UK renewable energy
Renewable energy glossary
55 plain-English definitions covering UK solar, batteries, heat pumps, EV charging, grants, tariffs, certifications and DNO applications. From MCS to V2G to G99.
Solar
(7 terms)- Smart Export Guarantee (SEG)
- UK scheme launched in January 2020 requiring every licensed electricity supplier with 150,000+ customers to pay solar PV owners for surplus electricity exported to the grid. Each supplier sets their own rate (3p-15p/kWh typical in 2026). Replaced the Feed-in Tariff which closed to new applicants in March 2019.
- Feed-in Tariff (FiT)
- UK scheme that ran 2010-2019 paying solar PV owners per kWh generated AND per kWh exported, at rates set centrally and locked in for 20 years. Closed to new applicants 31 March 2019; existing FiT contracts continue for their full term.
- kWp
- Kilowatts peak. The rated DC output of a solar PV system under standard test conditions (1000 W/m² irradiance, 25°C cell temperature). A 4 kWp system typically generates 3,400-3,800 kWh/year in the UK depending on roof orientation and shading. Distinct from kW (instantaneous power) and kWh (energy over time).
- String inverter
- Single inverter handling multiple solar panels wired in series ("string"). Cheapest and simplest solar inverter type. Limitation: if one panel in the string is shaded, the whole string's output drops to that panel's level.
- Microinverter
- Small inverter mounted on the back of each solar panel, converting DC to AC at panel level. Eliminates string-shading losses (each panel operates independently) but costs more than string inverters. Common brands: Enphase, AP Systems.
- Power optimiser
- Device mounted on each solar panel that maximises panel output independently while still feeding a central string inverter. Combines partial benefits of microinverters (per-panel optimisation) with central-inverter cost structure. SolarEdge is the dominant brand.
- Hybrid inverter
- Solar inverter that also handles battery storage management — charges battery from solar surplus, discharges to home loads at peak times. Removes need for a separate battery inverter. Common brands: SolarEdge, Solis, Growatt, Tesla.
Standards & certs
(6 terms)- Microgeneration Certification Scheme (MCS)
- UK quality assurance scheme covering small-scale renewable energy generation (solar PV, wind, heat pumps, biomass, hydro). MCS certification is required for SEG eligibility, BUS grant claims, and most major grant schemes. Verifies installer competence and equipment performance to defined standards.
- NICEIC
- National Inspection Council for Electrical Installation Contracting — UK accreditation body for electrical contractors. NICEIC registration verifies competence to install electrical systems to BS 7671 wiring regulations. Required for EV charger installs.
- Renewable Energy Consumer Code (RECC)
- Voluntary consumer code for UK renewable energy installers, approved by the Chartered Trading Standards Institute. RECC members commit to defined practices for marketing, contracts, payment terms, and complaint resolution. AMP Renewables is RECC registered.
- HIES
- Home Insulation and Energy Systems consumer protection scheme. Similar to RECC — verifies installer adherence to defined consumer-protection practices for home renewable energy installations.
- F-Gas
- EU regulation (retained in UK post-Brexit) controlling fluorinated greenhouse gas refrigerants — including the R32 and R290 used in modern AC and heat pumps. Installers handling refrigerant must hold F-Gas certification. Statutory annual leak checks required on commercial systems above defined capacity.
- Heat Geek certification
- Advanced UK heat pump training and certification scheme. Heat Geek certified installers complete intensive training in heat-loss surveying, emitter sizing, flow-temperature targeting and commissioning. AMP Renewables holds Heat Geek certification.
Battery
(4 terms)- Battery Energy Storage System (BESS)
- Industry term for any battery storage installation — residential or commercial. Includes the battery cells, battery management system (BMS), inverter (or hybrid inverter integration), and control software. Modern residential BESS typically uses LiFePO4 (lithium iron phosphate) chemistry for longevity and safety.
