Acronyms | Forest Row Energy

Your A-Z Guide to UK Energy & Renewable Acronyms

Navigating the world of energy, gas, water, and especially renewable technologies can often feel like learning a new language! With so many schemes, technical terms, and organisations, the number of acronyms can be overwhelming. At Forest Row Energy, we believe in making sustainable energy accessible and understandable for everyone in our community and beyond.

This comprehensive guide is designed to be your go-to resource for decoding the most common (and some less common!) acronyms you'll encounter. Whether you're considering solar panels, wondering about heat pump grants, trying to understand your energy bill, or just keen to learn more, this A-Z list will help clear up the confusion. We'll cover general energy terms, those specific to electricity, gas, and water utilities, and dive deep into the ever-expanding world of renewable energy.

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General Energy & Utilities Acronyms

Acronym	Full Name	Brief Explanation
AC	Alternating Current	Type of electrical current commonly used in homes and businesses.
AGR	Advanced Gas-cooled Reactor	A type of nuclear reactor.
AMR	Automatic Meter Reading	Technology that automatically collects consumption data from energy meters.
BEIS	Department for Business, Energy & Industrial Strategy	Former UK government department (functions now largely with DESNZ).
BERR	Department for Business, Enterprise & Regulatory Reform	Former UK government department.
BSI	British Standards Institution	National standards body of the UK.
BTU	British Thermal Unit	A traditional unit of heat energy.
CA	Conservation Area	An area of special architectural or historic interest, with stricter planning controls.
CAPEX	Capital Expenditure	Funds used by a company to acquire, upgrade, and maintain physical assets.
CCC	Climate Change Committee	Independent statutory body advising UK and devolved governments on emissions targets and climate change adaptation.
CCGT	Combined Cycle Gas Turbine	A type of power plant that uses both gas and steam turbines to produce electricity more efficiently.
CCL	Climate Change Levy	A tax on energy delivered to non-domestic users in the UK.
CCS	Carbon Capture and Storage	Technology to capture CO2 emissions from sources like power plants and store them.
CCUS	Carbon Capture, Usage, and Storage	CCS plus the utilisation of captured CO2.
CDP	Carbon Disclosure Project	Non-profit that runs a global disclosure system for investors, companies, etc. to manage environmental impacts.
CEC	Community Energy Cooperative	A community-owned and run organisation focused on local energy initiatives (like Forest Row Energy).
CfD	Contract for Difference	Long-term contracts to support low-carbon electricity generation by guaranteeing a price for electricity.
CHP	Combined Heat and Power	Systems that generate electricity and useful heat simultaneously from the same fuel source.
CI	Carbon Intensity	The amount of CO2 emitted per unit of energy or economic output.
CO2	Carbon Dioxide	A primary greenhouse gas.
CO2e	Carbon Dioxide equivalent	A measure used to compare the emissions from various greenhouse gases based on their global warming potential.
COP	Conference of the Parties	Annual UN climate change conferences.
COP	Coefficient of Performance	A measure of the efficiency of heat pumps and refrigeration cycles.
CPA	Climate Protection Act	Legislation aimed at reducing greenhouse gas emissions.
CPRE	Campaign to Protect Rural England	Now 'The Countryside Charity'.
CRM	Customer Relationship Management	Systems and strategies for managing interactions with current and potential customers.
CSR	Corporate Social Responsibility	A company's commitment to manage its social, environmental, and economic effects responsibly.
CTSI	Chartered Trading Standards Institute	A UK professional body for trading standards professionals.
CV	Calorific Value	The amount of heat released during the combustion of a specified amount of a substance.
DC	Direct Current	Type of electrical current often produced by solar panels and batteries.
DECC	Department of Energy and Climate Change	Former UK government department (functions now largely with DESNZ).
Defra	Department for Environment, Food & Rural Affairs	UK government department.
DESNZ	Department for Energy Security and Net Zero	Current UK government department responsible for energy and climate policy.
DHW	Domestic Hot Water	Hot water used for bathing, washing, etc.
DNO	Distribution Network Operator	Companies that own and operate the local electricity networks connecting to homes and businesses.
DR	Demand Response (also DSR)	Actions by end-use customers to change their electricity use in response to price signals or grid needs.
DSM	Demand-Side Management	Initiatives and technologies to encourage consumers to optimise their energy use.
DUoS	Distribution Use of System	Charges levied by DNOs for using the local electricity distribution network.
EA	Environment Agency	UK public body responsible for protecting and improving the environment.
EAC	Estimated Annual Consumption	An estimate of the amount of energy a household or business will use in a year.
EBSS	Energy Bills Support Scheme	A previous UK government scheme to help households with energy bills.
