Farm Solar Glossary UK 2026 | A–Z of Agricultural PV Terms

If you're researching solar for a UK farm in 2026, you'll encounter abbreviations and jargon that fall into six broad areas: grants and tax (FETF, AIA, SFI, CARES, DAERA), finance routes (PPA, Private Wire PPA, asset finance, capital purchase), technical specification (kWp, Tier-1, TOPCon, MCS, NICEIC, G98/G99), planning and regulation (PD, BMV, AONB, LVIA, Class A/J GPDO), operations (O&M, P50, PR, SEG, export limitation), and tenure (FBT, AHA, agrivoltaics).

Below is every term you're likely to meet in a farm solar enquiry, quote or grant application. Each is linked to the relevant pillar page where you can read the practical implications in depth.

A

Agrivoltaics: Dual-use solar — panels installed so the land beneath remains productive for sheep grazing, pollinator wildflower mix, or shade-tolerant crops.
AIA (Annual Investment Allowance): UK tax relief letting farms write off 100% of capital expenditure on plant and machinery (including solar PV) against profits in year one, up to a £1m cap.
AONB (Area of Outstanding Natural Beauty): Protected landscape designation. Roof-mounted solar on existing buildings usually permitted; ground-mounted needs full planning with LVIA.
Asset finance: Finance secured against the installed system and repaid over a fixed term. You own the asset; compare the repayments with the energy the system will save.

B

BESS (Battery Energy Storage System): Battery storage at commercial scale, in modular cabinets or container units. Paired with solar PV it moves daytime surplus into the evening.
Bifacial panels: Solar panels that generate from both front and rear surfaces. The extra yield depends on the mounting height and how much light the ground reflects, so it is larger on ground mounts than on roofs.
BMV land (Best and Most Versatile): Agricultural Land Classification grades 1, 2 and 3a. Planning decisions weigh the loss of BMV land, so poorer grades are easier to consent for ground-mounted solar.

C

CARES (Community and Renewable Energy Scheme): Scottish scheme delivered by Local Energy Scotland for non-profit community groups, not farms — it does not fund farm solar.
Capital allowance: Tax relief on plant and machinery. AIA covers 100% up to £1m a year; solar panels are special-rate plant, so any cost the AIA does not cover goes into the special rate pool at 6% a year.
Class A (GPDO): Permitted development rights for solar on dwellings. Maximum 200mm projection above roof surface.
Class J (GPDO): England's permitted development right for rooftop solar on a farm building (Part 14, GPDO 2015): no capacity limit; no more than 0.2 m proud of a pitched roof; at least 1 m from the roof edge; council prior approval on design and glare above 50 kW; listed buildings excluded.
CO2 saving: Tonnes of carbon dioxide avoided each year by the solar installation, worked out from its output and the carbon intensity of the grid electricity it displaces. Increasingly material for Scope 3 reporting.

D

DAERA (Department of Agriculture, Environment and Rural Affairs): Northern Ireland department. No DAERA scheme pays for solar panels: its Sustainable Farming Investment Scheme (40%, up to £25,000; round 1 closed 3 September 2026) did not list them, the Farm Business Improvement Scheme – Capital closed in 2022 and excluded renewable energy, and there is no DAERA Farm Energy Efficiency Scheme.
DC string: Series-connected group of solar panels feeding one inverter MPPT (Maximum Power Point Tracker) input. String length is set by the panel and inverter voltage limits.
DNO (Distribution Network Operator): The local electricity grid operator. Great Britain has six DNO groups — UK Power Networks, National Grid Electricity Distribution (NGED), SSEN, SP Energy Networks, Northern Powergrid and Electricity North West — and Northern Ireland has NIE Networks. Handles G98/G99 grid connection.

E

EPC (Energy Performance Certificate): Building energy rating, valid for 10 years. On-site solar generation counts towards the rating.
Export limitation: DNO-imposed cap on how much electricity a solar system can export to the grid. Doesn't affect self-consumption.

F

FBT (Farm Business Tenancy): Post-1995 farm tenancy framework under the Agricultural Tenancies Act 1995. Solar on tenanted land needs the landlord's consent under the tenancy terms.
FETF (Farming Equipment and Technology Fund): England-only equipment grant. Its 2026 window closed at midday on 12 May 2026, and its 2023–2026 item lists did not include solar panels to power a farm. England's Improving Farm Productivity (IFP) grant, which paid up to 25% for rooftop solar, closed to full applications on 31 July 2025 with no further round announced.

G

G98 application: DNO connection route for systems up to 16 A per phase (about 3.68 kW single-phase or 11 kW three-phase): install, then notify the network operator.
G99 application: DNO connection application for systems above the G98 threshold (Engineering Recommendation G99). It must be approved before the equipment is ordered or connected.
Ground-mount: Solar panels installed on the ground rather than on a building. Driven post, screw foundation, ballast or elevated agrivoltaic configurations.

