Commercial Solar Installation Milton Keynes

Overview

Location: Milton Keynes, MK12 6HT
Date of Installation: November 2023
Type: Commercial
Roof Layout: North-East, South-East, and South-West
Panel Count: 154 x JA Solar 405W Mono PERC Half-Cell MBB Black Frame
System Size: 62.37 kWp

System Overview

The solar PV system at 19 Hollin Lane features 154 x JA Solar 405W Mono PERC Half-Cell MBB Black Frame panels, with a total system size of 62.37 kWp. It includes a Solis 50 kW S5 3-Phase inverter with 5 MPPTs, an Emlite Bi-Directional Generation Meter, a G99 Mains Relay, and a Fireman’s Safety Switch for added safety. The system will generate approximately 53,096 kWh per year and is mounted using Sunfixings – Mounting Rail Direct on a roof layout spanning North-East, South-East, and South-West orientations, ensuring optimal energy generation for the commercial property.

Performance Estimates

Annual Energy Generation

PV – 26 x 405W

• Proposed System Rating (kWp): 10.53 kWp

• Postcode Region: Region 1

• Array Orientation: 80°

• Pitch of Mount: 5°

• Over Shading Factor: Factor 1.0

• Estimated Solar Radiation: 833 kWh/Annum

• Estimated Annual System Output Using MCS Standard Procedure: 8,771 kWh/Annum

PV – 102 x 405W

• Proposed System Rating (kWp): 41.31 kWp

• Postcode Region: Region 1

• Array Orientation: 10°

• Pitch of Mount: 5°

• Over Shading Factor: Factor 1.0

• Estimated Solar Radiation: 864 kWh/Annum

• Estimated Annual System Output Using MCS Standard Procedure: 35,691 kWh/Annum

PV – 26 x 405W

• Proposed System Rating (kWp): 10.53 kWp

• Postcode Region: Region 1

• Array Orientation: 100°

• Pitch of Mount: 5°

• Over Shading Factor: Factor 1.0

• Estimated Solar Radiation: 820 kWh/Annum

• Estimated Annual System Output Using MCS Standard Procedure: 8,634 kWh/Annum

Total System Size and Output

• Total System Size: 62.37 kWp

• Total Estimated Annual Output approximately: 53,096 kWh/Annum

Consumption & Grid Export

An energy consumption analysis was conducted based on an average household usage of 2,948 kWh per year. The expected distribution of generated electricity was:

• Self-consumed directly from solar:

• Stored and used via battery:

• Exported to the grid:

• Losses:

Smart Export Guarantee (SEG) Eligibility

The installation qualified for SEG payments, allowing excess electricity exported to the grid to be sold back to an electricity supplier. More information on SEG eligibility and applications can be found at Ofgem.

Environmental Impact

The system contributed significantly to reducing the property’s carbon footprint:

• Annual CO₂ savings: 21.3 tonnes

• Equivalent to:

  • 50,000 miles driven by a diesel car

  • CO₂ absorption of approximately 1,200 mature trees annually

Disclaimer: These calculations are based on estimated system output and standard carbon emission factors provided in the UK Government’s Greenhouse Gas Reporting: Conversion Factors 2024. Actual results may vary due to differences in household energy use, weather conditions, and grid carbon intensity.

Performance and Financial Projections

Investment & Expected Savings

The total cost of the installed system was £44,350.00 (including VAT at 0%). Based on an average electricity price of 28p per kWh, the estimated first-year savings from the system are approximately £14,853.88 (53,096 kWh x £0.28).

The estimated payback period for this system is three years, with ongoing savings throughout its lifespan.

Disclaimer: Payback periods are estimated based on current electricity prices and SEG rates. Future price changes, electricity consumption habits, and system performance may affect the actual payback timeline.

Frequently Asked Questions

How does shading affect this system?

Since the system is installed on roofs with North-East, South-East, and South-West orientations and there is no shading, the system will perform at its optimal efficiency throughout the day. The panels will receive maximum sunlight exposure during different parts of the day, with the South-East and South-West-facing panels capturing energy in the morning and late afternoon, while the North-East-facing panels will generate power during midday. With no shading to any part of the system, you can expect consistent and reliable electricity generation, ensuring minimal performance loss due to shading.

Usually, we would not install panels facing north; however, the North-East-facing panels were installed due to the low-degree pitch of the roof. They will still generate electricity, but their performance may be slightly lower compared to the South-East and South-West panels. This is because the North-East orientation typically receives less sunlight, especially in the morning.

What is the expected performance over its lifetime?

The JA Solar 405W Mono PERC Half-Cell panels typically experience a 0.5% degradation in performance per year. This means the panels will gradually lose efficiency as they age, but they will still generate a significant amount of electricity throughout their 30-year lifespan.

Performance Breakdown Over 30 Years:

• Year 1: 100% output → 53,096 kWh

• Year 10: ~95% output → 50,441 kWh

• Year 20: ~90% output → 47,787 kWh

• Year 30: ~85% output → 45,133 kWh

  
  

• Total Energy Generation Over 30 Years:
  By the end of the 30-year period, the system is expected to generate approximately 1,450,000 kWh of electricity, taking into account degradation and average annual output.

Can excess electricity be sold back to the grid?

While it is possible to sell excess electricity back to the grid, the large electricity consumption of the business means that most of the solar energy generated will be used instantly to meet on-site demand. On sunny weekends, some excess electricity may be exported, but this will likely be minimal due to the system’s capacity being used primarily during business hours.

Since the export rate for businesses is typically 3-5p per kWh, it is far more economical to use the electricity on-site or store it in a battery storage system. This strategy maximises savings by reducing reliance on grid electricity, particularly during high-cost periods such as evenings or when solar generation is low.

Installation

The system was installed by a trained installation team certified by MCS, RECC, and NAPIT and was completed within a short period with minimal disruption to the household.