ECC/ECO	Energy Company Obligation	A government energy efficiency scheme in Great Britain to help reduce carbon emissions and tackle fuel poverty.
EDF	Électricité de France	A major energy company.
EE	Energy Efficiency	Using less energy to perform the same task.
EII	Energy Intensive Industries	Industrial sectors that consume large amounts of energy.
ELEXON	ELEXON Limited	Administers the Balancing and Settlement Code (BSC) for the GB electricity market.
EMF	Electromagnetic Field	Physical field produced by electrically charged objects.
EMFR	Electromagnetic Field Radiation	Radiation associated with EMFs.
EMR	Electricity Market Reform	A package of UK government measures to incentivise investment in low-carbon electricity generation.
ENA	Energy Networks Association	The industry body representing electricity and gas transmission and distribution network companies in the UK.
EPC	Energy Performance Certificate	Rates the energy efficiency of a building and provides recommendations for improvement.
EPSS	Electricity Price Support Scheme	Government schemes to mitigate high electricity prices.
EPVS	Energy Performance Validation Scheme	Scheme to ensure accuracy of renewable energy system performance estimates.
ERA	Energy Retail Association	Trade association for energy retailers in the UK.
ESCO	Energy Service Company	A company that provides comprehensive energy solutions.
EST	Energy Saving Trust	Organisation promoting energy efficiency and sustainable energy use.
ETR	Emissions Trading Registry	A system for tracking emission allowances in an ETS.
ETS	Emissions Trading Scheme (e.g., UK ETS)	A market-based approach to controlling pollution by providing economic incentives.
EU	European Union	Political and economic union of member states located primarily in Europe.
EUA	European Union Allowance	Carbon credits within the EU Emissions Trading System.
EV	Electric Vehicle	A vehicle powered by an electric motor, drawing electricity from a battery.
EVSE	Electric Vehicle Supply Equipment	Charging points for electric vehicles.
FAQ	Frequently Asked Questions	A list of common questions and their answers.
FREC	Forest Row Energy Cooperative	Your local community energy cooperative!
FSC	Forest Stewardship Council	Organisation promoting responsible management of the world's forests (relevant for biomass).
GBP	Great British Pound (£)	Currency of the United Kingdom.
GBPN	Global Buildings Performance Network	Network focused on improving building energy performance.
GHG	Greenhouse Gas	Gases that trap heat in the atmosphere, contributing to global warming.
GIS	Geographic Information System	System for capturing, storing, analysing and managing geographically referenced data.
GMB/GBP	Google My Business / Google Business Profile	A tool for businesses to manage their online presence across Google.
GRI	Global Reporting Initiative	Organisation that develops sustainability reporting standards.
GW	Gigawatt	A unit of power equal to one billion watts.
GWh	Gigawatt-hour	A unit of energy equal to one billion watt-hours.
HES	Home Energy Scotland	Scottish Government programme offering free, impartial advice on energy saving.
HIES	Home Insulation & Energy Systems Quality Assured Contractors Scheme	Consumer protection scheme for home energy installations.
HMO	House in Multiple Occupation	A property rented out by at least 3 people who are not from 1 'household' but share facilities.
HND	Higher National Diploma	A higher education qualification in the UK.
HSE	Health and Safety Executive	UK government agency responsible for workplace health, safety and welfare.
HVAC	Heating, Ventilation, and Air Conditioning	Systems used to control the environmental conditions in buildings.
IBG	Insurance Backed Guarantee	An insurance policy that protects consumers if an installer ceases trading.
ICE	Internal Combustion Engine	An engine that generates power by burning fuel within the engine itself.
ICO	Information Commissioner's Office	UK's independent body set up to uphold information rights.
IEA	International Energy Agency	Intergovernmental organisation providing policy recommendations, analysis and data on the global energy sector.
IEE	Institution of Electrical Engineers	Now part of the IET.
IET	Institution of Engineering and Technology	A multidisciplinary professional engineering institution.
IG	Instagram	A social media platform.
IIASA	International Institute for Applied Systems Analysis	An independent international research institute.
ILUC	Indirect Land Use Change	Unintended consequence of releasing more carbon emissions due to land-use changes for biofuel/biomass production.
IP	Ingress Protection	Rating system for the degree of protection provided by enclosures against intrusion.
IPCC	Intergovernmental Panel on Climate Change	UN body for assessing the science related to climate change.
IR	Infrared	A type of electromagnetic radiation used in some heating systems.
ISO	International Organization for Standardization	Develops and publishes international standards (e.g., ISO 9001 for quality, ISO 14001 for environment).
JSNA	Joint Strategic Needs Assessment	Assesses current and future health and care needs of a local population.
KPI	Key Performance Indicator	A measurable value that demonstrates how effectively a company is achieving key business objectives.
kW	Kilowatt	A unit of power equal to one thousand watts.
