The world of energy can sometimes feel like it’s full of complicated terms and technical language. Whether you’re looking into renewable energy, community power projects, or ways to make your home or business more energy efficient, you’re bound to come across words and phrases that aren’t part of everyday conversation.

That’s why we’ve put together this energy glossary – a handy guide to help you make sense of the key terms you’ll come across in our work at Low Carbon Hub. From ‘demand response’ to ‘smart grids’ and ‘flexibility services’, these are the concepts shaping the future of energy in Oxfordshire and beyond.

Whether you’re just starting to explore community energy or already working on a project, we hope this makes things a little clearer.

Energy Glossary

A

Aggregator: An entity that combines multiple energy assets, such as wind, solar, or batteries, often owned by different individuals or organisations, into a single portfolio to provide flexibility services.​

Availability status: Indicates whether a distributed energy resource (DER) is ‘available’ or ‘unavailable’ to deliver flexible energy at a specific time.

B

Baseline: The standard level of energy consumption or generation of a DER under normal conditions, used as a reference point to measure changes during the delivery of a flexibility service.

Battery storage: A system that stores electricity, usually from renewable sources, for later use. Helps balance supply and demand and supports grid stability.

Behind the meter: Refers to the usage, generation, or storage of electricity on the consumer’s side of the electricity meter, within a property or site, as opposed to the distribution network side.

C

Carbon footprint: The total amount of greenhouse gases, particularly carbon dioxide, that are emitted directly or indirectly by an individual, organisation, event, or product throughout its lifecycle.

Carbon neutrality: Achieving net zero carbon emissions by balancing emissions with carbon removal or offsetting.

Carbon offsetting: Compensating for emissions of carbon dioxide or other greenhouse gases by participating in schemes designed to make equivalent reductions of these gases in the atmosphere.

Circular economy: An economic system aimed at minimising waste and making the most of resources by reusing, repairing, refurbishing, and recycling.

Community energy: Energy projects that are owned and run by local communities, aiming to deliver social, environmental, and local economic benefits. This is the focus of Low Carbon Hub’s work – from generating electricity at Sandford Hydro to installing rooftop solar on schools and businesses across Oxfordshire.

Constrained connection: A type of connection to the electricity network that allows distributed energy resources to connect more quickly or cheaply, in exchange for permitting the distribution network operator (DNO) to occasionally manage the import or export of the asset to avoid a network constraint.​

Constraint: A situation where an imbalance in electricity supply or demand means the network is unable to transport sufficient electricity to meet demand at a given time and place, or to accommodate the electricity being produced by a generator.​

D

Decentralised energy: Energy generated close to where it is used, rather than relying on large centralised power stations.

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: Adjusting electricity usage to help balance the grid. This can involve temporarily reducing or increasing demand based on supply conditions.

Distributed energy resource (DER): Any asset that generates or stores electricity and can send it to the local electricity network, or any equipment that can adjust its electricity consumption on request, thereby providing energy flexibility.

Distributed generation: The generation of electricity from sources that are often smaller in scale and located closer to where the electricity is used, such as solar panels or wind turbines, as opposed to large, centralised power plants.

Distribution network: Infrastructure that delivers electricity from the transmission network to homes and businesses.

Distribution network operator (DNO): The organisation responsible for owning, operating, and maintaining the electricity distribution network in a specific area, delivering electricity to industrial, commercial, and domestic users on behalf of electricity suppliers.

Distribution system operation: The management of the distribution network to ensure efficient and reliable electricity delivery.

E

Electricity system operator (ESO): The entity responsible for the minute-to-minute operation of the transmission system, ensuring it is balanced and stable.

Energy assessment: An evaluation of a building’s energy use to identify opportunities for efficiency improvements and cost savings.

Energy efficiency: Using less energy to perform the same task or produce the same outcome, thereby reducing energy waste. An energy efficiency assessment helps you plan ahead by identifying which measures will bring the greatest benefit to your company, organisation, or home.

EV: Electric vehicle, powered by electricity instead of fossil fuels.

F

Feed-in tariff: A policy mechanism designed to encourage the adoption of renewable energy sources by providing payments to energy users for the renewable electricity they generate and feed into the grid.

Flexibility service: A service that involves changing the generation and/or consumption pattern of a DER in reaction to an instruction, to support the efficient operation of the electricity network.

Fuel poverty: When a household struggles to afford adequate heating due to low income and high energy costs.

G

Generation: The production of electricity, typically from power plants or renewable energy sources.

Grid congestion: When electricity demand exceeds the network’s ability to deliver it efficiently, potentially leading to constraints or higher costs.

Grid edge: The part of the electricity network closest to end users, including local generation and consumption.

GW (Gigawatt): A unit of power equal to 1,000 megawatts or 1 billion watts. It is used to describe the output of very large power sources, like major power stations or national energy use.

