A–Z of Renewable Energy: The Ultimate Glossary by Boston Renewables
The renewable energy sector is full of technical terminology — and understanding it is key to making informed decisions for your business.
At Boston Renewables, we work with organisations across the UK to design, install and maintain commercial Solar PV systems, Battery Energy Storage Systems (BESS) and EV charging infrastructure.
To help you navigate the landscape, we’ve created the ultimate A–Z Renewable Energy Glossary — with practical, business-focused definitions.
A
Accredited Installers
Certified renewable energy specialists meeting recognised industry standards for safety, quality and compliance. The primary accreditation for all electrical infrastructure is administered through NICEIC. The Microgeneration Certification Scheme (MCS) caters for small scale renewable energy installations and solar PV up to 50kW.
Alternating Current – AC
The type of electricity used in UK buildings. Solar PV generates in Direct Current (DC) and so inverters are used to convert DC into usable AC power.
Array
A group of solar panels connected together to form a complete Solar PV system. Arrays can be mounted on roofs, on the ground or on water.
B
Battery Energy Storage Systems – BESS
Technology that stores surplus solar energy for use once the sun has set, or during times of peak demand or grid outages — improving energy resilience and investment returns.
Base Load
The minimum level of electricity demand on a site at any given time. Solar PV arrays are best designed to meet the base load.
C
Carbon Footprint
The total greenhouse gas emissions associated with a business’s operations. Solar PV and BESS installations significantly reduces a site’s carbon footprint.
Commercial Solar PV Installation
Large-scale Solar PV systems designed for warehouses, factories, offices, industrial, agricultural and horticultural premises.
D
Direct Current – DC
DC is a type of electric current that flows in one constant direction, unlike AC that oscillates and can flow in opposing directions.
Solar PV arrays generate electricity in DC and this needs to be converted into alternating current (AC) by an inverter.
Declared Net Capacity – DNC
The maximum output of a solar system, measured in kilowatts (kW) as an aggregation of inverter capacities.
Demand Response
Adjusting electricity usage during peak demand periods to reduce costs and support grid stability. Financial incentives are available for providing demand response.
Decarbonisation
The process of reducing carbon emissions — a key driver behind renewable energy adoption.
E
Estimated Annual Generation – EAG
The predicted total annual amount of electricity expected to be generated by a solar PV array. Usually measured in kilowatt hours – kWh.
Energy Audit
A site assessment identifying opportunities to reduce energy consumption and improve efficiencies.
EV Charging Infrastructure
Electric vehicle charging points installed on commercial premises to support fleet and staff vehicle electrification. Owners of EV chargers can set their own electricity tariff to incentivise uptake of EVs.
Export Tariff
Payment received for exporting surplus renewable electricity generation back to the grid.
Export Limitation
A method used to allow the installation of generating systems in areas of poor grid resilience. See G100.
Energy Networks Association – ENA
UK’s national industry body that coordinates technical standards, policy engagement and engineering guidance for network operators.
F
Frequency
The rate at which an alternating electrical current (AC) changes direction per second. Measured in hertz (Hz), electricity in the UK is distributed at 50Hz +/- 0.5Hz. When generation exceeds demand, frequency rises and vice versa.
Flexibility Services / Frequency Response
Incentivised grid services allowing businesses with battery storage to support grid frequency balancing at 50Hz.
Forecasting
Predicting solar generation output (yield) based on meteorological data, array configuration and system design.
G
Grid Connection
The link between your renewable energy system and the national grid. All renewable electricity generating installations require grid connection agreements.
G99
The UK’s regulatory framework that sets out how electricity generation equipment — like commercial solar arrays, battery storage systems and other generators — must connect to the public electricity distribution network so that safety, reliability and power quality are maintained.
G99 Compliance
Inverters are manufactured to comply with G99 regulations, and this satisfies compliance for the majority of solar installations. In certain circumstances G99 electrical relays are fitted to meet compliance requirements.
G100
UK electricity grid’s technical standard issued by the Energy Networks Association (ENA) that specifically deals with how a customer’s generation or storage installation must limit the amount of power it exports to the public electricity distribution network.
G100 Compliance
Export Power Management (EPM) devices are fitted to monitor a site’s export, and they sequentially shut down inverters to limit export of electricity onto the grid.
Generation Meter
Measures how much electricity a solar system produces.
Green Energy
Power generated from renewable sources such as solar and wind.
H
Hybrid System
A renewable electricity generating system combining solar PV with battery storage.
Hertz – Hz
Unit used to measure electrical frequency.
Half Hourly Data – HHD
Readings recorded every 30 minutes of the import and export of electricity. HHD provides a very accurate picture of a site’s load profile and greatly aids the sizing of solar PV and BESS installations.
