One of the most common surprises Heaven Green Energy customers report in the first quarter after commissioning is this: “My solar is generating perfectly, but my electricity bill still shows ₹400 — why?” The expectation across most rooftop solar buyers in 2026 is a flat zero on the bottom line. The reality, even for a well-sized 5 kW (kilowatt) system on a 5 kW sanctioned load home, is a residual bill of ₹200–800 every month — and that residual is structural, not a fault in your system. Solar offsets the energy charge portion of your bill. It does not offset fixed charges, fuel adjustments, duties, meter rent, or the export-import differential that kicks in every night.
This guide walks through the six components of an Indian electricity bill that survive a solar installation, the regulatory reason each one continues, the state-by-state variation in residual amounts, and how to set realistic expectations before you sign a quote.
Direct answer. Solar does not zero your electricity bill because five components continue after net metering: fixed charges (₹50–150/month per kW sanctioned), fuel adjustment charge (FAC/PPAC, variable), electricity duty (ED, 5–10% of bill), meter rent (₹15–50/month), and the night-time import–day-time export tariff differential. Typical residual for a residential consumer in 2026 is ₹200–800/month.
If your installer promised you a zero bill, that’s a sales line, not a regulatory outcome. The honest framing is: solar reduces your bill to 5–15% of its original value — which on a ₹6,000 monthly bill is a residual of ₹300–900, paying back the system in 3–5 years regardless.
Anatomy of an Indian Electricity Bill — What You Actually Pay For
Before you can understand why solar doesn’t zero a bill, you have to know what the bill actually contains. A residential electricity bill issued by any DISCOM (Distribution Company) in India is built from six line items, each governed by a separate regulatory order from the State Electricity Regulatory Commission (SERC).
| Bill component | What it pays for | Offset by solar? | Typical share |
|---|---|---|---|
| Energy charge (₹/kWh × units) | Actual electricity consumed | Yes — net metering credits exports | 55–70% |
| Fixed charge (₹/kW × sanctioned load) | DISCOM infrastructure & capacity reservation | No — flat monthly | 8–15% |
| Fuel Adjustment Charge (FAC/PPAC) | DISCOM’s coal/gas/PPA cost variations | No — applied on net units | 5–12% |
| Electricity Duty (ED) | State government tax on consumption | No — passes through on bill total | 5–10% |
| Meter rent | Meter ownership & maintenance | No — flat | 1–3% |
| Other surcharges (TOD, wheeling) | Time-of-day & infrastructure | Partial | 0–5% |
Only the energy charge row is fully offset by solar through net metering. Everything else continues. This is the structural truth that all of MNRE, MERC, GERC, and the Maharashtra DISCOM tariff orders make clear in their published rate schedules — solar self-consumption nets only the kWh component.
The energy charge share matters because if your bill is 70% energy charge and 30% other components, the absolute maximum bill reduction solar can deliver is 70%. The remaining 30% — fixed charges, FAC, ED, meter rent, duty surcharges — survives every kilowatt-hour you generate.
The 6-Component Residual Bill After Solar
Heaven Green Energy uses a six-component framework — The 6-Component Residual Bill After Solar — to break down exactly what survives a perfectly installed rooftop system. Every one of these is regulated, every one is non-negotiable, and every one is why your bill has a number on the bottom line even when your inverter shows 100% offset.
| # | Component | Why it survives | Typical monthly amount |
|---|---|---|---|
| 1 | Fixed charges | Capacity reservation, not consumption | ₹50–600 (load-dependent) |
| 2 | Fuel Adjustment Charge (FAC/PPAC) | Pass-through on imports & net units | ₹50–250 |
| 3 | Electricity Duty (ED) | State tax on the bill total | ₹40–200 |
| 4 | Meter rent | Asset rent, not usage | ₹15–50 |
| 5 | Demand charges (C&I only) | Peak kVA (kilovolt-ampere) booking | ₹0 residential / ₹2,000+ commercial |
| 6 | Security deposit reconciliation | Annual revision on consumption | Periodic, not monthly |
Add components 1–4 for a residential consumer and you arrive at a typical residual of ₹200–800/month. The exact figure depends on your sanctioned load, state, DISCOM, and consumption profile. We’ll walk each component below.
This framework is what we explain to every Heaven Green customer at the quote stage — alongside the solar payback period calculation — so that the post-installation bill is exactly what they expected, not a surprise.
