Manufacturing solar glossary

kWp (kilowatt-peak)

The rated output of a solar array under standard test conditions. Manufacturing systems are sized in kWp, typically 50 kW to 2 MW. As a guide, one kWp needs about five to six square metres of roof and generates 900 to 1,000 kWh a year in the UK.

Self-consumption

The share of your solar generation used on site rather than exported. Self-consumed power replaces grid electricity at your full import rate, so a high daytime or shift-based load means a shorter payback. It is the single biggest driver of return for a manufacturer.

G99

The Engineering Recommendation governing how generation above 17 kW per phase connects to the grid. A G99 application to your Distribution Network Operator is required for essentially every manufacturing array, and connection dates commonly run 6 to 18 months on constrained networks.

DNO (Distribution Network Operator)

The company that owns and operates the local electricity distribution network (for example National Grid Electricity Distribution, Northern Powergrid, UK Power Networks). Your DNO approves the G99 connection and sets any reinforcement cost.

SEG (Smart Export Guarantee)

The scheme under which licensed suppliers pay for surplus solar you export to the grid, typically 4 to 15p per kWh. Export is the secondary value stream; self-consumption at your full import rate is worth far more.

PPA (Power Purchase Agreement)

A financing route where a funder owns and operates the solar system on your roof and you buy the power it generates at a fixed rate below your grid tariff, with zero capital outlay and off-balance-sheet treatment.

Asset finance

A financing route where you own the system, funded over 7 to 15 years. Payments are higher per kWh than a PPA but you keep all the savings and own the asset, and most projects are EBITDA-positive from year one.

AIA (Annual Investment Allowance)

A capital allowance that lets a profitable company deduct 100% of the first £1m of qualifying plant and machinery, which includes solar PV, from taxable profit in year one, giving up to roughly 25% effective tax relief.

IETF (Industrial Energy Transformation Fund)

A UK government fund providing grants for energy efficiency and deep decarbonisation at eligible industrial sites, usually at a 30 to 50% intervention rate through periodic competition windows.

CCA (Climate Change Agreement)

A voluntary agreement for energy-intensive sectors that gives a Climate Change Levy discount in exchange for energy-efficiency commitments. On-site solar reduces metered grid consumption and improves CCA performance.

Scope 2 emissions

The indirect greenhouse-gas emissions from the electricity a site buys. Self-consumed solar directly cuts market-based and location-based Scope 2, which feeds CDP, SBTi and EcoVadis submissions and passes customer supply-chain audits.

Half-hourly meter data

A full year of your electricity use recorded every 30 minutes. We model every system from this data, shift by shift, so the specified size reflects how the plant actually draws power rather than an annual average.

LCOE (levelised cost of electricity)

The lifetime cost of generating a unit of solar electricity, typically 4 to 7p per kWh for a manufacturing PV system against 22 to 32p per kWh grid retail. It is the fairest way to compare solar with grid supply.

DUoS (Distribution Use of System) charges

Network charges for using the local distribution network, higher during red-band peak periods. Heavy peak-time demand can make battery storage economic alongside solar for a manufacturer.

MCS (Microgeneration Certification Scheme)

The certification that underpins SEG eligibility and signals a quality-assured install. Commercial MCS certification is a baseline requirement for a credible manufacturing solar installer.

Ballasted vs rail-fixed mounting

Two ways to fix panels: ballasted systems sit on weighted trays on a flat roof with no penetrations, while rail-fixed systems clamp or bolt to a pitched metal roof. The right choice depends on roof type, structure and warranty.

Self-consumption ratio

The proportion of annual generation used on site. A daytime-heavy or 24/7 manufacturing load can push this to 80 to 95%, which is what gives the sector its strong solar economics.

SPF1981

The fire-safety design standard for rooftop solar PV, increasingly an insurer requirement. We design to it as standard, which many UK installs still overlook.

Want the numbers behind these terms for your own site? See the cost guide, the grants and funding page, or read our manufacturing solar guides.