Bob's Home

Overview

• Location: Aylesbury

• Date of Installation: January 2025

• Type: Residential

• Roof Layout: South-East & North-East

• Panel Count: 15 Jinko Tiger Neo 440W N-Type All Black Mono Solar Panels

• System Size: 6.6 kW

System Overview

The proposed solar PV system consisted of:

15 x Jinko Tiger Neo 440W N-Type All Black Mono solar panel

• Model: JKM440N-54HL4R-B

• Total generation capacity: 6.6kWp

Tesla Powerwall 3 + Gateway

• Converts DC electricity from the solar panels into usable AC electricity

• Delivers 11kW discharge & 5kW charge with 13.5kWh of fully useable energy

Fastensol pitched roof mounting system

• Fully MCS accredited

• Designed for various roof types

Performance Estimates

Annual Energy Generation

Using meteorological data and industry-standard calculations, the system's expected output was estimated as:

• Total Generation: 5,115 kWh per year

This estimate was based on the system's location, orientation, and shading factors, using a sunpath diagram to model annual sunlight exposure.

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: 2,686 kWh

• Stored and used via battery: 2,260 kWh

• Exported to the grid: 2,345 kWh

• Losses: 391 kWh

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: 1,000 kg

• Equivalent to:

  • 3,700 miles driven by a diesel car

  • CO₂ absorption of 49 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 £15,527.16 (including VAT at 0%). The estimated payback period was 15 years, with an estimated first year saving of £1,400*

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 the shading affect the system?

• The shading factor for this installation is 1.00, ensuring minimal energy losses due to obstructions.

What is the expected performance over time?

• While solar panels experience slight degradation, the expected energy output remains high due to the efficient technology used in this system.

Can excess electricity be sold back to the grid?

• Yes. The system qualifies for the Smart Export Guarantee (SEG), allowing surplus energy to be fed back into the national grid for payments.

Installation

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

*the above illustration is based on a unit cost of electricity of 22p/kWh and a SEG rate of 15p/kWh