- Emergency Power Supply (EPS)
- Battery feature that automatically isolates from the grid during a power cut and supplies stored energy to critical home circuits. Tesla Powerwall 3 has whole-home EPS built in; SolarEdge BAT-10K needs an additional Backup Interface (£800); Solis S6 + Pylontech supports EPS via the Solis EPS port plus manual change-over switch.
- Lithium Iron Phosphate (LiFePO4)
- Battery chemistry used in modern home batteries (Tesla Powerwall 3, Pylontech US5000, SolarEdge BAT-10K). Longer lifespan (6,000-10,000 cycles vs 2,000-3,000 for older lithium chemistries), better thermal stability (less fire risk), but lower energy density (heavier per kWh) than older NMC chemistry.
- Depth of Discharge (DoD)
- Percentage of battery capacity that can be drained per cycle while still meeting warranty terms. Most modern LiFePO4 home batteries allow 100% DoD (you can use the full rated kWh every day). Older lithium chemistries typically limited to 80-90% DoD to preserve lifespan.
Heat pump
(8 terms)- Air Source Heat Pump (ASHP)
- Heat pump that extracts heat from outside air and transfers it via refrigerant to a water-based central heating system (radiators or underfloor) and hot water cylinder. The most common UK heat pump type. Typical UK residential capacity 4-15 kW; commercial units run 25-150 kW per cascade module.
- Ground Source Heat Pump (GSHP)
- Heat pump that extracts heat from underground via buried collector loops (horizontal trenches or vertical boreholes) and transfers it to central heating. Higher COP than ASHP (4-5 typical vs 3-4) because ground temperature is more stable. Significantly higher install cost due to groundwork.
- Coefficient of Performance (COP)
- Instantaneous heat pump efficiency — ratio of heat output (kWh) to electrical input (kWh). A COP of 4 means 1 kWh of electricity produces 4 kWh of heat. Quoted at specific operating conditions (typically 7°C outdoor / 35°C flow temperature) — real-world averages are usually lower than spec-sheet COP figures.
- Seasonal Coefficient of Performance (SCOP)
- Annual average heat pump efficiency, weighted across all operating conditions in a typical UK winter. More representative of real-world performance than COP. SCOP 4.0+ is excellent; 3.5-4.0 is good; under 3.0 indicates a poorly-designed system or unsuitable application.
- Heat loss survey
- Room-by-room calculation of heat loss rate for a property under design-day conditions (typically -2°C outdoor in the UK), used to size a heat pump correctly. Mandatory for MCS certification. Heat Geek methodology adds additional rigour around emitter compatibility and flow temperature targeting.
- Heat Geek
- Advanced training programme for UK heat pump installers, focused on hydraulic design, controls, flow temperatures and commissioning. Heat Geek-trained installers achieve significantly higher real-world SCOP figures than typical installs. AMP Renewables is Heat Geek-trained.
- Flow temperature
- Temperature of the water leaving the heat pump compressor heading to radiators or underfloor heating. Lower flow temperatures (35-50°C) deliver higher COP but require larger or more numerous emitters. Higher flow temperatures (55-75°C) work with smaller existing radiators but reduce efficiency.
- Cascade heat pump system
- Multiple commercial heat pump units linked together to serve a single larger heat demand. Provides N+1 redundancy (one unit can fail without losing heating) and matches load efficiently across the array. Typical commercial cascade: 4-8 units totalling 200-600 kW.
EV charging
(7 terms)- Office of Zero Emission Vehicles (OZEV)
- UK government body administering EV-related grants including the Workplace Charging Scheme (WCS), Residential Chargepoint Scheme (RCS), and historical Electric Vehicle Homecharge Scheme (EVHS — closed to private homeowners in 2022, retained for landlords and flat owners).
- Vehicle-to-Home (V2H)
- Using an EV battery to power your home via a bidirectional DC charger. Compatible vehicles in 2026: Nissan Leaf, Nissan Ariya, MG ZS EV, BYD Atto 3, BYD Dolphin, Kia EV6, Hyundai Ioniq 5, Renault 5. Bidirectional chargers: Wallbox Quasar 2, JEDI Charger.
