Commercial Solar

Commercial Solar Panels UK 2026: A Practical Business Guide

Published by AFTA Electrical · May 2026 · Commercial Solar

Commercial solar is one of the most reliable capital investments a business can make in 2026. The combination of significant energy cost savings, potential SEG income, and a system lifespan of 25+ years means most commercial installations pay back in 4–8 years. What follows is a practical guide for business owners and facilities managers considering their first commercial installation.

Commercial Solar System Sizes and Costs

System SizeAnnual GenerationBest ForInstalled Cost (approx)
10–20kW9,000–18,000 kWhSmall commercial, farm buildings£15,000–£30,000
20–50kW18,000–45,000 kWhMid-size commercial, warehouses£30,000–£60,000
50–100kW45,000–90,000 kWhLarge warehouses, industrial units£60,000–£110,000
100kW+90,000+ kWhLarge commercial, multi-sitePOA

Commercial solar carries 20% VAT (unlike domestic, where 0% applies). However, most businesses can reclaim input VAT through their VAT return.

Commercial Solar ROI

For a business paying 28p/kWh for electricity and generating 30,000 kWh/year from a commercial system, the direct saving is approximately £8,400/year. Add SEG income of £1,500–£3,000/year (depending on tariff and export volume), and payback on a £40,000 system is around 4–5 years. After that, 20+ years of near-free electricity.

Planning Permission for Commercial Solar

Rooftop commercial solar on existing buildings is generally permitted development (no planning required) up to certain thresholds. Ground-mounted commercial solar almost always requires full planning permission. Listed buildings and conservation areas require prior approval. We advise on planning requirements during the initial survey.

What Makes a Good Commercial Solar Installer

Capital Allowances: Commercial solar installations are eligible for capital allowances, allowing businesses to offset the cost against taxable profit. Consult your accountant regarding the Annual Investment Allowance (AIA) and Full Expensing rules.

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Frequently Asked Questions

A 20kW commercial system costs approximately £30,000–£40,000 installed. Larger 50–100kW systems run £60,000–£110,000. Commercial solar carries 20% VAT, which most VAT-registered businesses can reclaim.

Most well-specified commercial systems pay back in 4–8 years, with a system lifespan of 25+ years. The exact figure depends on your current electricity tariff, roof orientation, and self-consumption percentage.

Rooftop installations on existing buildings are usually permitted development. Ground-mounted systems and listed buildings almost always need planning permission. We advise on this during survey.

G99 is the application process for connecting generating systems above 16A/phase to the grid. Most commercial solar systems above 11kW require a G99 application to the DNO (Distribution Network Operator). This can take 8–20 weeks, so factor it into your project timeline.

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