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Glossary

Here is a guide to some of the technical terms used by Project LEO. Check out our Understanding Flexibility page for definitions of the flexibility services available.

  • Aggregation

    The ability to deliver a Flexibility Service from a portfolio of one or more Distributed Energy Resources (DER) to a Flexibility Market.

  • Aggregator

    A Market Actor who aggregates the Flexibility from a portfolio of Distributed Energy Resources (DERs) that are too small to enter a Flexibility Market in their own right, or whose owners do not wish to access the Flexibility Market directly.

  • Air Source Heat Pump (ASHP)

    An Air Source Heat Pump uses energy from the outside air which is concentrated to heat your property and hot water. Find out more on this video.

  • Approval Test

    A test to determine whether the Distributed Energy Resource (DER) can deliver a specific Flexibility Service.

  • Availability Status

    The status of the Distributed Energy Resource (DER), being either Available or Unavailable.

  • Available

    Indicates a Distributed Energy Resource (DER) is able to deliver a Flexibility Service during a Service Window should a Utilisation Instruction be issued.

  • Balance Responsible Party

    A Market Actor responsible for the financial consequences if the metered level of electricity for a portfolio is different from the forecast level of electricity in a Settlement Period. The portfolio can include Demand, Demand Assets, Generation and Storage Distributed Energy Resource (DERs) and purchases or sales of electricity.

  • Baseline

    The forecast of the Demand or Generation for a Distributed Energy Resource (DER) submitted prior to the Settlement Period in which the Flexibility Service is delivered.

  • Baseline methodology

    The method for comparing the Metering Point data to the Baseline to determine the Flexibility delivered by a Distributed Energy Resource (DER).

  • Behind the meter

    Behind the meter refers to usage, generation or storage on the energy user’s side of the meter. Conversely, anything that happens on the distribution network side of the meter is deemed to be ‘in front of the meter’.

  • Community Energy Scheme

    A collection of individuals or businesses that emphasises local engagement, local leadership and control. The group benefits from collective action to reduce, purchase, manage or generate energy.

  • Connection agreement

    An agreement for a Site to connect to the Distribution Network or Transmission Network which includes the Maximum Import Capacity (MIC) and / or Maximum Export Capacity (MEC).

  • Constrained connection

    A Connection to a Site where a proportion of the Maximum Import Capacity and / or Maximum Export Capacity can be interrupted by the DNO when there is an active Constraint in exchange for a quicker and / or cheaper connection to the Distribution Network. A Constrained Connection is also called an Export Limited Connection or Flexible Connection.

  • Constraint

    A restriction on the Distribution Network or Transmission System to transport the desired electricity flow in a defined area due to equipment limitations which may vary with the level of Demand or Generation.

  • Constraint Management Service Provider

    A Market Actor who contracts with the Electricity System Operator (ESO) or Distribution System Operation (DSO) to provide constraint management services.

  • Consumer (domestic)

    Domestic premises where the people living or working in it collectively consume electricity, e.g. Demand is more than Generation (which may be zero). The electricity meter will usually have an MPAN (Meter Point Administration Number – a unique 21 digit reference to identify the location of a meter on the Distribution Network).

  • Demand

    The electricity consumption or usage of an item of plant, appliance, machinery, equipment or property.

  • Demand asset

    A Distributed Energy Resource (DER) that can change its demand following an instruction to deliver a Flexibility Service.

  • Demand response

    Modifying generation and/or consumption patterns in reaction to an external signal to provide a service within the energy system.

  • Discretionary Flexibility Service

    The delivery of a Flexibility Service by a Distributed Energy Resource (DER) either (i) during a Discretionary Service Period or (ii) that requires a change in the level of Flexibility to be delivered compared to the Utilisation Instruction.

  • Discretionary Service Period

    The delivery of a Flexibility Service by a Distributed Energy Resource (DER) outside of a Service Window – the period of time an asset is committed to delivering a flexibility service.

  • Discretionary Utilisation Instruction

    A request to deliver a Discretionary Flexibility Service.

  • Distributed Energy Resource (DER)

    A Demand Asset, Generation asset or Storage asset connected to the Distribution Network that may be able to provide Flexibility.

  • Distributed Generation

    A Generation asset on a Site connected to a Distribution Network or an independent distribution network. Also referred to as Embedded Generation.

  • Distribution Network

    A network that carries electricity from the Transmission System/Network and Distributed Generation / Embedded Generation to industrial, commercial and domestic users and operates at 132kV and below (England and Wales) or below 132kV (Scotland).

