How to Calculate Solar Electricity Bill in India (Step-by-Step)

Published Thu Mar 26 2026 · Updated Thu Jul 02 2026

> **Quick Summary** > - **Average Generation:** 120 Units/kW per month (NCR) > - **Monthly Savings:** ₹2,400 to ₹15,000+ (depending on system size) > - **Payback Period:** 3–4 years for residential systems > - **Primary Mechanism:** Net Metering (Export - Import) > - **Subsidy:** Up to ₹78,000 via PM Surya Ghar Yojana

Most Indian homeowners experience a "bill shock" in the peak of summer. You see a bill for ₹12,000, look at your AC running, and wonder if there is an escape. You decide to go solar, but then a new question arises: **How do I actually read this new bill?**

Understanding **how to calculate solar electricity bill** in India is different from reading a standard utility bill. You are no longer just a consumer; you are a "prosumer" (producer + consumer). Whether you are under BSES Rajdhani or TPDDL, the math changes the moment a bidirectional meter is installed on your premises.

In this guide, we will break down the **solar bill calculation India** process step-by-step, ensuring you know exactly why your bill dropped and how to verify the savings yourself.

## 1. Reading Your Electricity Bill: Before vs. After Solar

Before you install solar, your bill is simple: **Units Consumed × Tariff Rate + Fixed Charges + Taxes = Total Bill.**

After solar, the bill introduces three critical new parameters: 1. **Import:** Units you took from the grid (at night or when cloudy). 2. **Export:** Excess units your solar panels sent to the grid. 3. **Net Units:** The difference between Import and Export.

### Sample Bill Comparison: Before vs. After (5kW System)

*Note: In this **electricity bill after solar** example, the negative 400 units are carried forward to the next month as a credit.*

## 2. How Net Metering Credits Work in India

To understand the **net metering bill calculation**, you must understand the flow of energy. Your solar panels first power your home loads (Instantaneous consumption). If your panels produce 5 units an hour but your home only uses 2 units, the remaining 3 units travel through the Net Metering device and out to the government grid.

According to the Ministry of New & Renewable Energy, most Indian states follow a monthly "settlement period."

- **If Export > Import:** You get units credited to your next bill. - **If Import > Export:** You pay for the "Net" units (Import minus Export). - **Annual Settlement:** At the end of the financial year (usually March), any remaining surplus units are typically paid out to you by the DISCOM at a "Pooled Cost" (a lower rate, usually ₹2–₹3 per unit).

For a deeper dive into the technicalities, see our guide on net metering calculation explained.

## 3. Step-by-Step: How to Calculate Solar Electricity Bill

Let’s perform a **solar bill calculation India** for a typical 5kW rooftop system in Delhi.

### The Assumptions: - **System Size:** 5kW - **Avg. Generation:** 600 Units/month (120 units per kW) - **Home Consumption:** 700 Units/month - **Tariff:** ₹8 per unit

### Step 1: Calculate "Self-Consumption" Not all solar energy goes to the grid. Suppose out of the 600 units generated, your home used 200 units directly during the day. - **Total Generation:** 600 - **Directly Used:** 200 - **Exported to Grid:** 400

### Step 2: Calculate "Grid Import" Since your total need was 700 units and you only used 200 units directly from solar, you needed to take the rest from the grid. - **Total Need:** 700 - **Directly Used:** 200 - **Imported from Grid:** 500

### Step 3: Find the Net Billable Units This is the core of **how to calculate solar electricity bill** totals. - **Net Units = Import - Export** - **Net Units = 500 - 400 = 100 Units.**

### Step 4: Add Fixed Charges and Taxes You only pay energy charges on those 100 units. - **Energy Charge:** 100 units × ₹8 = ₹800. - **Fixed Charges:** Approx ₹250. - **Taxes (PPAC/Surcharges):** Approx 10-20% of energy charges.

## 4. Monthly Generation vs. Consumption Example

Generation varies by season. In the summer, you generate more but also use more AC. In the winter, you generate less but consumption drops too.

| Month | Solar Generation (Units) | Home Consumption (Units) | Net Units (Payable/Credit) | | :--- | :--- | :--- | :--- | | **April** | 650 | 800 | 150 (Payable) | | **May** | 700 | 1000 | 300 (Payable) | | **June** | 680 | 1100 | 420 (Payable) | | **October** | 550 | 400 | -150 (Credit) | | **December**| 400 | 300 | -100 (Credit) |

As shown, the electricity bill after solar fluctuates, but over a 12-month period, the credits from sunny months offset the high-usage months.

## 5. Factors That Affect Your Solar Bill

If you find that your **solar bill calculation India** results don't match your actual bill, check these four factors:

### A. Panel Soiling (The 25% Power Loss) In dusty regions like Noida or Gurgaon, dust accumulation can reduce generation by up to 25%. If your panels are dirty, your "Export" units will drop, increasing your net bill. We recommend a regular cleaning schedule or an AMC service.

### B. PPAC Surcharge In Delhi, BSES and Tata Power apply a Power Purchase Adjustment Cost (PPAC). This is a percentage tax. Even if your net units are zero, you might see a small charge here because it is often calculated on the gross consumption in some commercial categories. Read more about PPAC surcharges here.

### C. Sanctioned Load vs. System Size If your sanctioned load is 5kW, you cannot install a 10kW solar system. If you do, the DISCOM will not grant net metering, and you won't get any credit for the electricity you send back.

### D. Phase Imbalance For three-phase connections, if you have a 3kW solar system on a single phase but your AC is on a different phase, some older meters might not calculate the "Netting" correctly. Modern digital bidirectional meters provided by DISCOMs like BSES or Tata Power DDL have solved this, but it’s worth verifying.

