Commercial Solar in Hertfordshire: What Local Businesses Need to Know
A practical guide to commercial solar for Hertfordshire businesses — costs, capital allowances, DNO applications and what to expect.
Commercial Solar in Hertfordshire: What Local Businesses Need to Know
Commercial solar has become one of the strongest financial decisions a Hertfordshire business can make in 2026. With sustained energy prices, capital allowances, and falling installation costs, payback periods of 4-6 years are routine on well-sited commercial properties. Our commercial solar installation service covers the energy data analysis, design, G99 application and installation for Hertfordshire businesses.
Hertfordshire Commercial Solar Pricing
| System Size | Installed Cost | Annual Saving |
| 30kW (small office/retail) | £24,000-£30,000 | £4,500-£5,800 |
| 50kW (warehouse/industrial) | £40,000-£48,000 | £7,500-£9,500 |
| 100kW (large industrial) | £75,000-£90,000 | £15,000-£19,000 |
| 250kW (major facility) | £170,000-£200,000 | £37,500-£47,500 |
Capital Allowances
Solar PV is special rate plant and machinery (HMRC CA22335), so Full Expensing does not apply. The routes that do:
- Annual Investment Allowance (AIA) — 100% first-year deduction on up to £1m of qualifying spend a year, including special rate expenditure (HMRC CA23084)
- 50% first-year allowance — for companies, on new and unused special rate plant
- Special Rate Allowance (6%) — writing-down allowance for expenditure not covered by AIA
For most Hertfordshire businesses, capital allowances reduce the post-tax payback period to 3-5 years.
DNO Applications
Any system above 16A per phase (3.68kW single-phase, about 11kW three-phase) needs a G99 application approved by the DNO before connection; smaller systems are notified under G98 after commissioning. Hertfordshire's DNO is UK Power Networks. Typical timelines:
- G98 notification: within 28 days of commissioning
- G99 application: 8-16 weeks
- G99 with reinforcement: 16-32 weeks
For sites with constrained grid capacity, export limitation can reduce connection complexity significantly.
Battery Storage for Commercial
Commercial battery storage has matured substantially through 2025-26. Key applications:
1. Peak shaving (reducing demand charges)
2. Self-consumption optimisation
3. Backup power for critical loads
4. Grid services revenue
Commercial battery costs run £400-£600 per kWh installed.
Smart Export Guarantee
Commercial installations below 5MW qualify for SEG payments. Best-rate commercial SEG tariffs:
- Rates move constantly and the headline numbers are usually conditional (import-supplier tie-ins, installer tie-ins or battery requirements). As of 30 July 2026 the best no-strings flat rate sits around 15p/kWh, with higher rates available where you also buy your electricity from the same supplier.
- For the current supplier-by-supplier comparison, see our Smart Export Guarantee rates guide, which we re-verify against suppliers' own pages.
Practical Next Steps
For Hertfordshire businesses considering commercial solar, the typical project timeline is 12-20 weeks from initial enquiry to commissioning. We provide free feasibility studies including yield modelling, financial projections and DNO viability assessment. Get in touch.