  • Distribution Network Operator (DNO)

    The organisation that owns, operates and maintains the Distribution Network in one of 14 regional areas that delivers electricity to industrial, commercial and domestic users on behalf of Electricity Suppliers.

  • Distribution System Operation (DSO)

    The functions and services needed to run a smart electricity distribution network in the interests of all Consumers / Prosumers. DSO functions will be delivered by a range of parties.

  • Dynamic Service

    A Flexibility Service that delivers Flexibility after an unplanned outage or fault has occurred.

  • Electricity Network

    The Distribution Network owned and operated by the Distribution Network Operators and the functions and responsibilities of the Distribution System Operator.

  • Electricity Supplier

    A Market Actor that buys electricity or Generation that has to be transported on the Transmission System and /or Distribution System/Network for delivery to industrial, commercial and domestic users.

  • Electricity System

    The Transmission System owned and operated by the transmission operators and includes the balancing responsibilities of the Electricity System Operator.

  • Electricity System Operator (ESO)

    The Market Actor with the responsibility for the minute-to-minute operation of the Transmission System and transmission network, ensuring it is balanced and stable.

  • Embedded Generation

    A Generation asset on a Site connected to a Distribution Network or an independent distribution network. Also referred to as Distributed Generation.

  • Export Limited Connection

    A Connection to a Site where a proportion of the Maximum Import Capacity (MIC) and / or Maximum Export Capacity (MEC) can be interrupted by the DNO when there is an active Constraint in exchange for a quicker and / or cheaper connection to the Distribution Network. An Export Limited Connection is also called a Constrained Connection or Flexible Connection.

  • Fast Follower

    Project Term – A fast follower is an organisation (usually a local authority or local NGO) that wishes to learn from LEO in order to accelerate the setting up of a Smart Local Energy System in their own area.

  • Flexibility

    Changing the generation and/or consumption pattern of a Distributed Energy Resource (DER) in reaction to an instruction to deliver a Flexibility Service.

  • Flexibility Market

    A market where Flexibility is traded between buyers and sellers, usually a Local Market, Regional Market or National Market.

  • Flexibility Service

    A service that delivers Flexibility from a DER within a Zone.

  • Flexible Connection

    A Connection to a Site where a proportion of the Maximum Import Capacity (MIC) and / or Maximum Export Capacity can be interrupted by the DNO when there is an active Constraint in exchange for a quicker and / or cheaper connection to the Distribution Network. A Flexible Connection is also called a Constrained Connection or an Export Limited Connection.

  • Free Bid

    The ability of a Market Actor to offer Flexibility to a Flexibility Market on an ad hoc basis without a contractual obligation to do so.

  • Generation

    The electricity generated or produced by a Distributed Energy Resource (DER).

  • Grid Edge

    The ‘edge’ refers to the points in the electricity grid that are closest to the end users of energy (i.e. at homes and businesses). The term ‘Grid Edge’ is used to encompass the varying hardware, software and innovations being developed at the edge of the network, from behind the meter in premises to the secondary substation, to enable smart local energy systems and consumers to become prosumers.

  • Grid Supply Point

    The interface between the Transmission System and Distribution Network.

  • Ground Source Heat Pump (GSHP)

    Ground Source Heat Pumps (GSHPs) use pipes buried underground (called ground loops or arrays) to extract heat from underground into a fluid which is concentrated to heat your property and hot water. Find out more in this video.

  • In front of the meter

    Any usage, generation or storage that happens on the distribution network side of the meter is deemed to be ‘in front of the meter’. Conversely, Behind the meter refers to usage, generation or storage on the energy user’s side of the meter.

  • Independent Distribution Network Operator (IDNO)

    A licenced party who owns, operates and maintains a private distribution network directly connected to the Distribution Network or indirectly via another IDNO.

  • Intertrip

    A system or process to disconnect a Site from the Transmission System or Distribution Network in very short timescales when a specific event occurs.

  • Last In First Off (LIFO)

    A process of allocating network capacity in an area with a Constraint on the Distribution Network based on the order in which they applied for connection. When there is a Constraint, the MIC / MEC of the most recent customers is reduced more than customers connected earlier.

  • Local Market

    A market for Flexibility Services where Flexibility is required to be delivered to one or more substations within a Distribution Network.

  • Market Actors

    Roles that act or participate in the UK electricity market.

  • Maximum Export Capacity (MEC)

    The maximum amount of electricity (measured by the MPAN) that can be exported to the Distribution Network as specified in the Connection Agreement for the Site.

