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Select your use case to begin.

Free
Rooftop Solar & Battery

For homeowners and businesses (e.g., hotel, supermarket) looking to install rooftop PV and batteries to reduce electricity bills, and even sell surplus power back to the grid.

  • Breakdown of how much would it cost
  • How much would it save you
  • Solar PV and battery sizing
  • Tailored to households or businesses
Commercial
Ground-Mount/Floating PV & Battery

For project developers evaluating large-scale ground-mounted or floating solar PV systems with direct grid connection. Grid-scale battery storage can also be seamlessly integrated.

  • Ground-mount & floating PV systems
  • Grid-scale battery system
  • Large-scale capacity planning
  • NPV, IRR & full financial analysis

You can switch between modes at any time from within the tool.

Solar & Battery Sizing Platform
Estimate your solar PV & battery system
by OxEnergy
Mode
Load Data
? Low (Flat or 1-bed, 1–2 people): ~1,800 kWh/yr
Medium (2–3 bed, 2–3 people): ~2,700 kWh/yr
High (4+ bed, 4–5 people): ~4,100 kWh/yr
Lat: 51.752, Lon: -1.258
0° = North, 90° = East, 180° = South, 270° = West
? The angle of your roof or panel mounting from horizontal.

0° = flat roof (panels lay horizontal).
20°–35° = typical pitched roof.
90° = vertical wall mount.
? Open-Meteo ERA5: 5-year hourly reanalysis (~25 km). Global coverage. Uses Hay-Davies transposition for tilt/azimuth.

MERRA-2 / CERES: 20+ year satellite + reanalysis climatology (~50 km). Global coverage. Powered by NASA POWER API.
System Specifications
Maximise
Savings
NPV-optimal size: auto-scaled to your system
Self
Sufficiency
Minimum system size to hit your % target
Set your location above to auto-load installation cost estimates for your region.
? Fixed one-time cost regardless of system size. Covers site survey, equipment delivery, scaffolding / access equipment hire, and project management.
? Labour and materials cost per kWp installed. Larger systems benefit from economies of scale where the fixed mobilisation cost is spread across more kWp, reducing the effective total cost per kWp.
Economic Data
? Default value of $0.50/kWh is based on the average UK electricity price of ~£0.30/kWh, converted to USD at approximately £1 = $1.65.

Adjust this value to match your local electricity tariff for accurate savings calculations.
? The rate your utility pays for excess solar electricity exported to the grid (feed-in tariff).

Set to $0.00 if no export tariff is available in your area. In this case, exported energy will earn no revenue and the system will be sized purely on self-consumption savings.
? The discount rate reflects the cost of capital (or opportunity cost) used to calculate NPV. For businesses, this is often the Weighted Average Cost of Capital (WACC).

Need help estimating your WACC? Use this tool: github.com/kathiewildgruber/WACC
0.2 kg CO₂/kWh
Set your location above to auto-load the value for your country.
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No results yet
Enter your parameters and click "Run Optimization" to see results.
Output:
-kWp
Peak system capacity
Generation:
-kWh/yr
Annual production
Irradiance:
-kWh/m²/day
Average daily solar