For a business, electricity is one of the few large costs that feels entirely outside your control. Commercial solar changes that. It turns your roof into a long-term asset that cuts your energy bills, shields you from price rises, and can deliver a return that comfortably beats leaving cash in the bank.
This guide sets out what commercial solar costs in 2026, the returns businesses in Sussex and Kent can realistically expect, and the tax relief you can and cannot claim. It is written by Cre8 Zero, an MCS-certified solar, battery and EV charging installer based in Brighton and serving businesses across the South East.
Why commercial solar makes sense in 2026
The economics have rarely looked stronger. Commercial electricity prices in 2026 sit at roughly 28p to 32p per unit, and every unit your panels generate and you use on site is a unit you no longer buy at that rate.
Businesses are especially well suited to solar because their demand often peaks during daylight hours, exactly when panels generate. A warehouse, factory, office or shop running through the working day can use most of its solar directly, which is where the strongest savings come from.
Key takeaway: the more of your electricity you use during daylight, the faster commercial solar pays back, because you are displacing power you would otherwise buy at full price.
How much do commercial solar panels cost?
Commercial systems are priced by capacity, measured in kilowatts-peak (kWp). Larger systems benefit from economies of scale, so the cost per kWp falls as the system grows. Treat these as indicative 2026 ranges, since roof type, access and components all matter.
- Cost per kWp: roughly £700 to £1,200 per kWp installed
- 30kWp (small commercial roof): roughly £25,000 to £40,000
- 50kWp: roughly £40,000 to £60,000
- 100kWp: roughly £70,000 to £110,000
- 250kWp and above: roughly £150,000 to £250,000 or more
These figures are for supply and installation by an MCS-certified company. A proper site survey is the only way to get an accurate figure, because commercial roofs vary enormously in structure, condition and orientation.
The returns: ROI and payback
This is what most finance directors want to see. For a business with high daytime electricity use, commercial solar typically delivers a return on investment in the region of 10 to 15% a year, with payback often falling between 3 and 7 years.
After payback, the system continues generating largely free electricity for the rest of its 25-year-plus life, which is where the long-term value sits. The exact figures depend on how much of your generation you use on site, your electricity rate and your roof, so treat these as indicative ranges rather than promises.
Key takeaway: businesses that use most of their solar on site often see payback in well under a decade, then decades of low-cost power.
A worked, indicative example
Let us put rough numbers to a realistic case. These are indicative figures to illustrate the principle, not a quote.
Imagine a Kent manufacturer fitting a 100kWp system for around £90,000. On the South Coast, that system might generate in the region of 90,000 units a year. If the business uses 70% of that on site, displacing electricity it would otherwise buy at 30p, that is roughly £18,900 saved each year.
Add export income on the remaining surplus through the Smart Export Guarantee, and the annual benefit rises further. In this example, the system pays for itself in around four to five years, then continues to generate for another two decades. Change the self-consumption rate or the electricity price and the numbers shift, which is why a tailored assessment matters.
Want a model built on your actual load and roof? Book a free energy assessment and our team will run the numbers for your site.
Tax relief: getting it right
Here is where a lot of online advice gets it wrong, so let us be precise. Solar panels are classed by HMRC as a special rate asset, which means they do NOT qualify for full expensing (the 100% first-year deduction that applies to main-pool plant and machinery). Claiming full expensing on solar is a common and costly mistake.
The correct reliefs for most businesses are:
- The Annual Investment Allowance (AIA). This gives 100% tax relief on the first £1m of qualifying capital spend in a year, and solar qualifies. For most SME installations, the AIA covers the entire cost.
- The 50% First-Year Allowance. For companies, spend on special rate assets above the AIA can attract a 50% first-year allowance, with the balance written down at the special rate over time.
- Business rates exemption. Eligible new rooftop solar benefits from a business rates exemption running until 2035, so adding solar should not increase your rateable value during that period.
