Glossary
Business Energy & Water Glossary
Energy contracts come with a lot of jargon — kVA, deemed rates, calorific value, half-hourly settlement. Suppliers rarely stop to explain any of it. This glossary does. Each entry gives you a plain-English definition, a worked example where numbers help, and answers to the questions businesses actually ask. No sales pitch, just the explanation.
Every term links to a full entry. We add new entries regularly — if something on your bill isn’t covered here, our business energy bill guide walks through a typical bill line by line, and our guides library covers the bigger topics in depth.
A
An AMR meter, short for Automatic Meter Reading, is a UK gas or electricity meter equipped with a da…
The estimated amount of gas your site uses in a year, and the figure suppliers price your contract on.
Half-hourly metered UK electricity supplies have a critical number recorded in their connection agreement called Authorised Supply Capacity (ASC)…
B
Back billing is when a UK energy supplier recovers charges for energy consumed in earlier periods that was previously under-billed…
You’ve got a dozen sites, a renewal coming up, and someone has mentioned that fixing everything on one Tuesday feels like a coin toss…
A Battery Energy Storage System, almost always shortened to BESS, is a system that stores electrical energy in rechargeable batteries for later use…
Checking each line of an energy bill against your contract and meter data to catch overcharges.
BREEAM, the Building Research Establishment Environmental Assessment Method, is the UK sustainability assessment method for buildings…
You will not spot BSUoS as its own line on most business electricity bills, yet it is quietly baked into the rate you pay…
C
How much energy your gas contains — used to convert meter units into the kWh you are billed for.
A capacity charge is a daily fee per kVA of Authorised Supply Capacity, levied on half-hourly metered UK electricity sites…
The Capacity Market, often shortened to CM, is a UK government scheme that pays generators and deman…
Carbon intensity is the quantity of carbon dioxide (CO2) or carbon dioxide equivalent (CO2e) emitted per unit of output…
A carbon offset is a tradable certificate representing the reduction, avoidance, or removal of one t…
What happens to the energy account when a business moves in or out of premises.
CHP, Combined Heat and Power (also called cogeneration), is the simultaneous generation of electricity and useful heat from a single fuel source…
A Climate Change Agreement, almost always shortened to CCA, is a voluntary agreement between a UK in…
The government tax on business energy use, who pays it, and the exemptions available.
Commercial EV charging refers to electric vehicle charging infrastructure installed at UK business premises…
A commercial heat pump is an electric heating system that extracts heat from the air, ground, or wat…
Commercial solar PV is photovoltaic generation installed on commercial premises (rooftops or ground-…
Contracts for Difference, almost always shortened to CfD, is the main UK government scheme supporting new low-carbon electricity generation…
The cooling-off period is a defined window after signing a UK business energy contract during which …
Once a business draws enough power, a normal electricity meter can no longer cope with the current running through it…
D
Gas supplies where consumption is read every day, typically for larger sites.
The Data Collector, or DC, and the Data Aggregator, or DA, are the UK industry parties responsible f…
Day and night rates are a two-rate electricity tariff structure that charges different unit rates depending on the time of day…
The DCC, short for Data Communications Company, is the regulated entity that operates the central sm…
De minimis is the UK regulatory threshold below which a business energy supply qualifies for the red…
A Display Energy Certificate, shortened to DEC, shows the actual operational energy use of a public building over the past 12 months…
The default prices you pay when you use energy at premises without a signed contract.
Demand Side Response, almost always shortened to DSR, is the practice of UK business electricity cus…
When something goes wrong with the electricity supply to your premises, the first call you’ll probably make is to your supplier…
DUoS, short for Distribution Use of System, is the charge for using the local electricity distribution network…
E
ECOES, the Electricity Central Online Enquiry Service, is the central industry database that holds t…
A tariff with cheaper overnight electricity, and when it actually suits a business.
The Energy Intensive Industries (EII) Scheme is the UK government programme compensating energy-inte…
Elexon is one of those energy-industry names that never appears on a bill but shapes what ends up on one…
An energy audit is a structured assessment of how energy is used at a site or across an organisation…
The Energy Ombudsman is a free, independent service that settles complaints between energy customers…
An Energy Performance Certificate, almost always shortened to EPC, is the UK statutory rating of a building energy efficiency…
If your business is large enough, energy efficiency is not just good practice, it is the law. ESOS, the Energy Savings Opportunity Scheme…
A billed figure based on predicted use rather than an actual meter reading.
If you’ve ever opened a business electricity bill and seen a line called “excess capacity charge” or…
F
If your business installed solar panels, a small wind turbine, or a micro hydro system before 1 April 2019…
The closing bill when you switch supplier or leave premises, and how to check it.
A fixed-rate contract is a business energy agreement that locks in your unit rate and standing charge for the whole of the contract term…
Flexible procurement is a way of buying business energy in stages on the wholesale market over time,…
G
The calculation that turns gas meter units into the kWh on your bill.
Three different companies touch your business gas before it reaches your meter, and most people only ever hear about one of them…
The UK gas year runs from 1 October to 30 September each year. The cycle is chosen to align with the…
A green tariff is a UK business electricity contract under which the supplier matches the customer c…
H
Meters that record consumption every 30 minutes, mandatory for larger supplies.
Find My MPRN is the practical process of identifying the unique 6 to 10 digit Meter Point Reference …
I
An indexed energy contract links the unit rate to a published wholesale market index (the GB day-ahead market for electricity…
ISO 50001 is the international standard for energy management systems (EnMS). Organisations certifie…
K
Your site’s agreed electrical capacity, and why exceeding it costs money.
