GHG): naturally occurring greenhouse gases include water vapour, carbon dioxide (CO2), ozone (O3), methane (CH4) and nitrous oxide (N2O). They absorb the infrared radiation emitted by the Earth and cause the surface temperature to rise.

GHG emissions: it 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.

Low-carbon: when the CO2 emissions related to a process or activity are small relative to the amount emitted when fossil fuel are the source of energy. For example, a low-carbon economy is one where a high fraction of the energy used is from renewable or nuclear power.

Measurement and verification (M&V): the process of quantifying savings delivered though an energy saving action or measure; enables savings to be properly evaluated.

Monitoring and targeting (M&T): the process of establishing the existing pattern of energy use and its key drivers and variables, and the identification of the desirable level of energy use.

Operational control approach: covering energy use and emissions from all the aspects of an organisation that fall under its operational control.

Scopes of emissions: under the GHG Protocol, the sources of GHG emissions are broken down into three scopes: Scope 1 accounting for direct sources of emissions such as fuel consumption, company vehicle or fugitive emissions, Scope 2 accounting for indirect sources of emission such as purchased or acquired electricity, steam, heat and cooling and Scope 3 accounting for indirect sources of emission such as purchased goods and services, transportation and distribution, and use of sold products.

Sustainability management: it embraces simultaneously economic, social and environmental objectives and impacts. It involves a very wide range of issues, including food and water availability, resources use and depletion, poverty, economic growth, social cohesion, community engagement, production and consumption, climate change, population growth, and international security. (Source: The Energy Hierarchy: Supporting policy making for 'net zero', Institution for Mechanical Engineers).

The Paris Agreement goals: the outcome of the Conference of Parties twenty-first meeting in Paris (COP21 Paris) in December 2015, in which nations reaffirmed the goal of limiting global warming to well-below 2°C above pre-industrial levels and pursuing efforts to limit warming to 1.5°C.


Energy Institute, Energy management training, Level 1: Certificate in energy management essentials, course materials available upon enrolment via Energy Management Training | Energy Institute

Energy Institute, Energy management training, Level 2: Energy management professional, course materials available upon enrolment via Energy Management Training | Energy Institute

Albert, B. (2018), ‘Does the typical carbon management hierarchy apply to your business?’ Available on: Does the typical carbon management hierarchy apply to your business? - 100% Renewables (

Brittain, J., (2018), Tools and techniques to deliver behaviour change The-Discovery-Mill-CPD-article-behaviour-change-tools-and-techniques-Nov18.pdf (

Brittain, J., (2016), Behaviour change for low-cost energy savings, CPD module 02, Series 14, Energy in Buildings and Industry Magazine

Brittain, J., Mulholland, J., Rutter, J., (2021), Plan for behaviour change, EIBI_Series_18_Module_9.pdf (

Carbon Trust, (2011), Energy management. A comprehensive guide to controlling energy use

Carbon Trust, (2019), Effective energy management for business, Available on: Effective energy management for business guide | The Carbon Trust

Carbon Trust, (2022), A guide to carbon footprinting for businesses, Available on: footprint-business-guide-compressed4.pdf (

Carbon Trust, (2013), CTG056 “Creating an Awareness Campaign”, Available on Creating an awareness campaign guide | The Carbon Trust

Carbon Trust, Digital technologies for energy management – a buyers guide, Digital technologies for energy management - a buyers guide | The Carbon Trust

CPD, (2021), ‘Putting a price on carbon. The state of internal carbon pricing by corporates globally’, Available on: Putting a price on carbon - CDP

Department for Business, Energy & Industrial Strategy (BEIS), (2020), ECA756 Automatic monitoring and targeting (aM&T) equipment, ECA756 Automatic monitoring and targeting (aM&T) equipment - GOV.UK (

IEA, (2021), Energy Efficiency 2021, Available on Energy Efficiency 2021 – Analysis - IEA

Jelley, N. (ed), (2019), Oxford Dictionary of Energy Science, Oxford, Oxford University Press

Mulholland, J., (2014) Ten steps to change, Energy in Building and Industry Magazine

Rohinton, E. and Baker, K. (2012), Carbon management in the built environment, Oxon, Routledge

Shelley, W. W. Z. (2020), Carbon management for a sustainable environment, Cham, Switzerland, Springer

Sougata, N. (2022), Energy management in real estate: the secrets to success, 3e advisory

Staddon, S., Cycil, C., Goulden, M.,  Leygue, C., and Spence, A., (2016), Intervening to change behaviour and save energy in the workplace: a systemic review of available evidence, Energy Research and Social Science, Elsevier