Baseline year
The year your emissions are measured against. A Carbon Reduction Plan reports it alongside your latest year, so reductions can be seen.
Carbon Reduction Plan (CRP)
A public document reporting your Scope 1, 2 and selected Scope 3 emissions and committing to net zero. Required for major UK government and NHS contracts. Read our Carbon Reduction Plan guide.
CO2e
Carbon dioxide equivalent. The seven greenhouse gases added together, each weighted by how much warming it causes compared with CO2.
Conversion factor
A number that turns an activity, such as a kWh or a litre, into kg CO2e. The UK government publishes a new set each June. Read our 2026 factors guide.
DESNZ
The Department for Energy Security and Net Zero, which publishes the UK government conversion factors. Older sets were published by DEFRA and BEIS.
Evergreen
The NHS sustainable supplier assessment. NHS Supply Chain tenders need Level 1 from 6 April 2026. Read our NHS supplier guide.
GHG Protocol
The international standard for measuring and reporting greenhouse gas emissions. It defines Scopes 1, 2 and 3.
Intensity ratio
Emissions divided by a measure of business size, such as tonnes CO2e per £1 million turnover. SECR requires at least one.
Location-based Scope 2
Electricity emissions worked out with the average grid factor, whatever tariff you are on.
Market-based Scope 2
Electricity emissions worked out from your actual tariff. A renewable tariff backed by REGO certificates can count as zero.
Net zero
Cutting emissions as far as possible and balancing what is left with permanent removals. PPN 006 asks for a commitment to reach it by 2050.
Net Zero Commitment
A short published statement, approved by a director, committing to net zero by 2050 or earlier. The NHS asks for one on contracts of £5 million a year or less.
Operational control
The most common way to decide what is in your footprint: everything your organisation runs day to day, whether you own it or lease it.
PPN 006
The Cabinet Office procurement policy note that asks for Carbon Reduction Plans on government contracts above £5 million a year. It replaced PPN 06/21 in February 2025.
REGO
A Renewable Energy Guarantee of Origin: a certificate proving a megawatt hour was generated from renewable sources.
Scope 1
Direct emissions from things you own or control: gas boilers, company vehicles, fuel burned on site and refrigerant leaks.
Scope 2
Indirect emissions from the electricity, heat and steam you buy.
Scope 3
All other indirect emissions in your value chain, in fifteen categories, from purchased goods to business travel, commuting and waste.
SECR
Streamlined Energy and Carbon Reporting: the UK law requiring large companies and LLPs to publish energy use and emissions in their annual report. Read our SECR guide.
Transmission and distribution (T&D) losses
Electricity lost in the grid between the power station and your meter. Reported in Scope 3, category 3.
Well-to-tank (WTT)
Emissions from extracting, refining and transporting a fuel before you use it. Reported in Scope 3.