H

Heat pump: A heat pump is an efficient, low-carbon heating system that uses electricity to move heat rather than generate it. Air source heat pumps draw heat from the outside air, while ground source heat pumps extract it from the ground. Which heat pump is right for you?

I

Insetting: The practice of reducing emissions within a company’s own supply chain or local area rather than through offsetting.

K

kW (kilowatt): A unit of power equal to 1,000 watts. It measures how much energy is being used or produced at a given moment.

L

LETI (London Energy Transformation Initiative): A network of built environment professionals providing guidance on designing and retrofitting buildings to achieve net zero carbon. LETI’s frameworks are widely used across the UK to inform best practices in energy efficiency, low-carbon construction, and reducing embodied carbon in buildings.

Load shifting: Moving electricity use to different times of the day to take advantage of cheaper or greener energy.

M

Maximum export capacity (MEC): The maximum amount of electricity that can be exported to the distribution network, as specified in the connection agreement for a site.​

Maximum import capacity (MIC): The maximum amount of electricity that can be imported from the distribution network, as specified in the connection agreement for a site.

Microgrid: A small, localised energy system that can operate independently or connect to the main grid, often incorporating renewable generation and storage.

MW (Megawatt): A unit of power equal to 1,000 kilowatts or 1 million watts. It is used to measure large amounts of power, such as for industrial use or power stations.

N

Net zero: Achieving a balance between the greenhouse gases emitted into and removed from the atmosphere, resulting in no net increase in atmospheric greenhouse gas concentrations.

Nominal value: The face value of something, not adjusted for inflation or other factors.

O

Onshore wind: Wind turbines located on land that generate electricity from wind power.

Off-grid: A system or property that is not connected to the main electricity network and relies on its own energy generation and storage.

P

Passive house (Passivhaus): A building standard that prioritises ultra-low energy use through high insulation, airtight construction, and efficient ventilation.

Peak management: The practice of reducing or shifting energy demand during periods of high electricity use.

Peer-to-peer energy trading: A system where individuals or businesses can buy and sell locally generated electricity directly, often using blockchain or digital platforms.

Peer-to-peer (P2P) services: Flexibility services traded directly between market actors, excluding the DNO, DSO, or ESO, although these entities may facilitate the trade.​

Prosumer: A term combining ‘producer’ and ‘consumer’, referring to premises where individuals or organisations both consume and produce electricity, such as through the use of solar panels.

Power purchase agreement (PPA): A contract between an energy producer and a buyer, specifying terms for the sale of electricity generated by a renewable energy installation.

Primary substation: A major point in the electricity network where voltage is reduced for distribution to smaller substations.

R

Renewable energy: Energy sourced from natural processes that are replenished faster than they are consumed, such as solar, wind, and hydroelectric power.

Retrofit: Upgrading an existing building with new technology or insulation to improve energy efficiency and reduce carbon emissions. An example of such a service is Cosy Homes Oxfordshire.

S

Secondary substation: A smaller substation that further reduces voltage for distribution to homes and businesses.

Smart community energy scheme: A system that enables a community to produce, store, and share energy locally using smart technology.

Smart grid: An electricity network that uses digital technology to monitor and manage energy flow efficiently.

Smart meter: An electronic device that records energy consumption in real-time and communicates this information to both the energy supplier and the consumer, facilitating better energy management.

Smart retrofit: The use of advanced technologies to improve the energy efficiency of buildings through upgrades and modernisations.

SME: Small and medium-sized enterprises, typically businesses with fewer than 250 employees.

Solar PV (photovoltaic): TTechnology that converts sunlight into electricity using solar panels. Businesses can benefit from free installation and support their local community by hosting a solar PV array through Low Carbon Hub.

Sustainability: Meeting present needs without compromising the ability of future generations to meet their own needs, encompassing environmental, social, and economic dimensions.

T

Time-of-use tariff: A pricing scheme where the cost of electricity varies at different times of the day, encouraging consumers to shift their usage to periods of lower demand and lower prices.

Transmission network: The high-voltage system that carries electricity over long distances from power stations to distribution networks.

U

Utilisation instruction: A request to a DER to deliver a flexibility service by modifying its generation or consumption patterns.

V

Virtual power plant (VPP): A network of small-scale, distributed energy resources – such as solar panels, batteries, and electric vehicles – that work together to provide electricity like a traditional power plant.

Voltage: The measure of electrical potential difference, typically associated with the force that drives electric current.

W

Watts: A watt is a unit of power – the rate at which energy is used or produced.
For example, a lightbulb might use 60 watts, while a typical residential solar panel can produce around 250 to 400 watts of power under ideal conditions, with more efficient panels reaching up to 450 watts!

Whole House Plan: A professional service that assesses a home’s energy-saving potential, helping owners plan and budget for improvements.

Z

Zone: A defined area within the electricity network where flexibility services are required to be delivered.

This should cover all the key terms that regularly appear on Low Carbon Hub’s website. If you stumble on any that are not listed here, do let us know!