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For when things get a bit technical


  • Anaerobic digestion

    Anaerobic digestion is when organic matter such as animal or food waste is broken down to produce biogas – this takes place in an oxygen-free tank called an anaerobic digester.

  • Authorised Supply Capacity (ASC)

    Authorised supply capacity is a level of capacity agreed with the Distribution Network Operator (DNO) and should be set at just above the anticipated maximum demand.

  • Automatic Meter Read (AMR)

    AMR is the term used to describe a system that provides automatic meter readings remotely.

  • Assistance for Areas with High Electricity Distribution Costs (AAHEDC)

    It is a tax to assist remote areas which have relatively high distribution costs. At present only North Scotland receives the subsidy.


  • Business as usual emissions

    The emissions you will continue to emit if your operations continue without any pro-active attempt to reduce them.

  • Biomass

    Plant material that can be used as an energy source. Deemed carbon neutral because the carbon dioxide released when used is balanced by the absorption during plant growth.

  • Balancing Use of System (BUoS)

    Balancing Use of System charges are levied by NGT via the supplier to cover the costs of balancing the National Grid.

  • Baseload

    The load continuously consumed by an electricity system over a period of time.


  • Carbon capture

    The capture of carbon directly from a process or the atmosphere which is stored in a way where it will not enter the atmosphere (usually an underground geological formation such as a dormant oil or gas field).

  • Carbon budgets

    Much like financial budgets, carbon budgets should be set so that your business and everyone connected to it knows the size of allowable carbon emissions per annum.

  • Carbon baseline

    Having calculated an initial carbon footprint, a carbon baseline can be used to measure future reductions.

  • Carbon offsetting

    Is a method where individuals or companies can balance their carbon footprint by investing in global environmental projects.

  • Carbon neutral

    Balancing carbon dioxide emissions with carbon removal usually through carbon offsetting.

  • Carbon footprint

    If the amount of carbon emitted as a result of individual, organisation or community activity.

  • Carbon Dioxide Equivalent (CO2e)

    The term used to standardise the reporting of various greenhouse gases. Each has its own warming potential so mass is converted to a carbon dioxide equivalent.

  • Carbon credit

    A certificate granting the holder permission to emit greenhouse gases. A credit represents one tonne of CO2e

  • C T metering

    Current Transformer metering. Usually for a supply point of 100 amp and above.

  • COP 5 metering

    Code of practice 5 metering. Is commonly fitted to supplies with maximum demands in excess of 100 kW measuring electricity consumption at half-hourly intervals

  • COP 3 metering

    Code of practice 3 metering. Is commonly fitted to supplies with maximum demands in excess of 1,000 kW measuring electricity consumption at half-hourly intervals

  • Contracts for Difference (CfD)

    The government's scheme for supporting low carbon generation. A strike price is agreed based on wholesale rates. If the wholesale price trades below the strike price then the generator receives a top up, if the price is above the strike price the generator pays back the difference.

  • Combined Heat & Power (CHP)

    CHP simultaneously generates useable heat and power in a single process, often installed on the site of industrial plant.

  • Climate Change Levy (CCL)

    Tax introduced in April 2001 and designed to provide an incentive to meet the UK’s environmental commitments made at the Kyoto Conference. The levy is based on the amount of energy supplied to an end user.

  • Climate Change Agreement (CCA)

    An agreement between the government and a business. A reduced rate of CCL Is applied in return for meeting carbon emission targets. Please note that the deadline to apply for a climate change agreement has now passed.

  • Capacity Market (CM)

    Designed to ensure there is no shortage of future electricity generation. supply. It offers a fixed monthly payment to generators so providing an incentive to investors in new generation plant.

  • Calorific Value (CV)

    The amount of energy in a specific volume of gas. It Is usually quoted in megajoules per cubic meter MJ/m3.


  • Distribution Use of System (DUoS)

    Distribution Use of System is a charge levied by a DNO for the distribution of electricity through its local network.

  • Distribution Network Operator (DNO)

    A DNO is the company licensed to delivery electricity from NGT to the meter.

  • Distribution losses

    Charges relating to electrical losses which occur as electricity is transmitted through the lines of the local Distribution Network Operator (DNO).

  • Display Energy Certificates (DECs)

    A DEC shows the energy performance of a building based on actual consumption. They are required for buildings with a floor area of 250 m2 that are accessed by the public and receive funding from the public sector. A DEC must be accompanied by a recommendation report.

  • De minimis

    An electricity supply using less than 33 kWh per day or a gas supply using less than 145 kWh per day averaged over a billing period. De minimis supplies will be subject to 5% VAT and excluded from CCL.

  • Demand Side Response (DSR)

    A scheme where businesses receive payments to reduce their electricity consumption during periods of peak demand.

  • Data logger

    Device fitted to a meter which can record, store and transmit readings and measurements.

  • Data Collector (DC)

    A company responsible for collecting, processing and validating the meter reading data, which is then passed on to the data aggregator.

  • Data Aggregator (DA)

    An agent appointed to aggregate electricity meter reading data received from Data Collectors to forward to suppliers.

