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Mawson – Houghton-le-Spring Solar Installation (2025)

6kW Solar PV System with Fox ESS Hybrid Inverter & 20.7kWh Battery Storage

Sustainable Energy Engineering Ltd installed a highly efficient 6kW solar PV system with dual Fox ESS EP12 batteries for the Mawson household in Houghton-le-Spring. This setup provides over 20kWh of usable storage, enabling exceptional self-consumption and off-peak charging capability.

The system uses high-performance JA Solar DeepBlue panels paired with the Fox ESS H1-5.0-E-G2 hybrid inverter, delivering strong generation even during lower-light periods. Bird mesh was installed as standard to protect long-term performance.

Technical Information:

Solar Panel Brand & Model:JA Solar DeepBlue 4.0 Pro 500W
Number of Panels:12
Inverter:Fox ESS H1-5.0-E-G2 (5.5kW)
Battery Storage:2 × Fox ESS EP12 (11.52kWh each)
Usable Storage:20.736 kWh
Mounting System:Renusol Roof Mounting Kit
Additional Components:Bird Mesh, AC Isolators, Generation Meter, EP12 Junction Box


Installation Data

Installed Capacity6 kWp
Orientation10°
Inclination30°
Postcode Region9E
Kk Value891
Shade Factor1.00
Estimated Annual Output5,350 kWh
Annual Consumption (Assumed)4,000 kWh
Self-Consumption (PV Only)1,497 kWh
Self-Sufficiency (PV Only)37%
Usable Battery Capacity20.736 kWh
Self-Consumption (PV + Battery)3,528 kWh
Self-Sufficiency (PV + Battery)88%


25-Year Financial Summary

Net Present Value (NPV)£22,804.03
Discounted Payback Period8–9 years
Internal Rate of Return (IRR)14.1%

NPV Explained: Net Present Value measures the long-term financial benefit of solar by discounting future energy savings. A positive NPV means the system pays for itself and produces surplus financial value over its lifetime.

Discounted Payback Explained: Unlike simple payback, this method accounts for inflation and energy price changes, giving a realistic view of when the system becomes profitable.

IRR Explained: The Internal Rate of Return shows the effective annual return on investment. A higher IRR indicates a stronger financial performance compared to traditional investments.



Assumed Values

DC Array Power6 kW
Tilt30°
Azimuth348° (clockwise from South)
System Efficiency87%
AC System Size5.5 kW
Export LimitNo export limit
Annual Electricity Usage4,000 kWh
Utility Rate Inflation5% per annum
Self-Consumption Rate66%
Daily Supply Charge£0.60
Current Electricity Price£0.25
Smart Export Guarantee£0.15
System Lifetime25 years
Inflation Rate2% per annum
Effective Interest Rate2.58% per annum
PV Degradation99% first year, -0.4% annually
Nominal Storage Capacity23.04 kWh
Maximum Depth of Discharge90%
Usable Storage Capacity20.736 kWh
Battery Power11.52 kW
Round Trip Efficiency95%


Project Gallery:

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2,000+ Solar Installs Completed in the North East.

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We've helped homeowners across the North East cut energy bills and reduce carbon emissions with bespoke domestic solar systems, from family homes to larger residential properties. Alongside this, we've delivered projects for schools like Cragside and Dame Dorothy, community hubs such as Kibblesworth Millennium Centre and Alnwick Community Centre, local cafes, churches, and even national brands like Burger King. With major installs for organisations including Darlington College, Phillips Pet Supplies, and Collingwood Healthcare Services, our portfolio shows proven expertise across both domestic and commercial solar - providing tailored installations that deliver long-term savings and sustainability.

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