Fixed Charges Continue Even at Zero Consumption
Fixed charges are the single biggest source of confusion. They are billed per kW of sanctioned load, not per kW consumed. A home with a 5 kW sanctioned load pays the fixed charge whether the meter reads 0 or 500 units that month. Solar cannot make this number disappear — the only way to reduce it is to apply for a sanctioned-load reduction with the DISCOM, which is rarely sensible because your air-conditioner load doesn’t shrink just because you installed solar.
State-by-state fixed charges for 2026 are roughly:
| State / DISCOM | Fixed charge (₹/kW/month) | 5 kW sanctioned home pays |
|---|---|---|
| Gujarat (PGVCL, DGVCL, MGVCL, UGVCL) | ₹15–25 | ₹75–125/month |
| Maharashtra (MSEDCL) | ₹100–135 | ₹500–675/month |
| Tamil Nadu (TNPDCL) | ₹60–80 | ₹300–400/month |
| Delhi (BSES, TPDDL) | ₹125–250 | ₹625–1,250/month |
| Karnataka (BESCOM) | ₹85–115 | ₹425–575/month |
| Rajasthan (JVVNL, JdVVNL, AVVNL) | ₹50–110 | ₹250–550/month |
| Uttar Pradesh (UPPCL) | ₹80–120 | ₹400–600/month |
Source: state SERC tariff orders, 2025–26 schedule. This is why Gujarat consumers report the smallest residual after solar — a 5 kW Gujarat home pays ₹100 in fixed charges, whereas the same home in Mumbai pays ₹600. Same panels, same generation, very different bill bottom-line. If you’re in MSEDCL territory and read why solar bills stay high, this is the primary reason.
The other reason fixed charges survive solar: the DISCOM still has to maintain the wires, transformer, and connection to your home even on cloudy days and through monsoon. The fixed charge is the regulatory mechanism for recovering that infrastructure cost. It’s the same logic as paying broadband line rental whether or not you stream Netflix that month.
Demand Charges for Commercial / Industrial Connections
Residential consumers ignore this section — demand charges are a commercial/industrial issue. But if you’re a HT (High Tension) or commercial LT (Low Tension) customer, this is the largest item solar can’t fix.
Demand charges are billed on maximum kVA recorded during the billing period, regardless of how much solar offset your kWh consumption. A small textile unit drawing 80 kVA peak for ten minutes a day pays demand charge on 80 kVA, even if the inverter ran the rest of the day on solar. The MERC and other SERCs structure it this way because the DISCOM has to size its transformer for your peak, not your average.
Solar does reduce demand charges in two cases: (a) if your peak shifts to daylight hours and solar covers it, or (b) if you install a battery and time-shift consumption. Neither is automatic — both require explicit sizing decisions at the quote stage. Heaven Green models demand charge offset alongside energy charge offset for every commercial customer; the resulting ROI (Return on Investment) is closer to the 3 kW vs 5 kW vs 10 kW sizing economics for residential, but with an additional layer.
Free realistic bill estimate from Heaven Green. We analyse your last three bills, break them down by component, and show you exactly what residual to expect after solar. No “₹0 bill” sales pitch. Get your free quote → — or use the Heaven Green solar calculator to model it yourself.
Fuel Adjustment Charge (FAC/PPAC) Cannot Be Offset by Solar
The Fuel Adjustment Charge — also called PPAC (Power Purchase Adjustment Charge) or FPPCA depending on state — is the DISCOM’s mechanism for passing fuel and power purchase cost variations through to the consumer. Coal prices spike in Q2, the DISCOM’s average purchase cost rises, and the FAC for the next quarter goes up by ₹0.30–0.80 per kWh. It applies to net units billed — that is, the units the DISCOM bills you for after netting solar exports against imports.
Two things matter here. First, FAC is applied per kWh of net consumption, not per kWh of gross consumption. So if your net bill shows 50 units (after solar offset), FAC is charged on those 50 units. Second, FAC is never charged on the export side — your exported units earn the APPC (Average Power Purchase Cost, around ₹3.35/kWh) without any fuel adjustment in your favour.