  • Daily Metered Customer (DMC)

    A gas supply point with an annual consumption greater than 58,600,000 kWh must be daily metered.

  • Daily Metered (DM)

    A gas supplies point whose consumption is measured each day by means of a data logger.


  • Export metering

    Allows the accurate recording of onsite generated electricity exported to the grid.

  • Energy Performance Certificate (EPC)

    An EPC will show the efficiency of a building using information regarding its design and equipment. An EPC must be displayed if the total useful floor area of a building Is greater than 500 m2.

  • Energy Intensive Industries (EII)

    A government scheme to help large users of energy. EIIs can claim up to 85% exemption on CfD, RO and FiT payments.

  • Embedded generation

    Electricity generation by plant which has been connected to the local Distribution Network Operator's grid rather than directly to the NGT.

  • Extra High Voltage

    Extra High Voltage is electrcity supplied at 33,000 Volts.

  • Energy Savings Opportunity Scheme (ESOS)

    A mandatory energy assessment for any large UK undertaking.


    ELEXON is the company who manages payments between generators, suppliers and traders

  • Electricity Central Online Enquiry Service (ECOES)

    ECOES is the database holding information about electricity meters.


  • Fossil Fuel Levy (FFL)

    Government tax collected by electricity suppliers to fund the decommissioning of nuclear reactors.  Although active, the levy is currently set at zero and has been since 1st April 2002 in England and Wales.

  • Fossil fuel

    Fuels formed by natural processes which contains hydrocarbons. These fuels are burned for energy generation and release greenhouse gas emissions into the atmosphere.

  • Firm gas

    A guaranteed supply of natural gas that will not be subject to interruption.

  • Feed in Tariff (FiT)

    FiT is a scheme designed to subsidise small scale electricity generation.


  • GHG Protocol

    A comprehensive standard framework for measuring greenhouse gas emissions. It splits emissions into three scopes: Scope 1 - directly combusted emissions Scope 2 - emissions from the purchased energy Scope 3 - indirect emissions for your supply chain

  • Ground/air source heat pumps

    Ground/air source heat pumps extract heat from either the ground or the air converting it into energy which can then be used.

  • Greenwashing

    Providing misleading information about a company or product’s green credentials.

  • Greenhouse Gases (GHG)

    The emission of a number of gases that affect the warming of the planet. There are the seven gases included within the GHG Protocol.

  • Green energy

    Energy from renewable sources such as wind or solar.

  • Geothermal energy

    Heat and energy stored in the earth - an example of this is natural hot springs. Cold water is pumped down through the earth and this is heated and pumped back up to the surface.

  • GWh

    1 Gigawatt hour = 1,000 MWh or 1,000,000 kWh

  • Grid Supply Point (GSP)

    Grid Supply Point is the point where electricity transfers from the National Grid to the local distribution network.

  • Gas Distribution Networks (GDNs)

    GDNs are responsible for local distribution of gas to the meter.


  • Hydro energy

    Hydropower is energy created from the movement of water through a turbine.

  • High Voltage (HV)

    High Voltage is electricity supplied at 11,000 Volts

  • HH data

    Half hourly data is electricity consumption data recorded every half hour and collected by the metering system.

  • Half Hourly (HH)

    Any supply with a half hourly meter fitted. Data is recorded every half hour and is used to provide accurate billing and consumption analysis.


  • Interruptible gas

    A gas supply that may be interrupted by NGT or supplier to assist in maintaining pressure through the network during periods of high demand and low supply.

  • Interconnector

    An electricity or gas cross border connector.


  • kWh

    Kilowatt hour is a unit of electricity consumed in an hour.

  • kW

    Kilowatt is measure unit of power equal to 1,000 watts.

  • kVA

    Kilovolt Amperes is a unit of electricity incorporating the reactive power component.


  • Low Voltage (LV)

    Low Voltage is electricity supplied at 240 or 415 volts.

  • Load factor

    Ratio between average usage and maximum demand. Load Factor is calculated by the formula: Load Factor = (total Units / (no. Of Hours x Maximum Demand) x 100% The higher the load factor, the flatter a customer's load shape.

  • Line Loss Factor (LLF)

    Indicator, within MPAN, of distribution line loss for a meter point.


  • Megawatt hour (MWh)

    1 Megawatt hour = 1,000 kWh

  • Meter Point Reference Number (MPRn)

    Unique gas meter reference number. Similar to electricity's Mpan.

  • Meter Point Administration Service (MPAS)

    The organisation responsible for holding all Information on Mpans.

  • Meter Point Administration Number (MPAN)

    Meter Point Administration Number is a unique number assigned to electricity meter by local DNO. Also known as a Supply Number.

  • Meter Operator (MOP)

    A Meter Operator is a company appointed to install and maintain metering equipment.

  • Maximum Export Capacity (MEC)

    Maximum Export Capacity is an agreed capcity for exporting to the grid.

  • Maximum Import Capacity (MIC)

    Maximum Import Capacity - see Authorised Supply Capacity.

  • Meter Operator Agreement

    Agreement between the customer and the nominated meter operator.

  • Maximum Demand (MD)

    The highest usage In a half hourly period over a period of a month or year. This value Is doubled to give the hourly maximum demand. MDs can be measured In kW or kVA.