kWh	Kilowatt-hour	A unit of energy, commonly used for electricity and gas billing (1 kWh = 1 'unit').
LA	Local Authority	Local government body.
LCA	Life Cycle Assessment	Analysis of the environmental impacts of a product or service throughout its entire life cycle.
LCCC	Low Carbon Contracts Company	Government-owned company that is the counterparty to Contracts for Difference.
LCOE	Levelized Cost of Energy	The average net present cost of electricity generation for a generating plant over its lifetime.
LCS	Localised Community Scheme	Energy schemes focused on specific local communities.
LDES	Long-Duration Energy Storage	Energy storage systems that can store and discharge energy for extended periods.
LDC	Lawful Development Certificate	A certificate from a local planning authority confirming a proposed development is lawful.
LED	Light Emitting Diode	An energy-efficient lighting technology.
LEP	Local Enterprise Partnership	Locally-owned partnerships between local authorities and businesses.
LPG	Liquefied Petroleum Gas	A fuel gas which is a flammable mixture of hydrocarbon gases, used in heating and cooking.
LSOA	Lower Layer Super Output Area	A geographic area used for statistical purposes in England and Wales.
MEES	Minimum Energy Efficiency Standards	Regulations setting minimum EPC ratings for privately rented properties.
MHHS	Market-wide Half-hourly Settlement	A change in the UK electricity market to settle electricity use every half hour.
MIS	Microgeneration Installation Standard	Specific standards under the MCS scheme for different technologies.
MPAN	Meter Point Administration Number	Unique identifying number for an electricity supply point.
MPRN	Meter Point Reference Number	Unique identifying number for a gas supply point.
MW	Megawatt	A unit of power equal to one million watts.
MWh	Megawatt-hour	A unit of energy equal to one million watt-hours.
NAEI	National Atmospheric Emissions Inventory	Compiles estimates of air pollution emissions in the UK.
NAPIT	National Association of Professional Inspectors and Testers	UK accreditation body for tradespeople in building services and fabric.
NDRHI	Non-Domestic Renewable Heat Incentive	Government scheme to encourage uptake of renewable heat by businesses and public sector.
NEM	Net Energy Metering	Electricity billing mechanism allowing consumers who generate some of their own electricity to use that electricity anytime.
NESO	National Energy System Operator	The future publicly owned system operator for Great Britain's energy system.
Net Zero	Net zero greenhouse gas emissions	Achieving an overall balance between greenhouse gas emissions produced and emissions taken out of the atmosphere.
NG	National Grid	Operates the high-voltage electricity transmission network in Great Britain.
NGO	Non-Governmental Organization	A non-profit organisation that operates independently of government.
NICEIC	National Inspection Council for Electrical Installation Contracting	UK voluntary regulatory body for electrical contractors.
NIR	Near Infrared	A type of infrared radiation.
NOx	Nitrogen Oxides	Air pollutants produced during combustion.
NPPF	National Planning Policy Framework	Sets out government's planning policies for England.
NPS	National Policy Statement	Statements by government on policy relating to nationally significant infrastructure projects.
NRLA	National Residential Landlords Association	Representative body for private residential landlords in the UK.
OCGT	Open Cycle Gas Turbine	A type of gas turbine power plant.
ODS	OpenDocument Spreadsheet / Ozone Depleting Substances	A file format for spreadsheets / Chemicals that deplete the ozone layer.
OECD	Organisation for Economic Co-operation and Development	International organisation that works to build better policies for better lives.
OEM	Original Equipment Manufacturer	A company that produces parts and equipment that may be marketed by another manufacturer.
Ofgem	Office of Gas and Electricity Markets	The energy regulator for Great Britain.
Ofwat	Water Services Regulation Authority	The economic regulator of the water sector in England and Wales.
OIL	Oil Fired Liquid	Heating oil.
ONS	Office for National Statistics	UK's largest independent producer of official statistics.
OPEX	Operational Expenditure	Ongoing costs for running a product, business, or system.
p/kWh	Pence per Kilowatt-hour	Common unit for pricing energy.
P2P	Peer-to-Peer	Relating to energy trading, direct energy sharing between producers and consumers.
PAH	Polycyclic Aromatic Hydrocarbon	Group of chemical compounds, some of which are pollutants.
PAS	Publicly Available Specification	Standards documents, e.g., PAS 2030/2035 for energy efficiency retrofit.
PAT	Portable Appliance Testing	Process of checking electrical appliances for safety.
PEFC	Programme for the Endorsement of Forest Certification	Global alliance of national forest certification systems.
PHEV	Plug-in Hybrid Electric Vehicle	A hybrid electric vehicle whose battery can be recharged by plugging it into an external electric power source.
PPA	Power Purchase Agreement	A contract between an electricity generator and a buyer.
PR	Public Relations	Managing the spread of information between an individual or an organisation and the public.
PSH	Pumped Storage Hydroelectricity	A type of hydroelectric energy storage.