This asymmetry costs solar consumers ₹50–250/month on average. In MSEDCL territory, the FAC line in 2025–26 has averaged ₹0.55–1.20/kWh. For a 100-unit net-import resident, that’s ₹55–120/month of FAC alone, and there is nothing on the system side that reduces it. The only way out is to make the net import smaller — which is what a correctly sized system already does.
Tip
When comparing quotes, ask the installer to model your bill at the current FAC, not at the base energy tariff. A quote that uses only the base ₹6.50/kWh tariff overstates savings by 8–18%. A realistic quote uses the all-in tariff including FAC and ED.
Electricity Duty (ED) Continues
Electricity Duty is a state tax — between 5% and 10% of the bill total depending on the state — and it is the cleanest example of a pass-through cost that survives solar. The duty is calculated on the bill after energy charges, fixed charges, and FAC are computed. Solar reduces the base on which ED is calculated, so the absolute ED falls. But the rate doesn’t move, and ED on the remaining fixed charges and FAC continues to appear on every bill.
State-wise ED rates (2026):
| State | ED rate (residential) | Notes |
|---|---|---|
| Maharashtra | 9.3% | Plus 6% tax on sale of electricity in some categories |
| Gujarat | 7.5% | Domestic; varies for commercial |
| Tamil Nadu | 6% | Plus cess in select municipalities |
| Karnataka | 6–9% | Tiered by consumption |
| Delhi | 5% | Plus 8% PPAC surcharge |
| Rajasthan | 7.5% | Urban; 5% rural |
| Uttar Pradesh | 5% | Plus regulatory surcharge |
ED is collected by the DISCOM on behalf of the state government — neither MNRE nor any solar policy can remove it. A consumer in Maharashtra with a ₹400 residual bill (fixed + FAC + meter rent) pays roughly ₹37 in ED on top, taking the bill to ₹437. This is regulatory and unavoidable.
Night-Time Consumption + Net Metering Differential
The fifth and most under-explained reason your bill isn’t zero is the export-import tariff differential. Net metering doesn’t credit your exports at the same rate you pay for imports — and the gap is significant.
The maths:
- Day-time export rate — surplus solar units exported to the grid are credited at the APPC (Average Power Purchase Cost), around ₹3.35/kWh in most states for 2026 (RERC, MERC, GERC tariff orders).
- Night-time import rate — units you draw from the grid after sunset are charged at the retail tariff, typically ₹6.50–8.50/kWh including FAC.
A typical Indian household consumes 30–40% of its electricity at night — fans, lights, fridge cycles, late-evening AC. The solar plant generates between 7 a.m. and 5 p.m. So your day surplus exports at ₹3.35, your night consumption imports at ₹7+, and the net cash position on identical kWh is negative ₹4 per unit moved through the grid.
Example: a 5 kW home in Pune generates 700 kWh/month. It self-consumes 400 kWh during daytime and exports 300 kWh at APPC. After sunset it imports 250 kWh from the grid at retail. Net bill maths:
- Export credit: 300 × ₹3.35 = ₹1,005
- Import charge: 250 × ₹7.20 (incl. FAC) = ₹1,800
- Net energy charge: ₹795
- Plus fixed charges, ED, meter rent: ~₹650
- Total residual: ~₹1,445
If the export rate had matched the import rate, the residual would have been ₹650. The ₹795 differential is the night-time tariff asymmetry. For more on how this interacts with your existing slabs, read solar and electricity bill slabs. To understand how tariff revisions compound this, see solar and electricity tariff hike.
The only ways to close this gap are: (a) shift more consumption to daytime (run dishwasher, washing machine, water heater between 10 a.m. and 3 p.m.), (b) add a battery to time-shift solar generation to night, or (c) accept the residual as the cost of grid backup. Most residential buyers accept (c).
Common Mistakes That Disappoint Solar Buyers
These are the assumptions we see again and again at consultation stage. Avoid all six and your post-installation experience matches your pre-installation expectation.
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1
"Solar will give me a zero bill." No — it eliminates only the energy charge. Fixed charges, FAC, ED, and meter rent continue. Realistic outcome is 5–15% of original bill.
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2
"Oversizing the system will get me to zero." Net Metering caps residential systems at 10 kW in most states, and the export rate (APPC ₹3.35) is so low that excess generation barely pays back. Diminishing returns past your actual consumption.
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3
"FAC and ED can be claimed back." No — both are statutory pass-throughs. The rate is set by SERC and state government respectively, with no consumer exemption for rooftop solar.
