West Bletchley Rail Depot Solar PV Installation
This solar PV installation at West Bletchley Rail Depot features a 153.00 kW ground-mounted system, designed to optimise energy efficiency and reduce reliance on the grid. Generating approximately 128,920 kWh annually, the system makes a significant contribution to sustainability efforts. The project delivers substantial energy savings and long-term operational benefits for the rail depot.
Feb 10, 2025
340
153
kW
Overview
Location: Bletchley Railway Depot
Date of Installation: February 2025
Type: Commercial
Mounting Type: Ground-mounted, 30-degree orientation
Panel Count: 340 × Trina Vertex S TSM-450W NEG9R.28
System Size: 153 kWp

System Overview
The installation comprises 340 × Trina Vertex S 450W solar panels, paired with two Solis 60kW 5G three-phase inverters. The panels are mounted on a Fastenol ballasted ground-mounted tray system, with each panel requiring 36 kg of ballast. The project includes full electrical work, commissioning, certification, and notifications.
Performance Estimates
Annual Energy Generation, Consumption & Grid Export
System Capacity: 153.00 kWp
Array Orientation: 30°
Panel Inclination: 10°
Estimated Annual System Output: 128,920 kWh
The solar PV system is expected to generate approximately 128,920 kWh of electrical energy per year.
Due to the high anticipated on-site electrical demand, only a small amount of energy is expected to be exported back to the grid. Nevertheless, the solar PV system will be eligible for the Smart Export Guarantee (SEG), allowing any excess electricity exported to the grid to be sold back to an electricity supplier. More information on SEG eligibility and applications can be found on Ofgem's website.
Environmental Impact
The system contributes significantly to reducing the property's carbon footprint:
Annual CO₂ savings: 26 tonnes
Equivalent to:
67,000 miles driven by a diesel car (400g CO₂ per mile)
CO₂ absorption of approximately 1,322 – 3,061 mature trees annually (22kg CO₂ per tree per year)
Disclaimer: These calculations are based on estimated system output and standard carbon emission factors from the UK Government’s Greenhouse Gas Reporting: Conversion Factors 2024. Actual results may vary due to energy usage, weather conditions, and grid carbon intensity.
Performance and Financial Projections
Investment & Expected Savings
The total cost of the installed system was £88,950.00 (ex. VAT). Based on the system’s annual generation of 128,920 kWh and the current electricity price of 28p per kWh, the estimated first-year savings are approximately £36,000.
The estimated payback period for the system is 3 years, with the system continuing to deliver substantial energy savings over its 30-year 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.
Live Monitoring and Updates
The installed system is monitored by Chiltern Solar via the SolisCloud App, which provides:
Graphical display of power flow
String-by-string monitoring
System alarms and notifications
Frequently Asked Questions
How does shading affect this system?
The system has an overshading factor of 0.95, meaning minor shading may slightly reduce efficiency but is not a significant concern.
What is the expected performance over its lifetime?
Estimated 887 kWh/kWp of solar radiation per year, with an annual output of 128,920 kWh.
While degradation over time is not explicitly stated, industry-standard degradation rates apply.
Installation
The system was designed and installed by Chiltern Solar Ltd, an MCS-accredited (NAP 28870) company and a Renewable Energy Assurance Scheme (RECC) member (No. 44711). The project included:
Full mechanical and electrical installation
Inverter programming
System commissioning
Warranties and Guarantees
JA Solar Modules: 25-year product warranty, 30-year performance warranty
Solis Inverter: 5-year manufacturer warranty
Chiltern Solar Installation: 5-year workmanship warranty
Installed and commissioned by
System overview
View the hardware that we installed for this customer.
340
solar panels
Full list of hardware installed
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