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Illustrative example · Typical East Midlands site with existing PV
Battery storage and inverter retrofit
A worked example of adding storage to an existing array so generation produced outside working hours is used on site instead of exported at a low rate.
Illustrative worked example
This is not a real client project. Every figure below is modelled from the stated assumptions to show how a system is sized and delivered — it is not measured data, not a quotation and not a performance guarantee. Verified client write-ups and independent reviews will be published here as they are signed off.
The brief
What the client needed
An existing array exports a large share of what it generates. The owner wants that energy retained for early-morning and evening load.
How we approached it
- Half-hourly consumption data reviewed against generation before any battery capacity is proposed.
- Capacity sized to the shortfall actually observed, not to a headline kWh figure.
- Inverters, containment and protection installed and labelled to allow future expansion.
- Monitoring configured so under-performance is visible to the owner, not just to us.
Outcome
In this worked example storage shifts a meaningful share of exported generation into evening use. On a real site the capacity follows the measured export profile and tariff structure.
Project figures
- Usable capacity
- 100 kWh (modelled)
- Source: Illustrative model — not a measured result
- Import reduction
- ≈ 20–30% of annual import (modelled)
- Source: Illustrative model — not a measured result
- Cycles per year
- ≈ 300 (modelled)
- Source: Illustrative model — not a measured result
- Simple payback
- Depends on tariff spread, site-specific
- Source: Illustrative model — not a measured result
These are modelled figures for a worked example, not measured results from a completed installation. Figures for your own site come from the survey.
What this example assumes
This write-up is a worked example built from standard engineering assumptions. It is not a real client project and no figure on it is a measured result.
- Existing PV array already exporting a significant share of summer generation.
- Round-trip efficiency of roughly 90% and one useful cycle most days.
- Static day/night tariff difference; no revenue assumed from flexibility or grid services.
- No allowance for switchgear upgrades, fire strategy works or additional civils.
Read this first
Eligibility and figure caveats
These apply to everything published on this page.
- This is an illustrative model, not a quotation and not a performance guarantee.
- Savings from storage depend on the tariff structure and load pattern. Results modelled for one site do not transfer to another.
- Battery warranty terms are set by the manufacturer and are conditional on cycle count and operating conditions.
Your result will differ
Every figure here relates to this building, this tariff and this pattern of use. Grant schemes, export rates and tax treatment change, and eligibility is confirmed at application by the certified installer or the funding body — not by this page.
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Services used on this project
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