CEB Tariff Based Solar Sizing

Solar System Size Calculator

Enter the customer category and current monthly bill. The calculator shows how that bill converts into estimated units, then sizes solar and battery capacity from the result.

Using The Latest Tariff Table

Consumption tariffs are based on the approved CEB tariff table effective from April 1, 2026.

Solar export payment bands still use the RTSPV tariff document you provided earlier; update that table separately if CEB issues a newer RTSPV purchase tariff.

Customer Inputs

The bill amount should be the total monthly CEB bill in Sri Lankan Rupees. Customers only choose Domestic, General Purpose, or Industrial; CEB Rate 1/2/3 can be selected where it applies.

Shown for General Purpose and Industrial customers only.
Used for Rate 2/3 categories only.
kWh produced per 1 kW solar per day after losses.
100% sizes solar to match estimated monthly units.
LiFePO4 systems commonly use 80-90% usable capacity.

Recommended System

This is a preliminary sizing estimate for customer qualification. Final design should use the actual CEB bill, load profile, roof area, inverter limits, and site shading.

Minimum Solar Capacity
0.0kW
Matching estimated monthly consumption.
Battery Capacity
0.0kWh
For selected backup level and hours.
Estimated Monthly Units
0kWh
Back-calculated from selected CEB tariff.
CEB Export Payment Band
0.00Rs/kWh
Based on estimated AC capacity range.

Calculation Summary

Estimated daily consumption0 kWh/day
Estimated monthly solar production0 kWh/month
Approx. monthly CEB export valueRs. 0
Estimated average load0 kW
Tariff model usedDomestic

How The Bill Converts To Units

Entered bill is reverse-calculated against the selected CEB tariff until the reconstructed bill matches.

Charge line Units / Basis Rate Amount
Reconstructed bill total Rs. 0
Energy charge plus fixed charge plus 2.5% SSCL.
This is a fast estimate. For Rate 2/3 customers, demand charges can remain even after solar because they are based on kVA demand, not kWh energy.

Rooftop Solar Export Payments

Flat tariff for 20 years by installed AC capacity.

Installed CapacityRs/kWh
0 up to 5 kW20.90
Above 5 up to 20 kW19.61
Above 20 up to 100 kW17.46
Above 100 up to 500 kW15.49
Above 500 up to below 1,000 kW15.07
1 MW and over14.46

How Battery Is Estimated

Battery capacity is not set by CEB tariff. It depends on what the customer wants to keep powered during outages or peak periods.

ModeLoad Coverage
Essential30% of average site load
Comfort60% of average site load
Whole Site100% of average site load