  • Net zero

    The balance between greenhouse gas produced and the amount removed from the atmosphere. The UK has set a target of being net zero by 2050.

  • Non-Daily Metered (NDM)

    Gas supply point whose meter is not fitted with a data logger and is read monthly, six monthly or at longer intervals.

  • Nominated consumption

    Annual quantity of gas nominated by the customer as their annual estimated consumption requirement.

  • Non Half Hourly (NHH) meters

    A meter which Is not fitted with the equipment to be read half-hourly. These are usually read manually.

  • National Grid (NG)

    Owners of the electricity and gas transmission networks.

  • Network Code (NWC)

    Legal framework that defines the rights and obligations of National Grid and shippers.

  • Natural gas

    Mixture of naturally occurring gasses found either in isolation or in underground reservoirs.

  • National Transmission System (NTS)

    The high-pressure network of pipes that transports gas between the terminals, storage facilities and Local Distribution Zones.

  • National Balancing Point (NBP)

    A virtual point on the gas network where gas is traded.


  • Office of Gas and Electricity Markets (OFGEM)

    The regulator for the gas and electricity industries in Great Britain.


  • Paris Agreement

    A legally binding agreement on climate change between 196 parties, signed in 2016. Its goal is to limit global warming to well below 2°C but preferably 1.5°C.

  • Power Purchase Agreement (PPA)

    A PPA is a long term contract whereby an end user agrees to purchase energy directly from a generator.

  • Power Factor (PF)

    The proportion of total energy supplied to a site, which is actually converted into useful energy output, as opposed to the wasted reactive power.

  • Photovoltaics (PV)

    The conversation of solar radiation into electricity.


  • Renewable Obligation Certificates (ROC)

    Certificates issued to generators for each whole MWh of electricity generated from eligible renewable sources. These can be sold to suppliers so they may meet their renewable obligation.

  • Renewables Obligation (RO)

    An obligation on electricity suppliers to source a specified percentage of the total electricity supplied to their customers in Great Britain is from eligible renewable sources evidenced by Renewable Obligation Certificates (ROC).

  • Renewable Energy Guarantees Origin (REGO)

    A REGO Is a certificate a supplier can use to show electricity has been purchased from a renewable source. 1 REGO = 1 MWh

  • Renewable energy

    Generation of electricity from renewable sources, e.g. wind power or hydro-electricity.

  • Reactive Power (kVARh)

    Power flowing through a circuit without doing any work. It is a chargeable element but can be eliminated with the Installation of Power Factor correction equipment.


  • Solar energy

    Solar energy is energy converted from sunlight through solar panels.

  • Smart Export Guarantee (SEG)

    Introduced in January 2020, the SEG is an obligation set by the government for licensed electricity suppliers to offer a tariff and make payment to small-scale low-carbon generators for electricity exported to the National Grid, providing certain criteria are met.

  • Supply Point (SP)

    A shippers metering facility at the customers premises.

  • Supply Offtake Quantity (SOQ)

    The maximum daily consumption for a given metering point.

  • Supply Hourly Offtake (SHQ)

    The maximum hourly consumption for a given metering point.

  • Streamlined Energy & Carbon Reporting (SECR)

    Introduced in April 2019, SECR is a scheme where large UK companies are obliged to disclose carbon emissions and an efficiency metric in their annual Directors' report.

  • Single phase supply

    A single phase supply has a one wave cycle. More suited to smaller supplies.

  • Shipper

    A company which purchases gas from producers and transports it through the network to customers.


  • Tidal power

    Tidal power harnesses the energy of the sea to create energy.

  • TWh

    1 Terawatt hour = 1,000 GWh or 1,000,000 MWh or 1,000,000,000 kWh.

  • Triad

    Used to calculate TUoS charges. It Is based on the average of consumers highest three demands (kW) at times of peak demand on the grid. Only applicable from 1st November to 28th February.

  • Transportation charge

    The charges associated with transporting gas from the beach to the meter point. Prices are based on a distance related tariff system and vary demanding on interruptible and firm supply.

  • Transmission Use of System (TUoS)

    The charges Incurred by use of National Grid's network.

  • Transmission losses

    Charges relating to electrical losses which occur as power is transmitted via National Grid.

  • Transco

    The former name of National Grid.

  • Three phase supply

    A three phase supply has three wave cycles and is used in commercial and industrial supplies.

  • Therm

    A unit of energy measurement. 1 therm = 29.3071 kWh

  • Tariff

    Published standard charges applied to utility supplies that are not on a negotiated contract.

  • Take or pay

    A contract whereby a customer must pay for a specific quantity of electricity or gas irrespective of usage.



    The United Nations Framework Convention on Climate Change. An international treaty, which started in 1994, that has since supported the creation of the Kyoto Protocol in 1997 and the Paris Agreement in 2015.


  • Voltage

    The unit used to measure the electromotive force of an electric current.


  • Whole Current metering

    Usually for a supply point of 100 amp and below.


  • Xoserve

    Xoserve hold the central register for all gas meters. This includes a list of all MPRns, the supplier and AQ.