The basic unit of energy billing — what one kilowatt-hour actually represents.
L
A Letter of Authority, usually shortened to LOA, is a written document that gives a third party (mos…
The regional gas network your site sits in, which affects your unit rate.
M
Maximum demand is the highest half-hourly electrical load that a business site has drawn over a defined period…
MCS, the Microgeneration Certification Scheme, is the UK quality assurance scheme for small-scale re…
MEES, the Minimum Energy Efficiency Standards, are UK regulations restricting the letting of commerc…
A Meter Asset Manager, almost always shortened to MAM, is the UK industry party responsible for installing, maintaining, replacing…
The company that installs and maintains your electricity meter under a MOP contract.
Every UK gas and electricity meter has a unique identifier baked in by the manufacturer called the Meter Serial Number…
A micro-business is a regulated category of small energy customer defined by the regulator, Ofgem. A…
If you’ve ever needed to switch supplier, sort out a meter problem, or set up electricity at a new site…
If you’ve ever switched gas supplier, set up a new lease, or had to chase a billing query, someone will have asked you for your MPRN…
N
When a broker tells you gas prices are up, the number moving in the background is almost always the NBP…
The National Transmission System, almost always shortened to NTS, is the high-pressure gas pipework …
NESO, the National Energy System Operator, is the publicly owned body that operates the high-voltage…
Net zero is the point at which the greenhouse gases an organisation emits are balanced by an equal amount removed from the atmosphere…
Getting power to a new building, or more power to an existing one, is a job in its own right, separate from choosing who supplies the electricity…
Non-daily metered (NDM) gas is the metering arrangement used for most UK business gas supplies. Meter reads are taken periodically (annually…
Most UK business electricity meters live in a quiet middle ground called non-half-hourly settlement.…
UK electricity bills carry small but rising charges that nobody can see, switch away from, or directly negotiate…
O
Ofgem is the Office of Gas and Electricity Markets, the government regulator for the gas and electricity sectors across Great Britain…
The default rates charged after a fixed term ends with nothing new agreed.
P
A pass-through contract is a business energy agreement that fixes the wholesale cost of the energy but lets the non-commodity costs…
Power factor is one of the more technical things on a business electricity bill, and also one of the few where a physical fix can pay for itself…
A Power Purchase Agreement, or PPA, is a long-term contract under which a business buys electricity …
Behind every UK non-half-hourly electricity meter sits a little industry parameter called the profile class…
R
Of all the technical concepts on a UK business electricity bill, reactive power is the one that confuses people the most…
Certificates that prove a unit of electricity came from renewable generation.
The Renewables Obligation, usually shortened to RO, is a UK government scheme that requires licensed…
A rollover contract is a new fixed-term business energy contract that a supplier creates automatical…
S
Scope 1 emissions are the direct greenhouse gas emissions from sources owned or controlled by an organisation…
Scope 2 emissions are the indirect greenhouse gas emissions from the generation of purchased electricity, heat, steam…
Scope 3 emissions are all indirect greenhouse gas emissions in an organisation value chain that are not included in Scope 2…
SECR, the Streamlined Energy and Carbon Reporting framework, is a UK mandatory reporting requirement introduced in April 2019…
A single-phase supply is the basic UK electricity supply configuration. Power is delivered through one live conductor and one neutral…
A sleeved PPA is a structure used in corporate Power Purchase Agreements where a licensed electricit…
The Smart Export Guarantee, almost always shortened to SEG, is the UK government scheme that require…
A smart gas meter does one thing that quietly fixes a lot of billing headaches: it sends your supplier accurate readings automatically…
A SMETS2 smart meter is the second-generation UK smart meter standard, defined in the Smart Metering Equipment Technical Specification version 2…
Supply Offtake Quantity, almost always shortened to SOQ, is the maximum daily volume of gas a UK sup…
Open any UK gas or electricity bill and one of the first lines you see is the standing charge. It is…
What happens to your supply and credit balance when an energy supplier fails.
T
A termination notice window is the period before the end of a fixed-term business energy contract du…
The older imperial unit of gas energy, still used in wholesale pricing.
If you’ve ever walked into a small office and seen the same kind of fuse board you have at home, you’ve seen single-phase…
TM44 is the UK technical methodology for inspection of air conditioning systems with an aggregate rated cooling output above 12 kW…
Every unit of electricity your business uses travels down the motorway of the grid, the high-voltage…
Triad refers to the three specific half-hour settlement periods in each winter (1 November to 28 Feb…
U
A UK business energy bill has two main building blocks and the unit rate is the one tied directly to your consumption…
V
If you’ve ever opened a renewal letter and seen your unit rate jump 30% overnight, you’ve felt the downside of a variable-rate contract…
When you pay 20%, when the reduced 5% rate applies, and how to claim it back.
Voltage optimisation is the installation of equipment that reduces the incoming UK electricity supply voltage to a lower…
Volume correction is the adjustment applied to UK gas meter readings to account for differences in t…
W
The Energy Bill Relief Scheme (EBRS) was the UK government scheme providing temporary discounts on b…
The Energy Bills Discount Scheme (EBDS) was the UK government scheme providing reduced business energy support from 1 April 2023 to 31 March 2024…
X
The central data service behind the GB gas market, and why it matters when switching.
These entries cover the terminology. For how contracts, pricing, and switching actually work, see our business electricity, business gas, and business water pages.