- Vehicle-to-Grid (V2G)
- Using an EV battery to export power back to the National Grid for SEG-style revenue. Requires bidirectional charger plus DNO G99 consent plus half-hourly-settlement-compliant meter. Mostly trial-stage in 2026 — commercial fleet deployments common, residential rare.
- Vehicle-to-Load (V2L)
- Lower tier of bidirectional EV functionality — a 13A plug on the car for powering camping equipment, tools, or small appliances. No grid connection. Most VW Group EVs (ID.3/4/5, Cupra Born, Skoda Enyaq) added V2L in 2024 firmware. Distinct from V2H which requires a bidirectional charger.
- Type 2 connector
- EU/UK standard AC charging connector — single-phase 7 kW or three-phase 11/22 kW. Used by all EVs sold in Europe since 2018 (excluding Tesla, which uses a modified Type 2). Older EVs may have Type 1 (single-phase only).
- CCS (Combined Charging System) (CCS)
- European DC fast-charging standard, combining a Type 2 AC connector with two additional DC pins below. Supports 50-350 kW charging. All new EUs sold in the UK since 2020 use CCS for DC fast charging.
- CHAdeMO
- Japanese DC fast-charging standard, predates CCS. Used by Nissan Leaf (all generations) and most pre-2023 Japanese-market EVs. Phasing out in Europe — CCS is the future standard. Still relevant for V2H since Nissan's V2H ecosystem is CHAdeMO-based.
Grants & schemes
(9 terms)- Boiler Upgrade Scheme (BUS)
- UK government grant providing £7,500 (heat pumps) or £9,000 (oil/LPG to heat pump from summer 2026) towards eligible air source or ground source heat pump installations replacing fossil-fuel boilers in residential and some small commercial properties. Application must be made by an fully-certified installer.
- Energy Company Obligation 4 (ECO4)
- UK scheme obligating large energy suppliers to fund energy efficiency measures for low-income households on qualifying benefits or in LA Flex eligibility areas. Funds insulation, heat pumps, and sometimes solar PV (typically only when paired with other measures). Administered through approved installers.
- Home Upgrade Grant (HUG)
- UK grant targeting off-gas-grid households (oil, LPG, electric heating, solid fuel) in lowest EPC bands (D, E, F or G). Up to £15,000 of energy efficiency measures per household. Administered through local authorities — eligibility and process vary by council area.
- Warm Homes Local Grant
- UK government scheme (launched 2025) providing energy efficiency upgrades to lower-income households in qualifying postcodes. Successor to LADS (Local Authority Delivery Scheme). Funds insulation, heat pumps, and sometimes solar PV through council-administered programmes.
- Public Sector Decarbonisation Scheme (PSDS)
- Salix-administered UK grant funding heat decarbonisation in public-sector buildings — schools, academy trusts, NHS estates, councils, emergency services. Provides up to 100% of capital cost for eligible bodies. Phase 4 active 2025-2028; Round 5 expected to open Q3 2026.
- Low Carbon Skills Fund (LCSF)
- Salix-administered grant funding the upfront feasibility, heat-loss survey and decarbonisation pathway consultancy work that precedes a PSDS capital application. Up to 100% of consultancy cost for qualifying public-sector bodies.
- Industrial Energy Transformation Fund (IETF)
- DESNZ-administered grant funding private-sector industrial heat decarbonisation projects (manufacturing, food & drink, chemicals). Feasibility studies up to £7m at 40% intervention rate; deployment grants up to £30m. Particularly relevant for Tees Valley and Wearside manufacturing belt.
- Salix Finance
- Government-owned non-departmental public body that administers PSDS, LCSF and several other UK public-sector decarbonisation grants. Also offers interest-free finance to public-sector bodies for energy-efficiency projects where grant funding isn't available.
- Annual Investment Allowance (AIA)
- UK tax allowance letting businesses deduct 100% of qualifying capital expenditure (up to £1m/year) from taxable profits in the year of purchase. Commercial solar, battery, EV charging, heat pump and boiler installations all qualify. Stack with capital allowances for maximum tax efficiency.