I
Inverter
Converts DC electricity from solar panels into usable AC electricity.
Import Tariff
The rate paid for electricity drawn from the grid.
J
Just Transition
Ensuring the shift to renewable energy is economically fair and sustainable.
K
Kilowatt – kW
Unit of electrical power – equivalent to 1000 watts (W).
Kilowatt-Hour – kWh
Unit that measures energy consumption or generation over time.
L
Load Profile
A pattern of electricity usage across a day, month or year. Used alongside base load data to correctly size solar PV and BESS installations.
Levelised Cost of Energy – LCOE
The average cost of generating each unit of electricity over a solar PV system’s lifetime. (System capex + lifetime O&M / lifetime yield. Figure derived expressed as p/kWh)
Lifecycle Analysis
Assessment of environmental impact across a product’s lifespan.
M
Maintenance Package
Ongoing system servicing and performance checks to ensure safe operation and optimal system output.
Microgeneration
Small-scale on site renewable generation.
Microgeneration Certification Scheme – MCS
Industry body that ensures microgeneration installations (eg: solar arrays up to 50kW) are safe, reliable and adhere to industry standards. MCS certification is frequently required to access the Smart Export Guarantee – SEG.
Monitoring System
Integrated hardware used to track flows of electricity and record system faults in real time.
N
Net Zero
The balance of greenhouse gas emissions produced with emissions removed or offset.
National Grid
The UK’s electricity transmission network.
Nominal Power – or Rated Power
The rated maximum output capacity of a solar panel, inverter, BESS or EV charger produced under normal operating conditions.
O
On-Site Generation
Producing renewable electricity at your business premises.
Optimiser
An electronic device that improves solar panel performance at module level. Often used within solar arrays subject to shading.
Off-Grid System
A renewable system operating independently from the grid.
Ofgem – Office of Gas & Electricity Markets
UK’s independent regulator of the gas & electricity markets.
P
Peak Demand
The highest level of electricity consumed or required during a specific time period.
Photovoltaics (PV)
Silicon technology that converts sunlight into electricity as direct current.
Private Wire
Description of a renewable generating station located remotely to the site requiring the electricity and where a dedicated cable links the two sites .
Power Purchase Agreements – PPAs
Agreements entered into between renewable energy generators and electricity supply companies for the purchase of renewable electricity exported onto the grid.
Q
Quality Assurance (QA)
Processes ensuring installations meet required standards.
Qualified Supervisor
A certified and technically competent person responsible for ensuring compliance to safety and regulatory standards in electrical installations.
R
Renewable Energy
Energy derived from naturally occurring and replenishable sources.
Return on Investment – ROI
Financial return achieved through reducing energy bills and receiving export income and monetary incentives.
REGOs – Renewable Energy Guarantees of Origin
Certificates that prove electricity has been generated from renewable sources. REGOs are administered by Ofgem and used to enhance PPAs.
S
Solar PV Arrays
Photovoltaic systems that convert sunlight, and diffused ultraviolet light, into usable power.
Smart Meters
Digital meters used to provide real-time energy data and send readings directly to electricity suppliers.
Sustainability Strategy
A long-term plan to reduce environmental impact.
T
Time-of-Use Tariffs
Variable electricity pricing depending on time of day. Enabled by smart meters, time of use tariffs greatly enhance the financial benefit of BESS installations.
Transformer
An electrical device used to adjust voltage levels either up or down. Typically used in private wire systems to allow smaller cables to transmit large amounts of current.
Turnkey Installation
End-to-end project delivery from design to commissioning.
U
Uninterruptible Power Supply – UPS
Battery-backed power protection system.
Utility-Scale Solar
Large solar farms supplying electricity directly to the grid.
V
Voltage
Electrical potential difference, or ‘pressure’ in a electrical circuit. Think of voltage in the same way as water flowing trough a pipe.
Virtual Power Plant – VPP
Network of decentralised renewable systems operating collectively.
W
Watt (W)
Unit of power measurement.
Watt-Hour (Wh)
Unit of energy measurement.
Wholesale Energy Market
Marketplace where electricity is traded in bulk between major generators.
X
X-Factor in ROI
External influences such as energy price volatility, downtime or system losses that impact on a installation’s predicted profitability.
Y
Yield
Actual electricity production from a solar PV system. Measured in kWh or MWh
Year-on-Year Savings
Financial savings are achieved annually through renewable adoption.
Z
Zero Emissions
Energy generation that produces no operational carbon emissions.
Zero Export Limitation
A system configuration preventing any electricity from being exported to the grid.