Glossary of terms - Business energy and utilities

This comprehensive glossary provides clear and concise definitions of key business energy terms, helping you better understand energy consumption, billing, and contracts. From kilowatt hours (kWh) to smart meters, our glossary simplifies complex energy jargon to empower your business with the knowledge needed for informed energy decisions.

AMR (Advanced Meter Reader)

Meters capable of transmitting readings to energy suppliers, not to be confused with Smart Meters.

AQ (Annual Quantity)

Industry term to describe the annual consumption of a gas meter in units / kWhs.

Availability

The maximum amount of electricity the grid can supply a single meter in any given half hourly period. This is measured in kVa.

Calorific Value (CV)

The amount of energy released when gas is completely combusted under specified conditions.

Capacity

See Availability.

Change of tenancy (Commonly referred to as a COT)

A change in responsibility for the payment of energy costs at a given premises, this cancels existing contracts and places the incoming tenant on a higher ‘Deemed’ tariff.  Find out more about what a Change of Tenancy means for your business

Climate Change Levy (CCL)

Government tax levied on businesses using an amount of energy over a set threshold to incentivise the use of renewable energy to increase efficiency and reduce carbon emissions.

Contracts for Differences (CfDs)

Replacement for RO (Renewable Obligation). Mechanism for top-up payments to renewable plants when electricity price is below a set level.

Correction Factor

The measure used to adjust gas meter volumes read by meters to account for differences in gas volume due to ambient temperature variation.

Data Aggregator (DA)

Industry body that collates meter reading data to identify the demand level trend.

Data Collector (DC)

Companies that collect readings both physically and remotely before sending them on to suppliers and the Data Aggregator (DA).

Deemed rates

A standard tariff charged to Change of Tenancy customers who have not agreed a contract with their incumbent supplier, typically up to 40% more than an agreed contract tariff.  Find out what deemed rates mean for your business.

Distribution Network (DNO)

The company responsible for managing and maintaining the transmission network that connects power stations and the national grid to homes and businesses across the UK.

DUoS (Distribution Use of System)

Charges levied to cover the cost of installing and maintaining the local distribution networks.

Economy 7 Meter

A two-rate meter typically offering cheaper power between 12am and 7am when demand on the grid is lower.

EAC (Estimated Annual Consumption)

Industry term to describe a forecasted estimate of a given meters consumption over the year.

Evening Weekend & Night Meter

A three-rate meter measuring day, evening and weekend and night usage. Evening consumption generally starts at 7pm and runs to midnight when night consumption takes over

Feed in Tariff (FIT)

Payments made by suppliers to micro and small renewable energy and micro Combined Heat & Power (CHP) generators. The charge is levied to all businesses and is usually included in the tariff you pay with the exception of SSE.

Half Hourly Data

Data read every half hour from specialised meters. This is usually available in the form of a spreadsheet from your current supplier.

Half Hourly Meter (HH Meter)

Specialised meter that transmits reads every half hour to the Data Collector (DC).

Incumbent supplier

The current supplier of a given gas or electricity meter

kVA (Kilo volt amperes)

Unit to measure the difference between real and apparent power where an electrical system is not 100% efficient (ie. has a power factor of less than 1).

kWh (Kilowatt hour)

A kilowatt hour is a unit of energy equal to using 1,000 watts for one hour. It’s used to measure electricity directly, and gas indirectly - gas is first measured in volume and then converted into kWh for billing. Both electricity and gas bills show your usage in kWh.

Line Loss Factor (LLF)

A 3-digit code which makes up part of your overall supply number, used to describe the loss of power in transmitting energy, and more importantly your TCR banding.

Maximum Demand Meter (MD Meter)

Defunct class of meter formerly installed in high consuming premises but rendered obsolete. All former MD meters have been upgraded to Half Hourly meters.

Meter advance

The difference between two meter readings.

Meter Asset Manager (MAM)

For gas, a Meter Asset Manager is the company responsible for the installation, maintenance, and removal of the gas meter at a property. They ensure the meter is safe, compliant, and functioning correctly.