Tariffs
(3 terms)- Time-of-Use tariff (ToU)
- Electricity tariff that charges different rates at different times of day — typically cheap overnight (00:00-05:30 at 7-9p/kWh) and expensive at peak (16:00-19:00 at 25-32p/kWh). Examples: Octopus Go, Intelligent Octopus, EDF GoElectric, Cosy Octopus.
- Half-hourly settlement (HHS)
- Industry-standard method for measuring and billing electricity in 30-minute intervals. Required for time-of-use tariffs and SEG payments. A SMETS2 smart meter records HH data automatically and sends it to your supplier via the DCC.
- Octopus Outgoing
- Octopus Energy's SEG tariff. Outgoing Fixed pays 15p/kWh for all exported solar/battery electricity (highest flat rate in the UK). Outgoing Agile pays a variable half-hourly rate that tracks wholesale prices — can spike to 30p+ at grid peak hours.
Network & DNO
(6 terms)- Distribution Network Operator (DNO)
- Licensed company responsible for the local electricity distribution network — the cables and substations from National Grid down to your home. UK has 14 DNOs covering geographical regions. The North East is primarily served by Northern Powergrid, with edge cases covered by NGED and SP Energy Networks.
- G98
- ENA Engineering Recommendation G98 — covers generation installations up to 16A per phase (~3.68 kW single-phase). Notification only — the installer notifies the DNO within 28 days of commissioning. No upfront approval required.
- G99
- ENA Engineering Recommendation G99 — covers generation installations above 16A per phase or three-phase. Requires DNO application AND approval BEFORE installation. Typical residential approval time: 11-21 working days. Free for residential under 16 kVA; £400-£2,500 study fees for commercial.
- Meter Point Administration Number (MPAN)
- 13-digit unique identifier for an electricity supply point in the UK. Printed on the top of every electricity bill. Required for all DNO applications, SEG applications, and supplier switches. Distinct from your bill account number (which is supplier-specific).
- Northern Powergrid
- DNO serving most of the North East and Yorkshire. Two licensed sub-areas: Northeast (Northumberland, Tyne & Wear, County Durham, Tees Valley) and Yorkshire. AMP Renewables submits ~95% of G98/G99 applications to Northern Powergrid.
- Data Communications Company (DCC)
- UK organisation that operates the secure smart-meter data network. Receives half-hourly consumption and generation data from SMETS2 smart meters and routes it to electricity suppliers for billing and to SEG suppliers for export payments.
Refrigeration & AC
(5 terms)- Variable Refrigerant Flow (VRF)
- Commercial multi-zone air conditioning system using a single outdoor compressor unit to serve multiple indoor units via refrigerant pipework, with electronically-controlled refrigerant flow per zone. Typical commercial VRF: 5-50 indoor units, 50-300 kW capacity per outdoor unit.
- Variable Refrigerant Volume (VRV)
- Daikin's brand name for VRF systems. Functionally identical to VRF — the technology is the same; Daikin holds the trademark on "VRV" specifically.
- Building Management System (BMS)
- Centralised control system for a commercial building's heating, cooling, ventilation, lighting and access. Modern BMS use protocols like BACnet, Modbus or LonWorks to integrate equipment from different vendors. Most commercial heat pumps and VRV/VRF systems offer BMS integration as standard.
- R32 refrigerant
- Hydrofluorocarbon refrigerant (chemical: difluoromethane). Global Warming Potential 675 (vs older R410A at 2088). Adopted as the UK standard for residential AC and small heat pumps from 2018. Will be replaced by lower-GWP options (R290 propane, R454C) under the F-Gas phase-down.
- R290 refrigerant
- Propane refrigerant. Global Warming Potential 3 (225× lower than R32). Adopted by Vaillant aroTHERM plus heat pumps and some Daikin commercial systems. Flammable (charge limit restrictions in occupied spaces) but the strongest future-proofing against F-Gas phase-down regulations.
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