Direct Answer: Is Solar Worth It for UK Factories?
The Bottom Line
For most UK factories with over £80,000 annual electricity costs, solar panels are worth it in 2026. At current electricity rates of 28–32p/kWh, a well-designed factory solar system delivers a 3–5 year payback and 20+ year financial return. The investment is most compelling for energy-intensive operations: food manufacturing, cold storage, automotive, plastics, and chemical processing. It is less compelling for operations with primarily night-time electricity demand or those in short-lease premises.
When Solar IS Worth It for Your Factory
The following five scenarios represent cases where factory solar typically delivers a strong and clear return on investment. The more of these criteria your facility meets, the stronger the business case.
1. You Spend Over £80,000 Per Year on Electricity
At £80,000+ annual electricity spend, there is enough saving potential to deliver a compelling payback. A system that offsets 40% of consumption saves £32,000/year. At a system cost of £100,000–£150,000, that is a 3–5 year payback. Below £80,000/year electricity spend, paybacks can stretch to 5–7 years — still reasonable, but less clear-cut.
2. Your Operations Run Primarily During Daylight Hours
Solar is most effective when generation and consumption align. A factory operating Monday–Friday, 7am–6pm can self-consume 70–85% of solar generation. A 24/7 operation self-consumes only 35–50% without battery storage. High self-consumption means more electricity is valued at the full grid rate (28–32p/kWh) rather than being exported at SEG rates (3–6p/kWh).
3. You Have a Suitable Roof with 500m²+ of Usable Space
Most industrial buildings have large, relatively unobstructed flat roofs that are ideal for solar installation. A 500m² usable roof supports approximately 50kW of solar, generating around 47,500 kWh/year. Most factories can accommodate far more than this. If your roof is in good structural condition, has adequate load-bearing capacity, and is free of obstructions, it is likely a strong candidate.
4. You Face ESOS, Net Zero or Customer ESG Requirements
Energy-intensive businesses qualifying under the Energy Savings Opportunity Scheme (ESOS) Phase 4 must identify energy saving measures — solar panels clearly satisfy this requirement and generate Scope 2 emissions savings. Supply chain customers (particularly in automotive, retail and food) are increasingly requiring Scope 3 emissions data from suppliers. Solar provides verifiable, auditable renewable energy consumption that satisfies many of these requirements.
5. You Own the Building or Have a Long Lease (15+ Years)
Solar panels have a technical lifespan of 25–30 years and a warranty period of 25 years on generation performance. To fully realise the financial return, you need to be in the building long enough to benefit. Building owners gain 100% of the return. Long leaseholders can negotiate solar rights into their lease and benefit similarly. Short leases below 10 years make the investment significantly less attractive.
When Solar May NOT Be Worth It (Yet)
An honest solar specialist will tell you if your situation is not currently well-suited to solar. Here are the genuine reasons to pause.
| Situation | Why It Reduces the Case | Potential Solutions |
|---|---|---|
| All-night operations, minimal daytime use | Low self-consumption means most generation is exported at low SEG rates; payback extends to 8–12 years | Battery storage can shift solar generation to night use; model with and without storage |
| Lease under 10 years remaining | Cannot recoup investment; risk of losing asset on lease expiry | Negotiate lease extension first; discuss with landlord about shared investment |
| Roof requiring significant repairs first | Adds £10,000–£80,000 to effective project cost; reduces ROI | Combine roof replacement with solar installation; some installers can coordinate this |
| Electricity spend under £30,000/year | System size likely too small for compelling economics; paybacks of 6–10 years common | Still worth getting a quote; EPC and ESG benefits may justify smaller system |
| Conservation area or listed building | Planning permission likely required; may be refused; adds cost and uncertainty | Check with local planning authority first; some panels (in-roof, or on non-visible elevations) may be acceptable |
25-Year Financial Model: 300kW System Example
The following model illustrates the financial return for a 300kW rooftop solar system on a medium-sized UK factory. Assumptions are conservative and based on 2026 market conditions.
Model Assumptions
- System size: 300kW
- Installation cost: £220,000 (ex-VAT)
- Annual generation: 285,000 kWh/yr
- Self-consumption rate: 80% (228,000 kWh)
- Export rate: 20% (57,000 kWh)
- Electricity buy price: 30p/kWh (2026)
- SEG export rate: 5p/kWh
- Annual electricity price inflation: 3%
- Panel degradation: 0.5%/year
- Annual O&M cost: £3,500/year
| Year | Grid Rate (p/kWh) | Annual Saving + Export | Net Annual Benefit | Cumulative Net |
|---|---|---|---|---|
| Year 1 | 30.0p | £71,250 | £67,750 | -£152,250 |
| Year 2 | 30.9p | £73,345 | £69,845 | -£82,405 |
| Year 3 | 31.8p | £75,483 | £71,983 | -£10,422 |
| Year 4 | 32.8p | £77,724 | £74,224 | +£63,802 (PAYBACK) |
| Year 5 | 33.8p | £79,961 | £76,461 | +£140,263 |
| Year 10 | 38.8p | £91,427 | £87,927 | +£563,000 |
| Year 15 | 44.5p | £103,800 | £100,300 | +£1,050,000 |
| Year 20 | 51.1p | £117,200 | £113,700 | +£1,640,000 |
| Year 25 | 58.7p | £131,800 | £128,300 | +£2,300,000 |
Model notes: Annual saving includes self-consumption value plus SEG export income minus O&M costs. Electricity price inflated at 3%/year. Panel output degraded at 0.5%/year. Year 13 inverter replacement cost of £15,000 included. NPV at 8% discount rate: approximately £480,000 on a £220,000 investment.
