Owner-Occupied Commercial Property: Solar for Commercial Property

If you own the building you trade from, you are in the strongest position in commercial solar. Every other asset type on this site has to solve a split incentive — the party who pays for the array is not the party who benefits from the cheaper power. As an owner-occupier you are both parties. There is no lease to engineer, no tenant to negotiate with, no recovery mechanism to design. You fund the system, you consume the generation, you keep the tax relief, and the EPC uplift lands on the asset you already hold. That single fact makes this the simplest and highest-return segment we work in.

Why owner-occupiers have the best economics

The return on a commercial solar array is driven almost entirely by self-consumption — the share of generation you use on site rather than export. Self-consumed power displaces grid electricity at 24–28p/kWh (small-to-medium business rates, ex VAT and CCL, 2026). Exported surplus earns a supplier-set SEG rate of roughly 12–16p/kWh — useful, but barely half the value. The more of your own generation you absorb, the faster the array pays back.

Owner-occupiers absorb the most. You control the load, the operating hours and the roof, so you can size the system to match your daytime demand. Typical self-consumption sits at 50–70% for a single daytime-shift business, rising to 60–80% with a battery and 90–95% for a 24/7 site. Compare that to a landlord on a fully-let building who can only sell power into a tenant arrangement, and the difference in return is structural.

The other advantages stack on top:

• Full first-year tax relief. Solar PV is a special-rate (integral features) asset. Because you are buying it to use in your own trade — not to lease — you claim 100% of the cost in year one through the Annual Investment Allowance (£1m, permanent). A landlord buying solar to lease cannot use the 50% First-Year Allowance and falls back to AIA plus a 6% writing-down allowance. As an owner-occupier the relief is cleaner and faster. See our capital allowances and funding guide for owners for the mechanics.
• Business-rates exemption. Rooftop solar and co-located battery storage are 100% exempt from business rates in England until 31 March 2035 — worth roughly £3,000–£8,000 a year on a 250kW array. Because you occupy under your own name, that saving is unambiguously yours; there is no FRI lease passing it to a tenant.
• Balance-sheet and EPC value. The array is a depreciating-but-revenue-generating asset on your books, and solar typically lifts a commercial EPC by one to three bands (we never promise a specific jump). A better EPC protects you against the MEES floor and supports the building’s value if you ever refinance or sell.

Sizing: 50–300kW for most owner-occupiers

Most owner-occupied commercial buildings — a manufacturing unit, a trade counter, an office HQ, a depot — sit in the 50–300kW band. As a rule of thumb every 1kWp generates around 950 kWh a year, so a 100kW system produces roughly 95,000 kWh annually, and a 300kW system around 285,000 kWh.

We size to your demand, not your roof. A roof big enough for 400kW is no use if your daytime load only absorbs 150kW of it — the surplus exports at SEG rates and dilutes the return. The right starting point is twelve months of half-hourly meter data, which shows your actual daytime baseline and tells us where self-consumption peaks. For sites with a flat midday demand profile, solar alone does the job. For sites that run hard into the evening, or that have spiky loads, a battery earns its place.

A battery of, say, 250kWh paired with a 125kW inverter shifts excess midday generation into the late afternoon and evening, pushing self-consumption from the 50–70% range up towards 80%. Batteries cost £400–£800/kWh, so they are an investment in their own right — we model them on their incremental return, not bundled into the headline payback. Grid-services revenue (frequency response, capacity market) of £6,000–£15,000 a year is possible on a battery of that size, but only where the site contracts a route to market; we never put speculative grid revenue into a standard payback.

Compliance and delivery: the simple path

Owner-occupiers face the lightest regulatory route of any commercial solar buyer.

• Planning. Rooftop commercial solar is permitted development under Class J, following the removal of the old 1MW cap on 21 December 2023 (SI 2023/1279). It is not a free pass — there is a 56-day prior-approval step covering design, appearance and glint/glare — but for the vast majority of buildings it is straightforward. Listed buildings and scheduled monuments are excluded, and an Article 4 Direction can withdraw permitted-development rights in some areas. England only. Car-park canopies fall under Class OA. Our planning and grid guide covers the detail.
• Grid connection. Above roughly 50kW you need a G99 connection agreement from your Distribution Network Operator. This is now the real delivery bottleneck — not planning. We apply early and design around whatever export capacity the DNO will grant, including export limitation where a full connection would stall the project.
• No lease engineering. Because you own and occupy, none of the split-incentive machinery applies. No PPA pricing, no roof lease, no green-lease contribution cap, no service-charge recovery question, no mortgagee or insurer consent tied to granting a third party an interest in your roof. You will still notify your insurer (standard for any roof-mounted plant, and essential if a battery is involved), and a structural roof-loading survey to BS EN 1991 is part of every project. But the ownership layer that complicates every other asset type simply isn’t there.

One thing worth checking early: the age of your roof. If the membrane has fewer than 15 years of life left, it is far cheaper to re-roof and install solar in a single project than to strip and refit the array later. We flag this in the survey so you can align the two works.

A worked example (illustrative)

These figures are illustrative — your numbers depend on your tariff, load profile and roof. Take an owner-occupied 250kW system on a light-industrial unit:

• Capital cost: ~£185,000 ex VAT (commercial installs have been 0% VAT since April 2022).
• Generation: ~237,500 kWh/yr (250kW × 950 kWh/kWp).
• Self-consumption at 65%: ~154,000 kWh used on site, displacing grid power at ~26p/kWh = ~£40,000/yr saved.
• Export of the remaining ~83,500 kWh at an SEG rate of ~14p/kWh = ~£11,700/yr.
• Business-rates exemption: ~£5,000/yr retained.
• Gross annual benefit: roughly £56,700, before tax.
• Tax: the full £185,000 is relieved in year one via AIA, cutting the post-tax cost materially for a profitable company.

On those assumptions the simple payback lands around five years, and the AIA relief pulls the post-tax payback inside that. For a higher-load 24/7 site with self-consumption above 85%, payback can compress to three to five years. Get a site-specific model on our cost page, check what funding applies on the grants and funding page, and when you are ready, request a quote and we will build the numbers off your own meter data.

Common questions

Do owner-occupiers really get a better return than landlords?

Yes, and the gap is structural rather than marginal. A landlord has to route cheaper solar power to a tenant through a PPA or roof lease, which caps how much value they capture and adds legal complexity. As an owner-occupier you consume the generation directly at full grid-displacement value (24–28p/kWh), claim 100% AIA relief because the asset serves your own trade, and keep the business-rates exemption without an FRI lease handing it to anyone else. The same array on the same roof simply pays back faster when you both own and occupy.

How quickly can an owner-occupier array be installed?

For a system above 50kW the critical path is usually the G99 grid connection, not the build. Planning under Class J runs to a 56-day prior-approval window, and the physical install of a 100–300kW rooftop system typically takes two to four weeks once on site. The DNO connection process is the variable — it can range from a few weeks to several months depending on local network capacity — which is why we submit the G99 application at the start, in parallel with planning, rather than waiting.

Should I add a battery from day one?

Only if your load profile justifies it. A battery raises self-consumption and is most valuable on sites that draw power into the evening or have spiky demand the daytime array can’t cover directly. At £400–£800/kWh it is a separate investment with its own payback, so we model it on incremental return rather than folding it into the headline figure. Many owner-occupiers start with solar alone, prove the self-consumption, and add storage once they have a year of real generation data — the inverter and switchgear can be specified to be battery-ready so retrofitting is straightforward.