Energy Infrastructure and Distribution Systems Glossary

The realistic peak load of an electrical installation after accounting for user diversity; used to size networks and connections more realistically than summing individual peak loads.

Capacity appearing “unavailable” due to conservative modelling, lack of real-time data, or queue/process rules, even where operational headroom exists.

electricity generation or storage assets located on a customer’s side of the utility meter, providing power directly to a home, business, or facility without passing through the utility meter.

Co-location refers to the development of multiple energy technologies – typically renewables and storage – behind a shared grid connection point. Most commonly, solar PV is co-located with a Battery Energy Storage System (BESS) as they have complementary generation profiles – solar exporting during the middle of the day, whilst a BESS imports earlier in the day and exports later in the day.

The process and pipeline through which demand and generation projects obtain an agreement to connect to the network; delays can be caused by capacity constraints, process complexity, strategic alignment or readiness requirements.

Physical limitations on the network that prevent the transfer of power from one region to another. Can arise from transmission congestion or equipment limitations, and often require generators to reduce their output to ensure system stability.

A CfD is a long term contract that guarantees low carbon electricity generators a stable revenue by bridging the gap between market prices and pre-agreed strike prices. If the market price falls below the strike price, the LCCC pays the generator the difference, whereas if the market price exceeds the strike price, the generator pays back the excess to the LCCC. This ensures generators have predictable revenue streams with protection from volatile wholesale prices.

The involuntary reduction of electric output to maintain grid stability, usually due to system limitations or constraints. Can occur when renewable energy sources produce more electricity than the grid can handle.

Data centres are the physical facilities, which are primarily dedicated buildings, that house computing infrastructure that is typically used to deliver memory and processing power for artificial intelligence (AI), cloud computing, data storage, and server hosting.

Power required by end users (e.g., buildings, transport, industry).

The ability of a low carbon resource to respond predictably when the energy system needs balancing power.

The movement of electricity at lower voltages over shorter distances to homes, businesses and communities, through smaller pylons and underground cables.

The regulated operator responsible for operating and maintaining the local electricity distribution network and providing connections within its licence area.

Operators with an expanded remit compared to DNOs, which integrate Distributed Energy Resources (DERs) and actively manage and optimise energy flows, as opposed to only managing and operating the physical infrastructure. In the UK, DNOs now perform a range of DSO functions alongside their traditional network-operator responsibilities.

Type of time-of-use tariff in which the price changes more frequently and is linked closely to changing wholesale prices of system conditions. The unit rate fluctuates every 30 minutes. Prices are lower during off-peak hours and higher during peak times.

A temporary UK government intervention to shield households from record-high wholesale energy costs triggered by an energy crisis.

A metric that measures how much energy a building consumes relative to its size. In the UK, EUI is typically expressed in kilowatt-hours per square meter per year (kWh/m²/year).

A circuit that carries electricity from a substation to another substation, a local network or customers. Feeders can comprise overhead lines or underground cables and operate at different distribution voltage levels, such as low voltage, 11 kV or 33 kV.

The reliability and assured availability of power, including during periods of system stress or low renewable output.

The ability to change the timing or level of electricity demand (or generation) to support system balancing and reduce peaks (e.g., smart electric vehicle (EV) charging, energy storage, battery dispatch).

Electricity production (e.g., wind, solar, nuclear, gas), including embedded/distributed generation connected to distribution networks.

A location in the network where electricity is transferred from the high-voltage National Transmission System to a local regional distribution network.

Available spare capacity in a network asset (e.g., substation/feeder) to accommodate additional demand or generation without reinforcement.

A third-party provider accredited to design and build electricity connections infrastructure, often for developers, which may then be adopted by a DNO or IDNO.

A licensed company that can own and operate distribution network assets (often installed by an ICP) and recover revenue via network charges.

Electricity generated from natural sources like wind and solar that fluctuate in availability due to environmental conditions.

The ability of different energy systems, technologies, devices, data, markets and energy types to work together and adapt to change, enabling consumers to switch between options and allowing value and information to flow efficiently across the energy system.

Practice of moving electricity consumption from periods of high demand to periods of lower demand, without reducing the amount of energy you use.

A wholesale electricity pricing system in which the lowest-cost electricity sources are used first to meet demand. The price is generally set by the most expensive generator needed to meet demand during that period, meaning consumers do not necessarily pay the cost of the cheapest electricity source.

A major infrastructure development in England and Wales that requires a Development Consent Order (DCO). Typically involves large-scale projects related to energy, transport, water, road and rail.

The infrastructure that transports electricity – transmission (high voltage, long distance) and distribution (lower voltage, local).

An arrangement in which a users interaction with electricity network is assessed by their highest level of import or export during a defined period. A short period of high demand may determine the required network capacity, access rights or charge.

The highest level of electrical power required by a grid or building during a specific period – the maximum instantaneous load.

A long-term contract (typically 5 to 25 years) between an electricity generator and a buyer. The buyer agrees to purchase a specified amount of energy at a pre-negotiated price directly from the producer, providing financial stability for new renewable projects.

A direct electricity connection between a generator and a consumer, bypassing the public electricity network.

A type of connection that provides an initial capacity and a commitment to increase the available capacity in line with an agreed schedule, until reaching the capacity applied for. Designed for when the connection use is expected to increase over several years.

Upgrading the infrastructure to increase the network’s capacity to support additional demand or generation.

A digitally enabled electricity network that uses two way communication and live data to manage the flow of power between generators, the grid and consumers. It integrates advanced technology to enhance the efficiency and flexibility of electricity distribution, allowing for better management of renewable energy sources and reducing energy costs.

Ratio comparing the price of a unit of electricity to a unit of natural gas.

A controlled facility in the power grid that transforms voltage levels, switches and protects circuits, and routes electricity between transmission and distribution networks.

Electricity tariff that charges different prices depending on when electricity is used. Periods usually set in advance and remain consistent day to day or week to week.

A users interaction with he electricity grid is assessed across a defined pattern of time periods, taking account of when and how electricity is imported or exported.

An electrical device that uses electromagnetic induction to transfer energy between circuits and adjust AC voltage levels – either stepping voltage up for efficient long distance transmission or stepping it down for safe local distribution and commercial/residential use.

The movement of electricity at high voltage over long distances across the country, typically through large pylons and overhead lines.

Utility-scale solar refers to large solar power plants, typically ground-mounted photovoltaic (PV) systems, designed to generate electricity for the power grid. These solar farms are much larger than residential or commercial rooftop systems, often ranging from 1 megawatt (MW) to over 1 gigawatt (GW), supplying electricity to thousands of homes, businesses, and industries.

In simple terms, utility-scale solar means big solar farms producing clean energy to power many consumers through the grid.

The changing mix and profile of electricity generation or demand sources on the power system.

A technology that allows electric vehicles to send stored energy back to the grid through bidirectional charging infrastructure. This helps balance electricity demand during peak times.

A system which aggregates multiple, small renewable energy generators, BESS and smart tech into a single collective, controlled by a company. This allows participants to provide electricity to the grid, helping to balance supply and demand, and earn money for their participation.