Key Financial Finding
A 300kW factory solar system costing £220,000 reaches payback in under 4 years and generates net cumulative returns of approximately £2.3 million over 25 years — a return of over 10:1 on the original investment, without any government grants. With AIA tax relief reducing the effective cost to approximately £165,000, the return on effective capital deployed is even stronger.
What Could Go Wrong? Honest Risk Assessment
No investment is without risk. Here is an honest assessment of the things that can reduce the return from factory solar.
Inverter Failure
Moderate RiskString inverters have a typical working life of 10–15 years. Replacing inverters at year 12–15 costs £8,000–£20,000 depending on system size. This is a manageable, predictable cost that is easily incorporated into financial modelling. Ensure your installer provides a minimum 10-year warranty on inverters, and preferably 12–15 years.
Roof Leak After Installation
Low Risk (if managed)For ballasted flat-roof systems, panels are not fixed to the roof and carry minimal leak risk. For penetrating systems (pitched roofs), poor workmanship can cause leaks. Ensure your contract includes a clear statement of liability for any post-installation roof damage, and that the installer carries appropriate professional indemnity and public liability insurance.
Lower-Than-Forecast Generation
Low RiskUK solar generation is predictable within a ±10% range year on year. The most common cause of underperformance is shading from obstacles not properly surveyed at design stage. Request a generation P50 and P90 estimate from your installer — P50 is the likely output in a typical year; P90 is the output likely to be exceeded in 90% of years.
You Sell or Vacate the Building
Low RiskSolar panels add value to a freehold commercial building — a building with a generating asset and improved EPC rating commands a higher sale price. If you sell with solar in place, you will recover a portion of the remaining system value in the sale price. If you are a leaseholder, ensure your lease agreement addresses what happens to the solar installation on vacating.
Electricity Prices Fall Significantly
Moderate RiskIf UK electricity prices fell back to pre-2021 levels of 12–15p/kWh, the saving per kWh generated would halve. Payback periods would extend to 6–10 years. The financial model would still be positive over 25 years, but less compelling. However, most energy analysts do not forecast a return to pre-2021 prices due to structural network cost increases and the UK ETS carbon price.
Solar vs Other Energy Investments
It is worth comparing solar against other common factory energy investments to understand where it sits in the priority order.
| Investment | Typical Payback | Typical Annual Saving | Relationship to Solar |
|---|---|---|---|
| LED lighting upgrade | 1–3 years | £5,000–£30,000 | Do first — reduces base demand, improves solar economics |
| Compressed air efficiency | 1–4 years | £3,000–£25,000 | Do first — reduces base demand |
| Rooftop solar PV | 3–5 years | £30,000–£250,000+ | Flagship investment after efficiency measures |
| Battery storage (standalone) | 6–10 years | £8,000–£40,000 | Complementary to solar; improves solar value for 24/7 operations |
| Building insulation | 4–8 years | £5,000–£30,000 | Complementary; reduces gas heating cost (different energy source) |
| Heat pump (gas boiler replacement) | 5–10 years | £10,000–£60,000 | Solar + heat pump: increases electricity demand for solar to offset |
The general priority should be: (1) implement no-cost and low-cost energy efficiency measures first, (2) invest in LED and compressed air improvements, then (3) install solar to offset the remaining reduced electricity demand. Solar installed after efficiency improvements is sized on a lower base consumption — meaning less capital is deployed for the same offset percentage.
Hidden Benefits That Improve the Business Case
The financial model above focuses only on electricity savings and SEG export income. The full business case for factory solar includes several additional benefits that are harder to quantify but genuinely material.
ESG Reporting and Scoring
Solar generation provides verifiable Scope 2 emissions reductions. For businesses reporting under TCFD, SECR, or customer ESG questionnaires, this has direct commercial value — particularly for suppliers to large corporates with published Net Zero targets.
Net Zero Compliance (Scope 2)
Solar reduces your Scope 2 greenhouse gas emissions (purchased electricity). For businesses with internal or externally-reported Net Zero targets, this is a meaningful contribution to decarbonisation strategy with lower cost than many alternative approaches.
Energy Price Volatility Protection
Solar generation has a known, fixed cost per kWh (the capital cost amortised over the panel life). Once installed, your cost of solar-generated electricity is essentially zero. This provides a genuine hedge against energy price spikes — something the 2021–2023 energy crisis demonstrated is a material business risk.
EPC Rating Improvement
Solar panels improve the EPC rating of a commercial building. With the government's Minimum Energy Efficiency Standards (MEES) requiring EPC Band C for new commercial leases from April 2027, this is increasingly a legal compliance issue as well as a commercial one. Better EPC ratings support higher property valuations.
ESOS Phase 4 Compliance Support
The Energy Savings Opportunity Scheme (ESOS) Phase 4 compliance deadline is December 2027. Installing solar satisfies the requirement to identify and implement energy saving measures. Companies that have already invested in solar can point to it as evidence of action — reducing compliance burden and associated professional fees.
Supply Chain Retention
Major manufacturers in automotive, retail and food are increasingly requiring Tier 1 suppliers to demonstrate Scope 1 and 2 emissions reductions as a condition of contract renewal. Solar panels provide a clear, auditable reduction in purchased electricity emissions that satisfies many such requirements.