PTFE	Polytetrafluoroethylene	A synthetic fluoropolymer (Teflon).
PVC	Polyvinyl Chloride	A widely used synthetic plastic polymer.
PWR	Pressurized Water Reactor	A type of nuclear reactor.
QA	Quality Assurance	Maintaining a desired level of quality in a service or product.
Q&A	Question and Answer	A format for discussion or information sharing.
RCD	Residual Current Device	A safety device that quickly breaks an electrical circuit to prevent serious harm from an ongoing electric shock.
RCEF	Rural Community Energy Fund	Government fund to support rural communities in developing renewable energy projects.
RD&D	Research, Development, and Demonstration	Process of advancing technology.
RE	Renewable Energy	Energy from sources that are naturally replenishing.
RECC	Renewable Energy Consumer Code	CTSI Approved Consumer Code providing protection for consumers of renewable energy systems.
REGO	Renewable Energy Guarantees of Origin	Certificates proving that a given share of energy was produced from renewable sources.
RET	Renewable Energy Target	A goal set for the proportion of energy to be generated from renewable sources.
RHI	Renewable Heat Incentive	UK government scheme (now closed to new domestic applicants) to encourage uptake of renewable heat technologies.
RHPP	Renewable Heat Premium Payments	A previous UK government grant scheme for renewable heating.
RoHS	Restriction of Hazardous Substances	EU directive restricting the use of specific hazardous materials in electrical and electronic equipment.
ROI	Return on Investment	A measure of the profitability of an investment.
SAP	Standard Assessment Procedure	The UK government's methodology for assessing and comparing the energy and environmental performance of dwellings.
SBC	Smart Battery Charger	A battery charger that can optimise charging.
SCCC	Smart Combination Combi Condensing	A type of advanced boiler.
SCOP	Seasonal Coefficient of Performance	A measure of the average efficiency of a heat pump over a heating season.
SEDBUK	Seasonal Efficiency of Domestic Boilers in the UK	A former boiler efficiency rating system.
SEER	Seasonal Energy Efficiency Ratio	A measure of air conditioner or heat pump cooling efficiency over a typical cooling season.
SEG	Smart Export Guarantee	UK government scheme requiring licensed electricity suppliers to pay small-scale generators for exported electricity.
SHS	Solar Home System	Small-scale solar PV systems for homes.
SLA	Service Level Agreement	A commitment between a service provider and a client.
SMART	Self-Monitoring, Analysis and Reporting Technology	Often refers to smart meters which record energy consumption and communicate it to the supplier.
SMETS	Smart Metering Equipment Technical Specifications	The standards for smart meters in Great Britain (e.g., SMETS1, SMETS2).
SME	Small and Medium-sized Enterprise	Businesses below certain size thresholds.
SO2	Sulphur Dioxide	An air pollutant.
SOV	Share of Voice	A measure of market share or brand visibility.
SPV	Special Purpose Vehicle / Solar Photovoltaics	A subsidiary company with an asset/liability structure and legal status that makes its obligations secure. / Solar PV.
SRO	Self-Regulating Organisation	An organisation that exercises some degree of regulatory authority over an industry or profession.
SSSI	Site of Special Scientific Interest	A conservation designation for areas of particular interest to science.
STB	Set-Top Box	An information appliance device that generally contains a TV-tuner input.
STP	Sewage Treatment Plant / Standard Temperature and Pressure	Facility for treating wastewater. / Defined conditions for measurements.
SVT	Standard Variable Tariff	A type of energy tariff that is not fixed and can go up or down with the market.
T&D	Transmission and Distribution	The process of transporting electricity from power plants to consumers.
TCFD	Task Force on Climate-related Financial Disclosures	Develops recommendations for climate-related financial risk disclosures.
TES	Thermal Energy Storage	Technology to store thermal energy.
TLP	Traffic Light Protocol	A system for classifying and handling sensitive information.
TOU	Time of Use (tariff)	An energy tariff where prices vary at different times of the day.
TRV	Thermostatic Radiator Valve	A self-regulating valve fitted to hot water heating system radiators.
TSO	Transmission System Operator	Entity entrusted with transporting energy in the form of natural gas or electrical power on a national or regional level.
TWh	Terawatt-hour	A unit of energy equal to one trillion watt-hours.
UFS	Unvented Hot Water Storage System	A type of hot water cylinder.
UGC	User-Generated Content	Content created by users of an online platform.
UIPE	Uninsulated Process Equipment	Industrial equipment lacking insulation, leading to energy loss.
UK	United Kingdom	Country in Northwestern Europe.
UKAS	United Kingdom Accreditation Service	The national accreditation body for the UK.
UKGBC	UK Green Building Council	Organisation campaigning for a sustainable built environment.
UKPN	UK Power Networks	A Distribution Network Operator in the UK.
ULEV	Ultra-Low Emission Vehicle	Vehicles that emit very low levels of pollutants.
UNFCCC	United Nations Framework Convention on Climate Change	International environmental treaty addressing climate change.