Meter Asset Provider (MAP)

The entity that owns the meter installed in a premises.

Meter Operator (MOP)

The collective name for the MAM and MAP: the owner and maintainer of the meter installed in a premises.

Meter Serial Number (MSN)

Individual number of a gas or electricity meter used to identify the meter. Multiple MSNs can be assigned to a single supply point.

Meter Time Switch Code (MTC or MTS)

A three-digit code which makes up part of your supply number and is used to describe the various time periods in which a meter will register consumption of electricity.

Micro Business

Defined by OFGEM as a business that meets one of the following criteria: uses under 100,000 kWh of electricity, 293,000 kWh of gas, fewer than 10 staff or turns over less than €2m.

M Number or MPRN (Meter Point Reference Number)

Unique reference number applied to the gas supply point in a premises.

MPAN (Meter Point Administration Number)

Your MPAN, also known as a ‘Supply Number’ or ‘S Number’, is a unique 21-digit code linked to your electricity meter. It contains important details about your meter type and supply point.  Find out more about how an MPAN affects your business

National Grid

The company that owns the electricity transmission network and the gas pipeline network that links energy producers to the Distribution Network (DNOs). 

Ofgem

Energy industry regulator responsible for mediating between supplier and customer and ensuring the market works fairly and competitively.

P272

Regulatory change which altered the way business energy use is metered, leading to many meters being upgraded to Half Hourly meters.

Pass Through Charges

Elements of the energy price that can be changed and passed through under the contract terms e.g. levies, transportation and metering costs. 

Profile Class

Two-digit number that makes up part of your overall supply number and describes the pattern of a meter’s electricity usage. Find out more about how a profile class affects your business.

Profile Class 1

A standardised load profile for domestic unrestricted customers using a single rate meter.

Profile Class 2

A standardised load profile for domestic unrestricted customers using an economy 7 two-rate meter.

Profile Class 3

A standardised load profile for non-domestic unrestricted customers using a single rate meter.

Profile Class 4

A standardised load profile for non-domestic unrestricted customers using an economy 7 two-rate meter.

Reactive Power

A charge applied when energy is wasted due to an inefficient electrical system at the customer's site. The level of inefficiency is measured as the power factor, a number between 0 and 1. Low power factors often result in higher charges but can usually be improved by installing a capacitor.

Registration

The industry process by which a customer is transferred from their incumbent supplier to their new supplier.

Registration Window

The 28-day period prior to the intended transfer date within which the new supplier applies for registration of the supply.

Regulator

See Ofgem.

Renewables Obligation (RO)

Requirement by the government that all UK electricity suppliers source a certain percentage of their power from renewable sources, managed through Renawable Obligation Certificates (ROCs).

Renewable Obligation Certificates (ROCs)

Certificates traded by suppliers and generators of energy to certify the generation of eligible renewable electricity. Operators can trade ROCs with other parties and ROCs are ultimately used by suppliers to demonstrate that they have met their obligation.

Shipper

The entity that arranges for the gas transporter to move the gas from the producer to the customer.

Smart Meter

Meters that automatically pass accurate meter readings to energy suppliers and which support other functions, including enabling smart appliance operation.

Supply Number

21-digit number usually appearing in 4 boxes on your electricity bill, used to define the supply point and the characteristics of the meter associated therewith. Find out more about how a supply number affects your business

TPI (Third Party Intermediary)

Usually a broker or consultant acting on behalf of customers and suppliers to arrange energy contracts and assist in the administration of energy supplies. 

TNUoS (Transmission Use of System)

Charge based on your share of demand on the transmission network during its peak periods (Triads), charges vary by length and location but typically represent 7% of your energy bill.

Top Line

The first 8 digits of your supply number containing Profile Class, Meter Time switch Code and Line Loss Factor. 

Transco

Part of the National Grid, the company that owns the gas pipeline network of the UK.

Triad

The three highest half-hourly periods of demand annually used to determine Transmission Use of System (TNUoS) charges to large consumers of energy.