Project Overview
Shannon Thomas lives in a 4-bed home in Redruth, Cornwall, with her Husband and 3 children and have a separate extension used as a home office. Working from home means electricity usage is consistent throughout the day, making solar and battery storage an ideal solution.
In May 2025, ES Holdings Group Ltd installed a 12 kW solar PV system paired with 11.5 kWh of battery storage to help Shannon reduce energy bills, cut carbon emissions, and export surplus energy back to the grid at 15p per kWh.
System Details
- 24 × Aiko Neostar 2S+ 500W Dual Glass All Black Panels (12.0 kWp total)
- Fox ESS KH 10kW Hybrid Inverter
- Fox ESS 11.5 kWh Battery Storage (1 × Master, 3 × Slave modules)
- Mounting: Fastensol pitched roof mounting system
- Monitoring: Real-time smart app with live tracking of solar, battery, and grid flows
📌 The inverter and batteries were fitted into the loft space for a neat, out-of-the-way installation. To make this possible, the system used one master unit and three smaller slave batteries, which were easier to handle and provided the required storage capacity while maintaining accessibility.
Energy Performance
Projected Performance (from proposal)
- Annual PV Generation: 9,939 kWh
- Annual Household Consumption: 5,818 kWh
- Self-consumed solar (with battery): 4,445 kWh
- Exported to grid: 5,316 kWh
- Grid import reduced to: 1,373 kWh (76% grid independence)
These projections were based on industry-standard modelling, shading analysis, and assumptions about household usage.
Real Performance Data (May – July 2025)
After just three months, the system is already outperforming the initial projections.
May 2025
- PV Generation: 1.04 MWh (1,040 kWh)
- Exported to Grid: 695.9 kWh
- Self-Consumption: 344.1 kWh
- Household Load: 327.4 kWh
- Grid Import: 3.6 kWh
- Self-Sufficiency: 99%
June 2025
- PV Generation: 1.62 MWh (1,620 kWh)
- Exported to Grid: 1.02 MWh (1,020 kWh)
- Self-Consumption: 600.0 kWh
- Household Load: 588.2 kWh
- Grid Import: 6.6 kWh
- Self-Sufficiency: 99%
July 2025
- PV Generation: 1.63 MWh (1,630 kWh)
- Exported to Grid: 1.04 MWh (1,040 kWh)
- Self-Consumption: 590.0 kWh
- Household Load: 567.4 kWh
- Grid Import: 7.9 kWh
- Self-Sufficiency: 99%
📊 Across these three months, Shannon’s home required ~1,483 kWh, of which 99% was supplied by solar & battery. Only ~18 kWh came from the grid.
Actual Export Income (May – July 2025)
On top of her savings, Shannon has already earned £413.39 from selling surplus energy back to the grid at 15p/kWh:
- May: £104.38
- June: £153.00
- July: £156.00
This income is additional to the savings on her bill, showing how well the system is performing.
Ongoing Monitoring
We will be updating this case study with fresh data every 3 months. This will allow us to track the system’s performance through different seasons — including winter — and demonstrate how it performs across a full year.
Financial Benefits
- Annual Bill Before Solar: ~£1,357
- Projected Bill After Solar: ~£320
- Export Income (first 3 months actual): £413.39
- Expected Export Income (annual): ~£797
- Total First Year Benefit (projection): ~£1,835
- Payback Period: ~5 years
- System Cost: £9,023.50 (inc. VAT)
With actual performance running ahead of projections, Shannon is on course to achieve even greater savings and export income.
Environmental Impact
- Annual CO₂ Savings (projection): 2,058 kg
- Equivalent to:
- Driving 7,350 fewer miles in a diesel car
- Planting 94 trees each year