H

Half-hourly meter data: 12 months of 30-minute electricity consumption readings. Required for accurate system sizing and self-consumption forecasting.
Heterojunction (HJT): Solar cell technology combining crystalline and amorphous silicon layers, sold as a premium alternative to standard mono-PERC cells.

I

Inverter: Converts DC from solar panels to AC for grid/load use. String, micro, or central architectures. Check the inverter warranty term against the expected life of the system.
IWA-backed warranty: Insurance-backed workmanship warranty: it protects the customer if the installer stops trading before the warranty ends. Check the term and what it covers.

K

kWp (kilowatt-peak): Solar system nameplate capacity at Standard Test Conditions. Typical UK system delivers 850–1,100 kWh per kWp per year.
kWh (kilowatt-hour): Unit of electricity. 1 kWh = 3.6 MJ.

L

LCOE (Levelised Cost of Energy): The lifetime cost of each unit a system produces: capital, running and financing costs divided by its lifetime output.
LiFePO4 (Lithium Iron Phosphate): Battery chemistry that is more thermally stable than NMC and generally lasts more charge cycles. Check the cycle life and retained capacity in the warranty.
LVIA (Landscape and Visual Impact Assessment): Planning study of how a scheme affects the landscape and views, usually asked for with ground-mounted solar, especially in sensitive landscapes (National Landscapes/AONBs, conservation areas, listed settings).

M

MCS (Microgeneration Certification Scheme): Certification for small-scale renewable installations and installers. For the Smart Export Guarantee, suppliers ask for MCS or an equivalent certification on solar up to 50 kW; from 50 kW to 5 MW the installation must be certified and each supplier decides what it accepts.
Microinverter: Single-panel inverter mounted under each module. Suited to partly shaded roofs; higher cost per panel than a string inverter.
MWp (megawatt-peak): 1,000 kWp. In the government's 2025 solar farm cost study (Arup for DESNZ) the typical project was 52 MWp, from 11 to 225 MWp. A UK solar farm needs about six acres per MWp.

N

NICEIC: National Inspection Council for Electrical Installation Contracting. Standard certification for UK commercial electrical contractors.

O

O&M (Operations & Maintenance): Ongoing service contract for solar systems. For solar farms above 5 MW, Arup's 2025 study for DESNZ put O&M at £4,500–£7,600 per MWp a year (2023 prices); small systems are priced individually.

P

PD (Permitted Development): Planning rights that allow specific developments without full planning permission. Most farm rooftop PV qualifies.
PPA (Power Purchase Agreement): Long-term contract where an investor finances and installs solar in exchange for selling you the electricity at an agreed unit rate.
PR (Performance Ratio): A system's actual output divided by its theoretical output for the sunlight it received — a measure of losses, used to check performance year on year.
Private Wire PPA: PPA variant supplying an adjacent commercial user (food processor, glasshouse) under a direct wire rather than via grid export. Higher unit price for the developer.
P50 / P75 / P90: Probability-weighted energy yield forecasts. P50 = 50% probability of exceeding; P90 used for finance underwriting.

R

Roof pitch: Roof angle from horizontal. Optimal UK pitch for solar is 30–40°; flat roofs use 5–15° ballast frames.

S

SEG (Smart Export Guarantee): Larger electricity suppliers must offer at least one export tariff for installations up to 5 MW. Business export rates on suppliers' pages in October 2026 ran from about 3p to 15p per kWh.
Self-consumption %: Proportion of solar generation used on-site rather than exported. It decides the return, because each unit used saves the import price; model it from half-hourly data.
SFI (Sustainable Farming Incentive): England agri-environment scheme. It has no solar items.
SP Energy Networks (SPEN): DNO covering Manweb (Cheshire, Merseyside, North Wales) and SP Distribution (Scotland Central Belt).
SSEN (Scottish & Southern Electricity Networks): DNO covering southern England (Hampshire/Berkshire/Oxfordshire) and most of Scotland north of the Central Belt.
String inverter: Single inverter handling one or more DC strings of panels. A common architecture on farm roofs.

T

Tier-1 panel: BloombergNEF's list of module makers whose panels have been bank-financed on large projects. It is a measure of bankability, not quality, and membership changes over time.
TOPCon: Tunnel Oxide Passivated Contact — an n-type solar cell technology widely used in current panels.
Tracker (single-axis): Ground-mount system that rotates panels east-to-west following the sun. It raises yield per panel but adds capital cost, moving parts and maintenance.
TrustMark: UK Government-endorsed quality scheme for trades working in homes. Some government schemes require a TrustMark-registered business.

U

UKPN (UK Power Networks): DNO covering London, South East England and East of England.

Farm Solar Glossary UK

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