  • Maximum Import Capacity (MIC)

    The maximum amount of electricity (measured by the MPAN) that can be imported from the Distribution Network as specified in the Connection Agreement for the Site.

  • Meter

    A device that measures the amount of electricity passing through a given point, e.g. MPAN.

  • Metering Point

    The point at which the Flexibility of a DER is measured, being the MPANor a meter installed local to the DER.

  • Microgrid

    Microgrids are independently controlled (small) electric networks, powered by local units (distributed generation). A microgrids can potentially disconnect from the traditional grid and operate autonomously. This offers the users additional resilience in the case of issues such as extreme weather conditions.

  • Minimum Viable System (MVS)

    A Minimum Viable System is the minimum set of participants, technologies and processes required to test a new process modification, asset use case or service. This can identify or confirm new value before investing more substantially in time, money and user relations.

  • MPAN

    Stands for Meter Point Administration Number. A unique 21 digit reference to identify the location of a meter on the Distribution Network.

  • National Market

    A market for trading Flexibility Service nationally.

  • Outage

    Also sometimes called a power cut, a power out, a power blackout, a power failure, a power loss, or a blackout. The loss of the electrical power network supply.

  • Peer-to-Peer (P2P) Services

    Flexibility Services traded between Market Actors (but not the DNO, DSO or ESO although any one of these entities may facilitate the trade), e.g. Offsetting where Flexibility in a Zone is delivered from Demand ahead of the same level of increase of Generation that would exceed the MEC for that Site.

  • Prosumer

    Domestic – premises where the people living or working in it collectively; (i) consume and produce electricity at different times and (iii) produce electricity e.g. has Generation. The electricity meter will usually have an MPAN with Profile Class 01 or 02.

    Non-Domestic – Non-domestic premises where the people living or working in it collectively; (i) consume electricity, e.g. Demand is more than Generation (which may be zero) (ii) consume and produce electricity at different times and (iii) produce electricity, e.g. Generation is more than Demand (which may be zero). The electricity meter will usually have an MPAN with Profile Class 00, 03, 04, 05, 06, 07 or 08.

  • Prosumer (non-Domestic)

    Non-domestic premises where the people living or working in it collectively; (i) consume electricity, e.g. Demand is more than Generation (which may be zero) (ii) consume and produce electricity at different times and (iii) produce electricity, e.g. Generation is more than Demand (which may be zero). The electricity meter will usually have an MPAN with Profile Class 00, 03, 04, 05, 06, 07 or 08.

  • Ramp Down Time

    The time for the DER to remove the Service Capacity at the end of delivering a Flexibility Service and return to its original operating state.

  • Ramp Down Time

    The time for the DER to remove the Service Capacity at the end of delivering a Flexibility Service and return to its original operating state.

  • Re-Bound Effect

    A Demand increase that some Demand Assets experience after the delivery of a Flexibility Service. This normally applies to Demand Assets with thermal characteristics, e.g. air conditioning systems or swimming pools which can increase their Demand as they seek to return to normal operating temperatures.

  • Re-dispatch

    An action the DNO takes to neutralise the energy balance of a Utilisation Instruction within the Zone which may involve a DER outside the Zone.

  • Regional Market

    A market for Flexibility Service that is not a National Market or a Local Market and which may extend over one or more Distribution Network and / or an area of the Transmission System.

  • Restore Service

    A Flexibility Service that uses Flexibility to support restoration of part or all of one or more Distribution Network or Transmission System following a planned or unplanned outage.

  • Scaling Factor

    The revision of the Meter data from a DER to provide the relative contribution to the delivery of a Flexibility Service at the Constraint based on the location of the DER.

  • Secure Service

    A Flexibility Service that delivers Flexibility to address an emerging issue that could result in an unplanned outage or an event if not addressed.

  • Service Capacity

    The Flexibility of a DER that can be used to deliver a Flexibility Service during a Service Window (subject to the Availability Status).

  • Service Recovery Time

    The period after the Ramp Down Time or the end of delivery of a Flexibility Service before the DER can be used to deliver another (or the same) Flexibility Service.

  • Service Response Time

    The time for a DER to achieve a level of Flexibility and start delivering the Service Capacity.

  • Service Stacking

    The ability to use a DER to deliver more than one Flexibility Service within the same or adjacent Settlement Periods, provided it does not interfere with the delivery of the Flexibility Service.

  • Service Window

    The period during which a DER commits to deliver a Flexibility Service in accordance with a Utilisation Instruction.

  • Settlement Party

    The Market Actor responsible for determining the level of Flexibility Service delivered and for settling invoices for the Flexibility Service.