## 6. Real Example: A 3BHK Home in Gurgaon

Mr. Sharma lives in a 3BHK in Palam Vihar. His average monthly bill was ₹9,000 (roughly 1,100 units). He installed a 10kW system with Bridgeway Power.

- **System Cost:** ₹5,50,000 (Bridgeway Tiers) - **Subsidy received:** ₹78,000 (PM Surya Ghar Yojana) - **Net Investment:** ₹4,72,000 - **Avg Monthly Generation:** 1,200 Units - **Avg Monthly Consumption:** 1,100 Units - **New Bill:** ₹350 (Only fixed charges) - **Monthly Savings:** ₹8,650 - **Annual Savings:** ~₹1,03,800 - **Payback Period:** 4.5 Years

Mr. Sharma's **electricity bill after solar** became virtually zero for the energy component. Because he generates 100 units more than he uses on average, he even receives a small payout from DHBVN at the end of the year.

## 7. Common Mistakes in Solar Bill Calculation

1. **Ignoring Fixed Charges:** Solar panels eliminate the *energy charge*, but they do not eliminate the *fixed charge* (based on your sanctioned load) or the *meter rent*. 2. **Confusing Inverter Reading with Bill Reading:** Your solar inverter shows "Total Generation." Your electricity bill only shows "Export." Total Generation - Self Consumption = Export. 3. **Expecting Savings Without Cleaning:** If you don't clean your panels, your **solar bill calculation India** will fail to meet expectations. Dirty panels = Higher bills. 4. **Neglecting the "Slab" Benefit:** In India, electricity is billed in slabs (e.g., 0-200 units are cheap, 400+ units are expensive). Solar keeps you in the lowest, cheapest slab for any remaining import units, which is a hidden way to save more money.

## 8. How to Maximize Your Solar Savings

To make the most of your rooftop solar investment, try to shift your heavy appliance usage (Washing machines, Dishwashers, Water pumps) to the daytime. This is called "Load Shifting." By using solar power directly, you avoid the small conversion losses associated with the grid, and you ensure you aren't reliant on grid stability.

If you are worried about power cuts affecting your savings, consider a Hybrid Solar System which uses batteries to keep your home running even when the grid is down.

## Frequently Asked Questions

### How do I calculate the units generated by my solar panels? A general rule of thumb in India (especially North India/NCR) is that 1kW of solar panels generates 4 units per day on average (120 units per month). Over a year, factoring in monsoon and winter, a 1kW system produces roughly 1,400–1,500 units.

### Why is my solar bill not zero? Even if you generate more than you use, you must pay "Fixed Charges," "Meter Rent," and "Electricity Duty/Taxes." Also, ensure your system is clean; dirty panels lose 20-30% power.

### Does the government pay me for extra units? Yes, via the Net Metering policy. Units are carried forward monthly. At the end of the settlement period (usually March), surplus units are credited to your bank account or adjusted in the next bill at the DISCOM’s "average power purchase cost" (approx. ₹2–₹4/unit).

### What is the difference between Gross Metering and Net Metering? In Net Metering, you use what you need and export the rest (you save at the retail tariff, e.g., ₹8). In Gross Metering, all solar power is exported to the grid at a fixed low rate, and you buy back all your power at the high retail rate. Residents should always opt for Net Metering.

### How much can I save with a 3kW system? A 3kW system generates about 360 units a month. At an average rate of ₹7/unit, you save roughly ₹2,500 per month on energy charges alone. You can compare 3kW vs 5kW systems here to see which fits your roof better.

## Conclusion

Learning **how to calculate solar electricity bill** totals is the first step toward taking control of your energy future. While the initial bill might look confusing with "Import," "Export," and "Net" readings, the math is simple: minimize what you buy, maximize what you produce, and keep those panels clean!

Ready to see how much your specific roof can save? Bridgeway Power has been helping Delhi NCR residents for over 35 years. Use our Solar bill savings calculator — India or contact us for a **free rooftop site survey** today.

Related: see our full guide to rooftop solar installation in India for pricing, sizing, and the end-to-end process.

<figure class="my-6"> <img src="https://jdemxzlvflntfyjnjwyl.supabase.co/storage/v1/object/public/site-assets/blog/technician-inverter-inspection.png" alt="Solar inverter and generation meter inspection India" loading="lazy" decoding="async" width="1200" height="800" class="w-full h-auto rounded-2xl" /> <figcaption class="text-sm text-muted-foreground mt-2 text-center">Post-commissioning inspection — generation and export readings</figcaption> </figure>

## FAQ

### How exactly do slab tariffs work on my Delhi bill? Delhi slabs stack cumulatively: 0–200 units at ₹3/unit, 201–400 at ₹4.50/unit, 401–800 at ₹6.50/unit, 801–1200 at ₹7/unit, above 1200 at ₹8/unit. A 500-unit bill uses all four applicable slabs, not just the top one.

### What is PPAC and why did my bill jump in 2026? Power Purchase Adjustment Charge is a variable surcharge that discoms recover fuel-cost swings through. From April 2026 DERC moved PPAC to monthly recovery — BRPL 17.94%, BYPL 17.43%, TPDDL 16% on energy + fixed + PPAC-base charges. That is why bills rose without a tariff order.

### How does solar cut my bill under net metering? Every unit your solar generates offsets a unit from the top of your slab first (the most expensive one). A 3 kW system generating ~360 units/month typically wipes out the ₹6.50 and ₹7 slabs entirely, saving ₹2,500–3,200 depending on baseline usage.

### What is fixed charge and does solar reduce it? Fixed charge is per kW of sanctioned load, ₹125/kW in Delhi for domestic. Solar does not reduce this — you still pay for the connection. Only energy charges go down.