Reference
Grid connection glossary
The terms you will meet in applications, connection offers and the reformed connections process, defined in plain English.
- Battery energy storage systemBESS
- A battery installation that imports and exports electricity, so it needs both import and export capacity in its connection agreement.See also: G99
- Behind the meter
- Generation or storage installed on the customer's side of the meter, used to serve on-site demand before any power is exported to or imported from the grid.See also: Private wire
- Bilateral Connection AgreementBCA
- The contract between NESO and a user directly connected to the transmission system, setting out the connection terms and capacity.See also: Transmission Entry Capacity
- Connection offer
- A formal offer from a network operator setting out the point of connection, capacity, connection date, works required, cost and terms for connecting a site. Offers are time-limited and must be accepted within the stated validity period.See also: Point of connection, Contestable works
- Connections reform
- The overhaul of how Great Britain allocates grid capacity, led by NESO and approved by Ofgem, which replaced 'first come, first served' with a process that prioritises projects that are ready to build and aligned with national energy plans.See also: Gate 2, National Energy System Operator
- Contestable works
- The parts of a connection that can be designed and built by an accredited ICP rather than the DNO. Non-contestable works, such as final connection to the existing network, are reserved for the DNO.See also: Independent Connection Provider
- Distribution Network OperatorDNO
- The company licensed to run the electricity distribution network in a geographic area, from 132kV (in England and Wales) down to low voltage. Great Britain has 14 licence areas, owned by a small number of groups; Northern Ireland has one.See also: Independent Distribution Network Operator, Transmission Owner
- Export limitation
- A control scheme that keeps a site's export to the grid below an agreed limit, allowing a connection where the network cannot accept the full output of the installed generation.See also: G100, Flexible connection
- Flexible connection
- A connection that may be curtailed or constrained at certain times in exchange for an earlier or cheaper connection, typically managed through an active network management scheme.See also: Export limitation
- G100
- Engineering Recommendation G100, covering export limitation schemes that cap how much a site exports to the network, often used to connect generation where full export capacity is not available.See also: G99, Export limitation
- G98
- Engineering Recommendation G98, the simplified 'connect and notify' process for small type-tested generation, typically up to 16A per phase.See also: G99
- G99
- Engineering Recommendation G99, the Energy Networks Association requirements for connecting generation (including battery storage) in parallel with a GB distribution network. It sets technical, protection and testing requirements by generator type.See also: G100, G98
- Gate 2
- The second stage of the reformed GB connections process run by NESO. Projects that meet the Gate 2 readiness criteria (such as secured land rights) and strategic alignment tests receive a confirmed queue position, connection point and date. Projects that do not meet them are not given a firm place in the queue.See also: Connections reform, Connection offer, Queue position
- Independent Connection ProviderICP
- An accredited company that can build the contestable parts of a new connection instead of the DNO, often giving the customer more control over cost and programme.See also: Contestable works, Independent Distribution Network Operator
- Independent Distribution Network OperatorIDNO
- A licensed network operator that owns and operates distribution networks, usually built for new developments, which connect to a host DNO's network.See also: Independent Connection Provider, Distribution Network Operator
- National Energy System OperatorNESO
- The publicly owned body that operates Great Britain's electricity system and manages applications for transmission connections, including the connections reform process.See also: Transmission Owner, Gate 2
- Point of connectionPOC
- The location on the existing network where a new connection joins it, such as a specific substation or circuit. The point of connection largely determines the cost and timescale of a connection.See also: Connection offer
- Power systems study
- Engineering analysis, such as load flow, short-circuit, harmonics or stability studies, used to show how a connection will behave on the network and to meet the operator's technical requirements.See also: G99
- Private wire
- A direct electrical connection between a generator and a consumer that does not use the public network, for example a solar farm supplying an adjacent factory.See also: Behind the meter
- Queue position
- A project's place in the order in which network capacity is allocated. Under the reformed process, queue order depends on readiness and strategic alignment rather than application date alone.See also: Gate 2
- Transmission Entry CapacityTEC
- The maximum amount of power a generator or storage site is contracted to export onto the transmission system. TEC is held under the Connection and Use of System Code (CUSC).See also: National Energy System Operator, Bilateral Connection Agreement
- Transmission OwnerTO
- The company that owns the high-voltage transmission network in an area: National Grid Electricity Transmission in England and Wales, SP Transmission in southern Scotland and SSEN Transmission in northern Scotland.See also: National Energy System Operator, Distribution Network Operator