  • Settlement Period

    A period of 30 minutes beginning on the hour or the half-hour. Settlement Periods are defined in the Balancing and Settlement Code and are used to compare a company’s contracted (traded) volume with the metered volume of energy used in the Settlement Period.

  • Site

    The location of a Distributed Energy Resource (DER).

  • Smart Grid

    Distribution Network that can intelligently integrate the behaviour and actions of all users and DER connected to it in order to efficiently deliver sustainable, economic and secure electricity supplies.

  • Smart Local Energy System (SLES)

    Smart Local Energy Systems (SLES) are an emerging concept, both technically and commercially. Broadly, an SLES connects local and national system infrastructure to create an intelligent integrated energy system that delivers value to the community it serves. It can respond to the community’s climate, economic and social aspirations and objectives. A SLES delivers better value to the user and community by taking advantage of innovative approaches to make, move, store, sell, use and conserve energy at a local level.

  • Storage

    An item of plant, machinery or equipment that puts Demand on the network (when charging) or Generation (when discharging) such as a battery.

  • Sustain Service

    A Flexibility Service that delivers Flexibility to address a forecasted need to prevent a critical asset (such as transformer) becoming overloaded.

  • System Security Issue

    A major risk to the integrity of the Electricity System or Electricity Network which could result in the breach of security criteria on the Electricity System and/or Electricity Network. A breach of security criteria includes any unacceptable conditions including unacceptable overloading, unplanned outage or voltage collapse. These include a credible loss of one critical circuit or item of equipment (N-1 Loss) and a credible loss of two critical circuits or items of equipment (N-2 Loss).

  • Time of Use (ToU) Tariff

    A TOU tariff is one that reflects the cost of generating and using electricity at different times. A static ToU tariff charges the same for a unit of electricity at a given time of day and is typically used to disincentivise use at times of regular peak demand; a dynamic ToU tariff reflects the cost of the electricity at any time, depending on prevailing conditions.

  • Trade

    A Peer to peer Service that includes a number of transactions over a period of time, e.g. same group of Settlement Periods every day for one month.

  • Transaction

    A single occurrence of a P2P Service, e.g. Settlement Period, group of Settlement Periods or one day.

  • Transmission Network

    The three regional transmission networks that transport electricity between large Generation stations and Grid Supply Points.

  • Unavailability Notification

    A notification to the Distribution Network Operator stating when a DER will be Unavailable.

  • Unavailable

    Indicates a DER is not available to deliver a Flexibility Service during a Service Window should a Utilisation Instruction be issued.

  • Unmetered Connection

    A connection to the Distribution Network that does not have a Meter where the electricity demand is the number of Demand points multiplied by the consumption of those Demand points, e.g. street lighting.

  • Utilisation Instruction

    An instruction to deliver a Flexibility Service.

  • Voltage of Connection

    The voltage at which the MPAN is metered.

  • Vulnerable domestic customer

    Energy customers significantly less able than ‘typical customers’ to protect or represent their interests in the energy market, as consumer or prosumers with assets that allow them to participate in flexibility provision. They are more likely to suffer detriment, or that detriment is likely to be more substantial. The vulnerability may arise from poor health (physical or mental), visual, audio or other communication difficulties, caring responsibilities, old age, fuel poverty or low income.

  • Vulnerable domestic customer (temporary)

    A temporarily vulnerable domestic customer is vulnerable due to a life event or sudden change in circumstances such as having just left hospital after an operation, dealing with the loss of a loved one or going through a family crisis.

    SSEN have a separate code for, such customers. Read more.

  • Vulnerable non-domestic customer

    A non-domestic customer is considered vulnerable if a power outage would lead to serious consequences for the service it provides or the activities it relies upon to remain in business. Examples would be hospitals and emergency services, laboratories and care homes.

  • Water Source Heat Pump (WSHP)

    WSHPs exchange heat between a water source in the natural environment and a heating and hot water system.

  • Whole System

    The consequences of an operational or investment decision can be considered in terms of the effect on the whole electricity network, not just transmission or distribution networks in isolation from all the equipment connected to the network. This may apply to: the whole electrical system encompassing both transmission or distribution networks, plus all the equipment connected to the networks including generators, demand devices, reactive compensation, energy storage; or all aspects of the energy system including the whole electricity system (transmission or distribution networks), the gas system, fuel transporting and infrastructure, heat networks, and more.

  • Zone

    The location where the Flexibility Service is required to mitigate the identified Constraint on the Distribution Network.

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