Electrical Acronyms

Acronym	Full Name	Brief Explanation
AC	Alternating Current	Type of electrical current typically used in homes and for power transmission.
CCA	Climate Change Agreement	Voluntary agreements made by UK industry sectors with the Environment Agency to reduce energy use and CO2 emissions.
DC	Direct Current	Type of electrical current produced by batteries and solar panels; often converted to AC for home use.
DSO	Distribution System Operator	An evolution of the DNO role, actively managing the electricity distribution network.
ESQCR	Electricity Safety, Quality and Continuity Regulations	Regulations setting standards for electricity supply in Great Britain.
EHV	Extra High Voltage	Very high voltage levels used in electricity transmission.
HV	High Voltage	Voltage levels used in electricity transmission and distribution.
LV	Low Voltage	Voltage levels typically supplied to homes and small businesses.
MV	Medium Voltage	Voltage levels used in electricity distribution.
NGET	National Grid Electricity Transmission	Owns and maintains the high-voltage electricity transmission network in England and Wales.
P2G	Power-to-Gas	Conversion of electrical power to gas fuel (e.g., hydrogen).
P2H	Power-to-Heat	Conversion of electrical power to heat energy.
P2X	Power-to-X	Conversion of electricity to other energy carriers (e.g., hydrogen, synthetic fuels) or products.
PEL	Permissible Exposure Limit	Regulatory limit on the amount or concentration of a substance in the air.
PFC	Power Factor Correction	Technology to improve the efficiency of electrical power usage.
PFR	Power Flow Regulator	Device to control the flow of power in an electrical grid.
PMU	Phasor Measurement Unit	Device that measures electrical waves on an electricity grid.
POC	Point of Connection	The specific point where a generator or user connects to the electricity grid.
SCADA	Supervisory Control and Data Acquisition	System for remote monitoring and control of industrial processes, including electricity grids.
TNUoS	Transmission Network Use of System (charges)	Charges for using the national high-voltage electricity transmission network.
UGS	Underground Gas Storage	Facilities for storing natural gas underground (often relevant for electricity generation from gas).

