SOLAR POWER CALCULATOR / BIRMINGHAM
What could solar
do for your home?
Explore solar generation, electricity purchases and export income. Compare the same home with solar alone and with a battery, using assumptions you can change.
YOUR ILLUSTRATIVE ANNUAL COMPARISON
See what changes with storage.
Solar alone
Reduced electricity purchases + export income
Solar + battery
Reduced electricity purchases + export income
| Measure | Solar alone | Solar + battery |
|---|
Generation through the year
Monthly generation from the same historical reference year, rounded to kWh.
Benefits are before installation, maintenance, replacements, degradation and finance costs. Standing charges remain payable. This model does not establish whether the investment will pay back.
Turn this scenario into a property assessment.
Your roof, equipment, usage and actual tariff need to be checked before choosing a system.
Discuss my solar options →How this calculator works
The generation profiles come from the European Commission’s PVGIS 5.3 service, using the PVGIS-SARAH3 dataset for Birmingham city centre (52.4862, −1.8904). They cover 8,760 hourly samples from 2023, a fixed 35° roof, crystalline-silicon panels and a 14% system-loss input. The east–west option splits the array equally between those directions.
This is a historical reference scenario, not a forecast or a site survey. A different year, roof pitch, location or shading pattern will change output. The shading control applies a simple proportional reduction; it does not map trees, buildings or individual panel shading. The model scales generation with array size and does not model a specific inverter’s clipping.
Your annual demand is spread across an illustrative hourly pattern, with British Summer Time accounted for and no seasonal change in daily consumption. Actual smart-meter data would provide a stronger basis. Solar serves demand first, then charges the battery; remaining surplus is exported. Storage can serve later demand within its usable capacity and power limits, with conversion losses included. The battery starts empty; any energy left at year-end is not counted as a saving.
Electricity purchases avoided are valued at the import rate you enter. Export income uses your entered export rate. The additional battery benefit deducts the export income lost when surplus is stored. These are operating benefits before equipment and other costs. The default rates are examples, and no export eligibility or tariff offer is assumed.
The model excludes grid charging, changing tariff rates, battery standby use, degradation, backup reserves and detailed appliance behaviour. It is intended for an initial domestic comparison. Commercial systems and standalone batteries need a separate assessment.
PVGIS data and method documentation ↗ · Data retrieved 26 October 2026. Inputs are calculated in your browser; the calculator does not submit them as an enquiry.
Understanding your solar estimate
Is the result a guaranteed saving?
No. It is an illustration using your inputs, a historical generation profile and a simplified household demand pattern. Your actual roof, consumption and tariff need to be assessed. Installation, maintenance and other ownership costs are outside the result.
Why is the battery benefit smaller than the total saving?
The solar panels already provide a benefit without storage. The extra battery benefit is the difference between the two scenarios, including storage losses and reduced export income. This is the relevant starting point when considering a retrofit battery.
Can I use this for a battery without solar?
This calculator charges the battery from surplus solar only. Setting solar capacity to zero therefore produces no battery benefit. A standalone battery needs a model of your tariff periods, charging costs and demand.
What should I do with the result?
Compare a few realistic scenarios, then ask for a property assessment. Our home solar systems guide and battery sizing guide explain the next choices.
Get an assessment built around your property.
Tell us what you have in mind. We’ll help you understand the options and the next step.