Glossary

Here is a guide to some of the technical terms used by TRANSITION. You can also check out the Understanding Flexibility page developed in partnership with Project LEO for definitions of flexibility services.

• Aggregation The bringing together of multiple energy assets (wind, solar, batteries etc) often owned by more than one person, into one combined portfolio to provide a flexibility service.
• Aggregator A company or other body that brings multiple energy assets (e.g. wind, solar, batteries) together and acts as an intermediary between the asset owners and the flexibility market, acting on the owners behalf. An asset owner may choose to use an aggregator to simplify their participation in flexibility markets or because they do not qualify to trade directly in the market.
• Availability Status Whether a Distributed Energy Resource (DER) is ‘Available’ or ‘Unavailable’ to deliver flexible energy at a particular time.
• Available If a Distributed Energy Resource (DER) is asked to, at a specific time, it will be available to deliver flexible energy.
• Baseline We measure the energy that was being produced or used during delivery of a flexibility service by looking at meter data. We compare this to your ‘baseline’, which is what that reading would have been if the service was not being delivered i.e.what the usual generation or consumption of the Distributed Energy Resource (DER) would be at that time.
• Behind the meter Behind the meter refers to usage, generation or storage of electricity inside a property or site, on the energy user’s side of the electricity meter that connects the property or site to the grid. For example, your kettle, wall plugs and and fuse box are all behind the meter. Conversely, anything that happens on the distribution network side of the meter is deemed to be ‘in front of the meter’.
• Constrained connection A type of connection to the electricity network which allows distributed energy resources to connect to the network in a quicker and/or cheaper than normal way, in exchange for allowing the DNO to occasionally manage the import or export of the asset to avoid a constraint on the network.
• Constraint A situation where an imbalance in electricity supply or demand means the network is unable to transport sufficient electricity to meet the electricity demand at a given time and place or that is being produced by a generator.
• Demand Your electricity ‘demand’ represents the rate at which electricity is being used (in kW) at any time or that is needed to run a particular appliance or piece of equipment.
• Demand response Your electricity ‘demand’ is the rate at which you are using electricity. To help the electricity network and to balance this demand against the supply of electricity available locally, you could temporarily reduce the amount of electricity you are using. At times, increasing your demand, particularly when there is an excess of electricity being supplied, can also help balance the network. Both reducing and increasing your demand temporarily to help the network is called a ‘demand response’.
• Distributed Energy Resource (DER) Anything that generates electricity (like a wind turbine) or stores electricity (like a battery) and sends it to your local electricity network (called the Distribution Network) can be called an Energy Resource. If that Energy Resource can temporarily change the amount of electricity it sends to the local network and can do this on request, it is called a Distributed Energy Resource (DER). Similarly, if you have a machine or other piece of electrical equipment (for example air conditioning or electric heaters) that can be turned, on, off, up or down on request, this is also called a DER. DERs have the ability to provide energy Flexibility. Also sometimes called a Distributed Energy Asset.
• Distributed Generation In the past we had large scale energy generators like power station or nuclear power plants which were often located a long way from where the electricity was being used. We have a growing number of smaller scale and more environmentally friendly ways of generating electricity now, such as solar panels and wind turbines. Their generated energy is often used more locally. Energy generated locally to where it is being used is called Distributed Generation.
• Distribution Network This part of the electricity network reduces the higher voltage energy that is delivered to your area by the Transmission Network and uses power lines and other infrastructure to send it to homes and businesses where it is needed. The Distribution Network is also playing an increasingly important role in connecting local DERs to the network.
• Distribution Network Operator (DNO) The Distribution Network Operator, or DNO, is responsible for owning, operating, and maintaining the electrical network in a geographical licence area and delivering electricity to communities and customers throughout the licence area, including, homes, businesses, and industry. A DNO also maintains upkeep and investment in the electricity network to ensure it is functioning and capable of handling electricity demand.
• Distribution System Operation (DSO) A Distribution System Operator, or DSO, plays a key role in coordinating and managing the operation of the distribution electricity system. It securely operates and develops an active distribution system comprising electricity networks, electricity demand and generation management, and other flexible distributed energy resources.
• Electricity Supplier A company that buys electricity from the network, and in turn sells it to domestic, commercial and industrial users. This is who you pay for your energy use.
• Electricity System Operator (ESO) The Electricity System Operator, manages the electricity system and ensures supply meets the required demand. The ESO performs several important functions; from second-by-second balancing of electricity supply and demand, to developing markets and advising on network investments.
• Flexibility Making temporary changes in the way you consume, generate, or store electricity when requested, to support a more efficient use of the energy network.
• Flexibility Provider A flexibility provider is a person or organisation who provides flexibility by making temporary changes to the way they consume, generate, or store electricity when requested.
• Flexibility Service When Flexibility is provided in response to a request, this is described as the person making the change providing a ‘Service’. There are different sorts of services that can be provided depending on the needs of the network. These are explained here.
• Generation Any electricity that is produced. For example by energy assets such as wind, hydro or solar farm.
• Grid Edge The Grid Edge is where people make use of the low voltage power the network delivers to homes, businesses and other organisations.
• Grid Edge Technologies The hardware, software and innovations being developed to people to have a more active relationship with the electricity system and that support the transition to a more decentralised and flexible energy system.
• Minimum Viable System (MVS) A Minimum Viable System (MVS) is the minimum amount of people, technologies and processes we need to test whether an energy flexibility idea or process works as we expect it to. In Project LEO, this can help us to quickly identify or confirm the value of what we are doing before we invest more substantially in time, money and engagement.
• MPAN An identification number for electricity meters.  It can be used to identify the location of the electricity meter on the network, and stands for “Meter Point Administration Number”.
• Smart Grid What makes an energy network into a ‘smart grid’ is the use of digital technologies that support a two-way flow of both electricity and information. This helps the network automatically detect and make decisions about what changes are needed to avoid network problems and for the network to ‘fix itself’ if issues occur. Smart grids are able to interact with people and resources both using and generating electricity to keep the network running smoothly and efficiently. They enable people to become active participants in their network.
• Smart Local Energy System (SLES) Smart Local Energy Systems (SLES) are a new concept.  An SLES is where local and national energy infrastructure, people/communities, and technologies work together to make, move, store, sell, use and conserve energy locally.  A successful SLES creates value to the community it serves, and should respond to the community’s objectives.
• Time of Use (ToU) Tariff A Time of Use (ToU) Tariff is an electricity tariff where the charge made for using electricity changes depending on the time of day.  A “static” ToU Tariff has set times of day when charges differ and is typically used to encourage people to reduce their electricity use at times of regular peaks in demand.  A dynamic ToU Tariff does not have set times of day and the charges depend on how much it costs to generate electricity at any given point.
• Transmission Network Most of us commonly call the transmission system “the National Grid”. Its a high-voltage system designed to move electricity from large power stations around the country to where it is needed.  It is made up of transmission lines, pylons and substations.
• Utilisation Instruction The instruction to a person that tells them when and for how long they need to deliver their Flexibility i.e. when they need to temporarily turn up, down, on or off their electricity generation or demand for electricity.
• Whole System All aspects of the energy system including the electricity system of transmission and distribution networks, generation of electricity, storage, and how energy is used.