Gas Acronyms

Acronym	Full Name	Brief Explanation
CNG	Compressed Natural Gas	Natural gas stored under high pressure, used as a vehicle fuel.
CV	Calorific Value	The heating value of gas, i.e., the amount of energy released when a known volume of gas is combusted.
GDN	Gas Distribution Network	The local pipeline networks that transport gas to homes and businesses.
GNI	Gas Networks Ireland	The operator of Ireland's gas network (sometimes relevant for UK-Ireland interconnections).
GPL	Gas Pipeline	A pipeline for transporting gas.
GPRS	General Packet Radio Service	A mobile data service used by some older smart gas meters for communication.
GS(M)R	Gas Safety (Management) Regulations	UK regulations concerning the safe management of gas supply and use.
GSI	Gas Safety Inspection	An inspection to ensure gas appliances and installations are safe.
GSR	Gas Safe Register	The official list of businesses and engineers legally permitted to work on gas appliances in the UK.
GT	Gas Turbine	An engine that uses gas combustion to drive a turbine, often for electricity generation.
HGV	Heavy Goods Vehicle	Large trucks, some of which can be powered by LNG or CNG.
IGEM	Institution of Gas Engineers & Managers	Professional body for the gas industry in the UK and internationally.
LNG	Liquefied Natural Gas	Natural gas cooled to a liquid state for easier storage and transport.
LPG	Liquefied Petroleum Gas	Fuel gases like propane or butane, stored as liquids under pressure.
NGN	Northern Gas Networks	A gas distribution network operator in the UK.
SGN	Scotia Gas Networks (now SGN)	A gas distribution network operator in the UK.
WWU	Wales & West Utilities	A gas distribution network operator in the UK.

Water Acronyms

Acronym	Full Name	Brief Explanation
AADD	Average Annual Daily Demand	The average daily water demand over a year.
AONB	Area of Outstanding Natural Beauty	Designated areas of significant landscape value, which can influence water resource and infrastructure planning.
CCW	Consumer Council for Water	Independent body representing water and sewerage consumers in England and Wales.
CSO	Combined Sewer Overflow	Designed to release excess wastewater and stormwater into water bodies during heavy rainfall to prevent flooding.
DWI	Drinking Water Inspectorate	Regulates public water supplies in England and Wales.
IR	Irrigation Requirement	The amount of water needed for agricultural irrigation.
MCM	Million Cubic Metres	A unit of volume for water.
MLD	Million Litres per Day	A unit of flow rate for water.
NTU	Nephelometric Turbidity Unit	A measure of water cloudiness or haziness.
OFWAT	Water Services Regulation Authority	The economic regulator of the water and sewerage sector in England and Wales.
PPM	Parts Per Million	A unit of concentration.
PSI	Pounds per Square Inch	A unit of pressure.
RAG	Red Amber Green	Status reporting system used in project management and operational monitoring.
SuDS	Sustainable Drainage Systems	Water management practices that mimic natural drainage processes to manage surface water runoff.
TW	Thames Water	Example of a major water and wastewater company in the UK.
UU	United Utilities	Example of a major water and wastewater company in the UK.
WACC	Weighted Average Cost of Capital	Used by regulators like Ofwat to determine allowed returns for water companies.
WAFG	Water Available For Use	The amount of water that is available for supply after accounting for losses and environmental needs.
WFD	Water Framework Directive	EU legislation (retained in UK law) aimed at protecting and improving water quality.
WINEP	Water Industry National Environment Programme	Programme of actions water companies must undertake to meet environmental obligations.
WPS	Water Pumping Station	Facility to pump water from one location to another.
WRMP	Water Resources Management Plan	Plans produced by water companies outlining how they will manage water supplies over the long term.
WTW	Water Treatment Works	Facility where raw water is treated to make it safe to drink.
WWRA	Waste Water Recovery Area	An area where wastewater is collected for treatment and potential reuse.
WWTW	Wastewater Treatment Works	Facility where sewage and wastewater are treated before being discharged or reused (also STW - Sewage Treatment Works).