Tax treatment depends on your business structure and circumstances, so please confirm the specifics with a qualified accountant before making a decision.
Key takeaway: most SME solar installs are fully covered by the Annual Investment Allowance, but solar does not qualify for full expensing, so take proper advice.
Secondary income from the Smart Export Guarantee
Your business does not have to use every unit it generates. Surplus electricity exported to the grid earns income through the Smart Export Guarantee (SEG), which requires larger suppliers to pay for what you export.
For a commercial system, self-consumption is almost always worth more than export, because you avoid buying at 28p to 32p while export rates are lower. Still, the SEG turns any genuine surplus into a secondary income stream rather than a giveaway, and it improves the overall return.
Battery storage for demand management
For many businesses, a battery is the difference between a good system and a great one. Commercial battery storage lets you store daytime solar and use it during peak-price periods, and it can help manage demand charges by smoothing the peaks in your grid draw.
For sites with high early-evening demand, or those exposed to time-of-use commercial tariffs, storage can significantly improve the economics. It also adds resilience, keeping critical operations running through short interruptions. Our team models whether storage stacks up for your specific load profile rather than adding it by default.
No upfront capital? Consider a PPA
Not every business wants to spend capital on solar, and there is a route that requires none. A Power Purchase Agreement (PPA) lets a third party fund, own and install the system on your roof, and you simply buy the electricity it generates at an agreed rate, usually below what you pay the grid.
A PPA means £0 upfront, immediate savings from day one, and the funder taking on maintenance. The trade-off is that you do not own the system, so you forgo the tax relief and the full long-term savings that come with buying outright. For businesses that prefer to preserve capital, though, it is an attractive way to go solar without the initial outlay. We can talk you through both routes so you can weigh ownership against cash flow.
Why choose Cre8 Zero for commercial solar
Commercial installations demand a certified, accountable partner, and that is what we provide. Every Cre8 Zero system is MCS-certified and installed by fully qualified electricians, backed by an insurance-backed workmanship warranty and supported by our 5-star ratings on Trustpilot and Google.
We work with SMEs, manufacturers, warehouses and offices across Sussex, Kent, Surrey, Hampshire and Brighton & Hove, and you can see more about our approach to business installs on our commercial solar page. If you want to talk it through directly, our team is ready when you are via our contact page.
Frequently asked questions
How much do commercial solar panels cost in 2026? Commercial solar costs roughly £700 to £1,200 per kWp installed in 2026, so around £25,000 to £40,000 for a 30kWp system and £70,000 to £110,000 for a 100kWp system. Larger systems cost less per kWp. All figures are indicative and depend on the roof and site.
What is the ROI and payback on commercial solar? For businesses with high daytime electricity use, commercial solar typically delivers a return of around 10 to 15% a year, with payback often between 3 and 7 years. After payback, the system generates largely free electricity for the rest of its 25-year-plus life.
Does commercial solar qualify for full expensing? No. Solar panels are a special rate asset and do not qualify for full expensing. The correct reliefs are the Annual Investment Allowance (100% on the first £1m of qualifying spend) and, for companies, a 50% first-year allowance above that. Always confirm with a qualified accountant.
Is there a business rates exemption for solar? Yes. Eligible new rooftop solar benefits from a business rates exemption running until 2035, so adding solar should not increase your rateable value during that period. Confirm eligibility for your property with a qualified adviser.
What is a solar PPA? A Power Purchase Agreement lets a third party fund, own and install solar on your roof at no upfront cost, and you buy the electricity it generates at an agreed rate, usually below the grid price. You save from day one but do not own the system or claim the tax relief.
Turn your roof into an asset
Commercial solar in 2026 offers South East businesses a rare combination: lower bills, protection from price rises, strong tax relief and a return that beats most alternatives. The first step is a proper look at your roof and your load profile.
Let our MCS-certified team build the numbers for your business. Book a free energy assessment, call us on (020) 3038 4595, or email enquiries@cre8zero.com to start the conversation.
