When talking ‘energy solutions’ to our clients, we cover a broad range of energy terms that may not be common knowledge. The energy terms glossary below is designed to give some insight into the various definitions and abbreviations that exist within our industry.

Reflecting our commercial renewable energy installation services, this glossary of energy terms focuses on general electrical terms, as well as solar energy- and battery storage-related terminology. If you need any further assistance with the topics covered here, don’t hesitate to get in touch.


The following terms are found within the electrical and energy sectors:

General Electrical Terms

Joule (J) – A unit of energy to measure the force needed to transfer mass from one space to another.

Watt (W) – A unit of electrical power used to quantify the rate of energy transfer.

Kilowatt (kW) – A unit of electrical power equivalent to 1000W.

Kilowatt Hour (kWh) – A measure of electrical energy consumption equivalent to using 1000W (1kW) for a period of one hour (a really important energy term to understand in our sector).

Current – A flow of electricity in an ordered direction.

AC Power – Alternating current that periodically reverses direction, used commonly in power supplies.

DC Power – Electricity that flows in one direction only.

Voltage (V) – A measure of electrical potential; i.e. the strength of an electrical current that’s sent down a cable.

Amps (A) – A unit of electrical current.

Inverter – A piece of equipment that converts direct current (DC) into alternating current (AC) or vice versa.

Transformer – A piece of equipment that modulates the voltage of current so that it can be transferred from one circuit to another that use different voltages (learn more about how transformers are used in HV/LV infrastructure).

Junction Box – A piece of equipment that contains a junction for combining electrical cables.

Breaker – A switch that protects an electrical circuit from damage by automatically stopping the flow of electricity if an overload or short circuit problem is detected.

Earth – Required for a safe installation, the common return path for electrical current in a circuit.

Frequency (Hz) – Measured in hertz (1Hz equals one cycle per second). For example, in the UK AC electricity is at 50Hz.

Triad – The three half-hourly periods of highest electrical demand on the National Grid between November and February every year. Businesses are sampled and billed on this usage every year.

DUoS – Distribution Use of System (DUoS) charges are applied to your energy bill to recover the cost of distributing electricity and maintaining local distribution networks around the UK.

Charge Bands – DUoS is billed across three charge bands known as ‘red’, ‘green’ and ‘amber’. Costs are highest when consuming energy in the ‘red’ periods and lowest in the ‘green’ periods.

DNO – Distribution Network Operators (DNOs) own and operate the cables and towers that bring electricity from the transmission network to businesses around the UK (e.g. Western Power Distribution).


Terms Used in the Solar PV Sector

Solar Panel – A device that uses a number of photovoltaic (PV) cells to capture and absorb the sun’s rays to turn into DC electricity – we install solar panels for businesses as one of our core services.

Mounting Rail – A rail used to mount solar panels on to.

Clamp – Device used to fix solar panels to the rail.

Performance Ratio (PR) – The primary measure of a solar PV system’s efficiency. Performance Ratio (PR) is used to express how effectively the system converts sunlight collected by the solar panels into AC electrical energy.

D-marc Edge Protection – A health and safety measure that makes the working area (roof) of the building safe from falling incidents (D-marc Edge Protection should be utilised on roofs with a pitch of over 15 degrees). 

Safety Rail – A health and safety measure that makes the working area (roof) of the building safe from falling incidents. Safety rails should be utilised if the roof has a pitch exceeding 15 degrees.

Access Ladder – A ladder used for access, generally to the rooftop of a site where solar is to be installed.

O&MOperation and maintenance which refers to our solar panel maintenance service.

Warranty – The assurance given by a manufacturer that a piece of equipment will work to a given standard within a given period – EvoEnergy solar customers are protected by the Independent Warranty Association (IWA).

Weather Station – A collection of devices used to measure weather and ultimately help to understand what the output of a PV system should be at any given time.

This glossary of energy terms has outlined a range of definitions and abbreviations that relate to our core services. If you need any help with the issues raised here or you’d like to talk to us about how our renewable energy services could help your business, then get in touch.