Solar Acronyms

Acronym	Full Name	Brief Explanation
AIS	Amorphous Silicon	A type of thin-film solar cell material.
BIPV	Building Integrated Photovoltaics	Solar PV materials that are integrated into the building structure itself (e.g., roof tiles, facades).
BOS	Balance of System	All components of a PV system other than the panels themselves (e.g., inverters, mounting, wiring).
CSP	Concentrating Solar Power	Technology that uses mirrors or lenses to concentrate sunlight to generate heat for electricity production.
DHI	Diffuse Horizontal Irradiance	Solar radiation received from the sky (excluding direct sunlight) on a horizontal surface.
DNI	Direct Normal Irradiance	Solar radiation received directly from the sun on a surface perpendicular to the sun's rays.
EVA	Ethylene Vinyl Acetate	A polymer used to encapsulate solar cells within a PV panel.
FF	Fill Factor	A parameter that characterises the electrical quality of a solar cell.
FSL	Free Solar Lease	An arrangement where a company installs solar panels on a property for free in return for the FiT payments.
GHI	Global Horizontal Irradiance	Total solar radiation received on a horizontal surface (direct + diffuse).
HJT	Heterojunction Technology	An advanced solar cell technology combining crystalline silicon with amorphous silicon layers.
IPP	Independent Power Producer	An entity that is not a public utility but owns facilities to generate electric power for sale.
IRR	Internal Rate of Return	A metric used in financial analysis to estimate the profitability of potential investments.
ISC	Short-Circuit Current	The maximum current a solar cell can deliver when its output terminals are shorted.
LCOE	Levelized Cost of Energy	Average lifetime cost of generating energy from a specific source.
LFP	Lithium Iron Phosphate	A type of lithium-ion battery chemistry often used in solar energy storage.
MPP	Maximum Power Point	The operating point on a solar panel's I-V curve where it produces maximum power.
MPPT	Maximum Power Point Tracking	An electronic system in solar inverters that optimises the power output from PV panels.
NCM	Nickel Cobalt Manganese	A type of lithium-ion battery chemistry.
NCA	Nickel Cobalt Aluminium	A type of lithium-ion battery chemistry.
NOCT	Nominal Operating Cell Temperature	The temperature reached by open-circuited solar cells in a module under defined conditions.
PERC	Passivated Emitter and Rear Cell	An advanced solar cell technology that improves efficiency.
PV	Photovoltaic(s)	Technology that converts light (photons) directly into electricity (voltage).
PVGIS	Photovoltaic Geographical Information System	An online tool to estimate solar energy production.
SC	Standard Conditions	Defined conditions for testing and rating PV modules.
SEG	Smart Export Guarantee	UK scheme for homeowners to get paid for exporting surplus solar electricity to the grid.
SPS	Solar Power Satellite	Concept for collecting solar power in space and transmitting it to Earth.
STC	Standard Test Conditions	Laboratory conditions (1000 W/m² irradiance, 25°C cell temperature, AM1.5 spectrum) used to rate PV modules.
SW	Solar Water (heating system)	System using solar energy to heat water (also Solar Thermal).
TOPCon	Tunnel Oxide Passivated Contact	An advanced solar cell technology.
VOC	Volatile Organic Compound / Open-Circuit Voltage	Organic chemicals that easily evaporate. / The maximum voltage a solar cell can produce with no load.

Air Source Heat Pumps Acronyms

Acronym	Full Name	Brief Explanation
ASHP	Air Source Heat Pump	A device that transfers heat from the outside air into a building to provide heating and hot water.
COP	Coefficient of Performance	A measure of a heat pump's efficiency at a specific operating temperature.
DHW	Domestic Hot Water	Hot water for domestic use, often provided by heat pumps in addition to space heating.
EER	Energy Efficiency Ratio	A measure of the cooling efficiency of air conditioners or heat pumps.
GSHP	Ground Source Heat Pump	A system that extracts heat from the ground to provide heating and hot water.
HSPF	Heating Seasonal Performance Factor	A measure of a heat pump's heating efficiency over an entire heating season (mainly US).
HT	High Temperature (heat pump)	Heat pumps capable of delivering higher water flow temperatures, sometimes suitable for older radiator systems.
LT	Low Temperature (heat pump)	Heat pumps that operate most efficiently at lower water flow temperatures, ideal for underfloor heating.
MIS 3005	MCS Standard for Heat Pump Installation	The Microgeneration Certification Scheme standard specifically for the installation of heat pumps.
RHI	Renewable Heat Incentive	UK government scheme (now closed to new domestic applicants) to encourage uptake of renewable heat.
SCOP	Seasonal Coefficient of Performance	A measure of a heat pump's average heating efficiency over an entire heating season (more common in Europe/UK).
SEER	Seasonal Energy Efficiency Ratio	A measure of a heat pump's average cooling efficiency over an entire cooling season.
SPF	Seasonal Performance Factor	Similar to SCOP, measures heat pump efficiency over a season.
WSHP	Water Source Heat Pump	A system that extracts heat from a body of water (e.g., river, lake) to provide heating.

