Solar PV & Export Details
📊 Solar & SEG Financial Breakdown
Installing rooftop Solar Photovoltaic (PV) panels is one of the most effective ways for UK homeowners to cut grid electricity bills and earn revenue selling excess green power.
Under the statutory Smart Export Guarantee (SEG) scheme, licensed UK energy suppliers pay households for every kilowatt-hour (kWh) of renewable electricity exported back to the national grid. Combined with 0% VAT on solar equipment and labor, typical payback periods have dropped to 7 to 9 years.
⚙️ Statutory Solar PV & SEG Rules for 2026/27
1. The Two Income Streams of Rooftop Solar PV
- Direct Bill Savings (Self-Consumption): Every kWh of solar electricity generated and consumed directly in your home saves ~24.5p per kWh off your standard grid electricity bill.
- SEG Export Revenue: Surplus electricity generated during sunny afternoon hours (which is not used immediately or stored in a home battery) is exported to the grid. Energy suppliers pay between 4.0p and 30.0p per kWh for exported electricity under SEG contracts.
2. Statutory 0% VAT Tax Relief
- Under UK VAT legislation, solar panel installations, inverters, and integrated home battery storage systems carry a 0% VAT rate through March 2027.
- This saves homeowners approximately £1,000 to £1,500 compared to standard 20% VAT rates.
3. Mandatory SEG Eligibility Criteria
To qualify for SEG payments from energy suppliers:
- The installation MUST be certified under the Microgeneration Certification Scheme (MCS).
- The property MUST have an operational smart meter (SMETS2) capable of reading half-hourly export data.
- Peak capacity must not exceed 5kW for single-phase residential properties (or 10kW for three-phase).
📊 Practical Solar Payback Worked Examples
Below are two worked calculation examples illustrating solar payback periods:
- Installation Cost (0% VAT): **£6,500.00**
- Annual Solar Generation: **3,800 kWh / year**
- Self-Consumed Solar (50%): 1,900 kWh × 24.5p = **£465.50 / year Saved**
- Exported Solar (50%): 1,900 kWh × 15.0p = **£285.00 / year SEG Income**
Calculation: Total annual financial benefit = £465.50 + £285.00 = £750.50 per year. Payback period = £6,500 ÷ £750.50 = 8.7 years.
- Installation Cost (Solar + Battery): **£9,500.00**
- Self-Consumed Solar (80%): 3,040 kWh × 24.5p = **£744.80 / year Saved**
- Exported Solar (20%): 760 kWh × 15.0p = **£114.00 / year SEG Income**
Calculation: Total annual benefit = £744.80 + £114.00 = £858.80 per year. Payback period = £9,500 ÷ £858.80 = 11.1 years.
📑 Common Pitfalls & Solar Energy Warnings
- Choosing Low Fixed SEG Tariffs: SEG export rates vary hugely between energy suppliers (from as low as 4p/kWh up to 30p/kWh for premium time-of-use export tariffs like Octopus Outgoing). You are legally free to switch your SEG export contract to a different supplier than your import supplier.
- Unshaded Roof Orientation: South-facing roofs tilted at 30° to 45° achieve 100% generation potential. East/West roofs generate ~80% of peak capacity, whereas North-facing roofs are unviable.
- DNO Grid Connection Approval (G98/G99): Solar systems over 3.68 kW per phase require prior approval from your local Distribution Network Operator (DNO) under Engineering Recommendation G99 before commissioning.
❓ Frequently Asked Questions (FAQ)
The legacy Feed-in Tariff (FIT) closed to new applicants in 2019. SEG replaced FIT, paying generators strictly for exported solar energy measured by a smart meter.
A home battery stores daytime solar energy for use during evening peak hours, boosting self-consumption from 40% to over 80% and offsetting expensive grid electricity.
Rooftop solar panels are classified as **Permitted Development** in England, Scotland, and Wales, provided they do not protrude more than 200mm from the roof slope. Exceptions apply to Listed Buildings and Conservation Areas.
Modern solar panels feature 25-year linear performance warranties (degrading less than 0.5% per year), though solar inverters typically require replacement after 10 to 15 years (£800–£1,200).