SURYAMANU ROI & SIZING CALCULATOR

Commercial & Industrial Rooftop Solar & BESS Lead Qualifier

🛠️

Calculation Logic

Every number that drives the recommended capacity and the ROI. Change them, name the result, and it becomes a selectable logic in Settings.

Developer mode is on, so the calculator is hidden. Change the numbers, save them under a name, then press "Choose these settings" at the bottom to use that logic in the calculator. The built-in logics () are references and cannot be edited, only copied. The logic marked (default) is the one the calculator opens with.
Pick any saved logic to load its numbers, change what you like, then save at the bottom of the page.
1

Select Project Type

Configure the clean energy system architecture tailored for the facility

☀️
Solar Only (Rooftop)
Zero-export or net-metered rooftop solar to displace daytime grid tariffs. Also covers additional solar for facilities that already have some.
₹3.57 Cr/MW at 1 MW, incl. GST
🔋
BESS Only
Behind-the-meter battery storage for peak demand shaving, TOD evening arbitrage, and diesel displacement.
₹1.8 Cr/MWh (₹1.4 Cr from 5 MWh)
⚡
Solar + BESS (Hybrid)
Combines rooftop solar with battery storage. Stores mid-day surplus and discharges during peak evening tariff slabs.
Min: 50 kWp Solar + 100 kWh BESS
2

Input Customer Electricity Details

Upload electricity bills for automatic extraction or fill the fields manually

📂

Drag & Drop Electricity Bill(s) here or Click to Browse

Upload any Indian Commercial/HT Electricity Bill (PDF, JPG, PNG). Contract Demand, Units, Tariffs, and TOD slabs are extracted automatically.

Or Test with Sample Bills:

🤖 Reading Electricity Bill...

Extracting Sanctioned Load, Energy Units, Demand Charges, and Time-of-Day (TOD) peak hours...

✨

AI Bill Extraction Complete: bill_document.pdf

All fields have been populated below.

Demand charges, base tariff, peak/off-peak TOD windows, and consumption figures have been loaded into Step 3. Please review the numbers below and click "Calculate Detailed ROI & Cashflows" when you are ready.
3

Review & Adjust Connection, Tariff & Sizing Data

All fields are directly extracted from your bill or editable manually. No state tariffs are hardcoded.

Bill & Tariff Parameters
BLANK / READY
Actual Tariff Rates from Bill Directly drives ROI
Time-of-Day (TOD) Slabs from Bill Editable schedule
ToD Slots from Bill Drives sizing and savings
From (hr)To (hr)₹ / unit adj.Units / month
Adjustment is the ₹ per unit added to (+) or taken off (−) the base energy rate in that slot. If left empty, slots are built from the peak / off-peak fields above.
Charges that rise and fall with units bought are counted as saved when solar or a battery cuts grid units. Demand, colony and customer charges are not.
Existing solar details are read from the bill when available. Please verify.
🏠 Rooftop Space & Roof Material
Roughly 70 to 90 sq ft of empty, shadow-free roof is needed per 1 kW of solar (80 sq ft/kW is used for sizing).
Fill in what you know (or upload a bill) and press Submit. Optional extras are under Additional inputs.
➕ Additional inputs to increase proposal accuracy OPTIONAL ▼ Expand

Skip anything the prospect does not know. Each answer replaces an assumption in the proposal.

🕒 Working pattern

Days off and shutdown days reduce the annual savings. The shift count is recorded for the site survey.

📈 Load data they already have

No file loaded. The hourly load shape inside each ToD slot is assumed flat.

🌾 Open land

This calculator sizes rooftop solar only. If there is open land, use the ground-mounted calculator at suryamanu.com/groundsolar_calculator.

🔌 Power outages

The outage answer is recorded for the site survey.
Updates the recommended capacity above with these details.
Recommended System Sizing SURYAMANU PRICING
☀️ Proposed Rooftop Solar Capacity 50 kWp
No minimum Capex: ₹15.0 Lakhs incl. GST Est. Area: ~4,000 sq.ft
🔋 Proposed BESS Energy Capacity 100 kWh
No minimum Capex: ₹18.0 Lakhs (@ ₹1.8 Cr/MWh) Inverter Power: 50 kW (2-Hr C/2)
Capacity is sized to the bill, with no minimum system size.
This calculator is only for Rooftop Solar. If you need ground-mounted solar solution, please use this calculator: suryamanu.com/groundsolar_calculator

🕒 Battery Charging & Discharging Timing Strategy

Computed dynamically from your bill's actual Peak and Off-Peak Time-of-Day (TOD) hours.

Reg 20.3 COMPLIANT DISPATCH
Night Grid Charging
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Charges from grid during off-peak rebate hours. Grid charging during peak is strictly prohibited.
Solar Surplus Charging
10:00 AM – 03:30 PM
Captures peak rooftop solar generation exceeding daytime factory base load at zero fuel cost.
Evening Peak Discharge
--
Discharges to shave peak maximum demand (kVA) and displace high peak TOD surcharge power.
Morning Load / Float
--
Carries plant load ramp-up or remains in standby float ready for midday solar absorption.
⚙️ Advanced Financial & Standard Indian Bank Loan Assumptions ▼ Expand
★

Executive ROI & Financial Feasibility Summary

Projections computed using the exact tariff rates extracted from your bill

Monthly Electricity Savings
₹3.35 L
~40% reduction in monthly bill
Simple Capex Payback
3.2 Yrs
Pre-tax, unlevered
25-Year Net Wealth Created
₹8.95 Cr
Net profit after all O&M & cell servicing
Project Return (IRR)
27.8%
Internal Rate of Return

Direct Capex vs Bank Loan (Opex) Comparison

Notice how the bank loan model creates immediate positive net cash flow from Month 1 because monthly bill savings exceed the bank EMI.

Financial Metric Direct Capex (Self-Funded) Bank Loan
Total Project Cost ₹1.77 Crores ₹1.77 Crores
Upfront Customer Outlay (Day 0) ₹1.77 Crores (100%) ₹44.2 Lakhs (Only 25% Margin Money)
Year 1 Tax Shield (Sec 32 40% AD) ₹17.8 Lakhs saved ₹17.8 Lakhs saved
Monthly Bank EMI ₹0 (Zero EMI) ₹2.15 Lakhs / mo
Net Monthly Benefit (Savings minus EMI) +₹3.35 Lakhs / month +₹1.20 Lakhs / month (POSITIVE DAY 1)
Break-Even / Payback Period 3.2 Years Instant (Positive Cashflow from Month 1)
Debt Service Coverage Ratio (DSCR) N/A 1.56x (Comfortably passes bank gate)
Post-Loan Freedom 100% savings to bottom line 100% savings to bottom line