Biomass Acronyms

Acronym	Full Name	Brief Explanation
AD	Anaerobic Digestion	A process where organic materials are broken down by microorganisms in the absence of oxygen, producing biogas.
BACT	Best Available Control Technology	Pollution control standards for industrial facilities, including biomass plants.
BECCS	Bioenergy with Carbon Capture and Storage	Generating energy from biomass and capturing the CO2 emissions.
CHP	Combined Heat and Power	Systems that generate both electricity and useful heat from biomass.
DEFRA	Department for Environment, Food & Rural Affairs	UK government department with oversight of biomass sustainability.
EPA	Environmental Protection Agency	Regulatory agency (e.g., in the US, relevant for international biomass standards).
ESP	Electrostatic Precipitator	A device used to remove particulate matter from flue gases in biomass combustion.
FSC	Forest Stewardship Council	Certification system for sustainably sourced wood products, including biomass fuel.
GFRP	Glass Fiber-Reinforced Polymers	Composite materials sometimes used in biomass plant components (though more common in wind turbine blades).
HETAS	Heating Equipment Testing and Approval Scheme	UK body that approves biomass and solid fuel domestic heating appliances, fuels, and services.
ILUC	Indirect Land Use Change	Emissions caused by converting land to grow biomass feedstocks, displacing other land uses.
MSW	Municipal Solid Waste	Waste from households and businesses, a portion of which can be used as biomass fuel.
PEFC	Programme for the Endorsement of Forest Certification	International organisation for sustainable forest management certification.
PM	Particulate Matter (e.g., PM2.5, PM10)	Air pollutants emitted during biomass combustion.
RDF	Refuse Derived Fuel	Fuel produced from MSW and other wastes, can include biomass components.
SRF	Solid Recovered Fuel	Similar to RDF but typically produced to a higher quality standard.
WID	Waste Incineration Directive (EU)	EU directive (relevant for UK standards pre-Brexit) setting controls for waste incineration plants.

Wind Energy Acronyms

Acronym	Full Name	Brief Explanation
BESS	Battery Energy Storage System	Often co-located with wind farms to store energy and improve grid stability.
CF	Capacity Factor	The ratio of actual energy output over a period to the maximum possible output if operating at full capacity.
EIA	Environmental Impact Assessment	A study to assess the potential environmental consequences of a proposed wind farm or other project.
HAWT	Horizontal Axis Wind Turbine	The most common type of wind turbine, with blades rotating around a horizontal axis.
LCOE	Levelized Cost of Energy	Average lifetime cost of generating energy, often used to compare wind energy with other sources.
MWT	Megawatt Turbine	A wind turbine with a capacity measured in megawatts.
O&M	Operations and Maintenance	Activities related to keeping wind turbines and farms operational.
VAWT	Vertical Axis Wind Turbine	A type of wind turbine where the main rotor shaft is set vertically.
WECS	Wind Energy Conversion System	The overall system that converts wind energy into electricity.
WTG	Wind Turbine Generator	The component of a wind turbine that converts mechanical energy from the rotor into electrical energy.

Hydro Energy Acronyms

Acronym	Full Name	Brief Explanation
HEP	Hydroelectric Power	Electricity generated from the energy of moving water.
HPP	Hydro Power Plant	A facility that generates hydroelectric power.
MHP	Micro Hydro Power	Small-scale hydroelectric power generation, typically less than 100 kW.
PSH	Pumped Storage Hydroelectricity	A type of energy storage where water is pumped to a higher reservoir during off-peak times and released to generate electricity during peak demand.
ROR	Run-of-River (hydro scheme)	A type of hydroelectric scheme that uses the natural flow of a river with minimal water storage.