Solar PV & Battery Storage Case Studies
Real renewable energy projects designed and installed by Green Energy Systems across Hampshire, Berkshire, Surrey, Wiltshire and the surrounding areas.
Every property is different. These case studies show how carefully designed solar PV, battery storage and energy management systems can reduce grid electricity use, improve energy independence and deliver long-term financial savings.
Our case studies include system design details, annual electricity consumption, installed equipment, performance results and expected return on investment.
High-Consumption Home Solar, Battery & Energy Management Case Study
8.55 kWp Solar PV | 30 kWh Battery Storage | Cascaded Huawei Inverters | Smart EV Charging
Green Energy Systems designed a high-capacity solar PV and battery storage system for a large domestic property in North Hampshire with significant year-round electricity demand.
The property includes a heated swimming pool, sauna, steam room, electric Aga and EV charging, creating a complex load profile that required more than a standard solar installation.
The system was designed to maximise solar self-consumption, store excess generation for later use and take advantage of lower-cost overnight electricity during winter.
Annual electricity use: 13 MWh
Solar PV array: 9 kWp
Battery Storage: 30 KWh
Inverter: 2x4KW single phase cascaded inverters
Major loads: Heated pool, sauna, steam room, electric Aga and EV charging
Operating strategy: Solar charging in summer and overnight tariff charging in winter
Estimated result: Significant reduction in peak-rate grid electricity use
Installed by Green Energy Systems Ltd — MCS certified, RECC member and fully insured.
Project Overview
Green Energy Systems designed and installed a new 8.55 kWp solar PV and 30 kWh battery storage system for a large main residence in North Hampshire.
The property consumed approximately 13,000 kWh of electricity each year and already had a separate 3.68 kW legacy Feed-in Tariff system. The new installation was designed to operate independently, preserving the existing FIT arrangement while substantially reducing annual electricity costs.
Annual Consumption
13,235
kWh per year
Solar PV Array
8.55 KWp
EV Charging
Zappi EV Charger
Result
43% reduction in grid electricity use
Tariff Strategy
Switch to Octopus Intelligent Go
Increase Power
2 × 4 kW Huawei SUN2000 Cascaded
Battery Storage
30 KWh
DNO Export Limit
6KW
The Challenge
The property had a high and strongly seasonal electricity demand.
During winter, the electric Aga created a substantial continuous load. During summer, the heated swimming pool became one of the main consumers of electricity, particularly after the customer installed a pool heat pump.
The customer also owned an electric vehicle but was not using a time-of-use electricity tariff. This meant that electricity used overnight, including EV charging and battery charging, was being purchased at standard daytime rates.
A further design constraint was the existing 3.68 kW FIT system. This had to remain electrically separate so that the original generation metering and tariff arrangement were not disturbed.
The clay pantile roof also presented a practical installation challenge because the tiles were brittle and required careful handling, suitable mounting hardware and additional attention during installation.
The Solution
Green Energy Systems installed a separate 8.55 kWp solar PV system using 19 high-output 450 W modules.
The array was connected to two cascaded 4 kW Huawei SUN2000 inverters, providing 8 kW of combined inverter capacity. The cascaded arrangement also allowed the 30 kWh battery system to operate as a coordinated installation and provided flexibility for future storage expansion.
The existing 3.68 kW FIT installation was left completely separate, preserving the original generation meter and tariff eligibility.
A gateway was included to provide backup power to selected essential circuits during a grid outage.
The customer was also moved to Octopus Intelligent Go, giving access to six hours of overnight electricity at approximately 5p/kWh compared with approximately 25 p/kWh during peak periods.
The operating strategy was designed around the property’s seasonal loads:
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In summer, solar generation supplies the house, pool equipment and pool heat pump while charging the battery.
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In winter, the battery charges during the low-cost overnight tariff and discharges during peak-rate periods to support the Aga and normal household demand.
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The Zappi charger provides smart EV charging and access to the Intelligent Go tariff.
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Export is limited to 6 kW in accordance with the agreed network constraint.
Results
The new 8.55 kWp array is projected to generate approximately 7,054 kWh of renewable electricity each year.
Combined with the 30 kWh battery, time-of-use tariff and load-management strategy, the system is expected to reduce annual electricity bills by approximately 43%.
During favourable summer conditions, the customer’s daily electricity cost reduced from approximately £6 to as little as 4 pence on some days.
The system allows a much greater proportion of the property’s electricity demand to be met by:
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Solar generation during the day
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Stored solar energy during the evening
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Low-cost overnight electricity during winter
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Smart EV charging during the off-peak tariff window
The total project investment was £26,292, with an estimated payback period of approximately seven years.
New Solar PV Array
8.55 kWp
Battery Storage
30 kWh
Projected Annual Generation
7,054 kWh
Projected Annual Bill Reduction
43% reduction
Export Limitation
6 kWh
Estimated Payback
Approximately 7 years