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4
"I can reduce fixed charges by reducing sanctioned load." Only if your actual peak load also drops. Reducing sanctioned load below actual usage triggers MD (Maximum Demand) penalties that exceed the fixed-charge saving.
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5
"Night consumption is free because I generate during the day." No — your day generation exports at ₹3.35, your night consumption imports at ₹7+. The differential is a permanent monthly cost unless you add storage.
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6
"My installer's bill projection will match reality." Only if they modelled FAC and ED — many quotes show "savings" based on base tariff only, overstating by 10–20%. Ask for the all-in tariff calculation.
These six map directly to the underlying regulatory and economic reasons explored above. Catching them at the quote stage saves the disappointment cycle. For sizing context that anticipates these issues, see how to calculate solar ROI.
Oversize for Zero vs Right-Size for ROI
Some consumers, on hearing the residual bill maths, ask: “Can I just install more panels to push the bill to zero?” This is a real choice, and it has trade-offs. Here is the honest comparison.
- Pro: Larger export buffer covers night imports more fully
- Pro: Excess capacity hedges future tariff hikes
- Con: Export rate (APPC ₹3.35) is half the retail rate — paybacks beyond your true consumption
- Con: 10 kW residential NMM cap restricts how big you can go
- Con: Fixed charges and ED still apply — true zero is impossible
- Pro: Each kW pays back at retail tariff — fastest ROI
- Pro: Lower upfront cost, lower roof area
- Pro: Aligns with PM Suryaghar ₹78,000 subsidy cap at 3 kW
- Con: Residual ₹400–800/month remains
- Con: Less buffer against consumption growth
Sizing Impact on Residual Bill
| System size vs consumption | Annual export % | Monthly residual (Maharashtra 5 kW home) | Payback |
|---|---|---|---|
| Under-sized (60% of consumption) | 5% | ₹1,500 | 3.5 yrs |
| Right-sized (95% of consumption) | 15% | ₹500 | 4 yrs |
| Slightly oversized (115%) | 30% | ₹400 | 4.8 yrs |
| Aggressively oversized (140%) | 45% | ₹350 | 6+ yrs |
Verdict. Right-sizing wins on ROI for almost every residential consumer. The marginal ₹100–150 of bill reduction from oversizing comes at a payback penalty of 1–2 years because exported units earn only ₹3.35/kWh against the avoided retail rate of ₹7/kWh. The exception is consumers planning to add an EV (Electric Vehicle) or expand household load in 2–3 years — for them, a 15–20% buffer pays for itself.
For a quantitative sizing exercise on your bill, the Heaven Green solar calculator models both scenarios in 60 seconds. Or compare specific system sizes in 3 kW vs 5 kW vs 10 kW home solar.
Watch out
Installers who quote on a "₹0 bill guarantee" basis are either oversizing aggressively (and hiding the slow payback) or assuming you'll add a battery (which they price separately, surprising you later). A truthful quote calls out the residual bill upfront. If the quote doesn't, walk away.
State-Wise Residual Bill Comparison
The same 5 kW system on a 5 kW sanctioned home delivers very different residual bills across India. Fixed charges dominate the difference, FAC and ED amplify it.
| State / DISCOM | Fixed (₹/mo) | FAC residual (₹/mo) | ED on residual | Typical monthly residual |
|---|---|---|---|---|
| Gujarat (PGVCL / DGVCL) | ₹75–125 | ₹60–120 | ₹15–25 | ₹250–400 |
| Maharashtra (MSEDCL) | ₹500–675 | ₹100–200 | ₹70–110 | ₹600–800 |
| Tamil Nadu (TNPDCL) | ₹300–400 | ₹70–130 | ₹30–50 | ₹400–600 |
| Delhi (BSES Rajdhani / TPDDL) | ₹625–1,250 | ₹50–100 | ₹40–80 | ₹350–550 (lifeline subsidy adjusted) |
| Karnataka (BESCOM) | ₹425–575 | ₹80–150 | ₹40–80 | ₹500–700 |
| Rajasthan (JVVNL) | ₹250–550 | ₹70–140 | ₹30–60 | ₹350–600 |
Source: state SERC tariff orders 2025–26, Heaven Green Energy customer-bill audit, Q1 2026. Gujarat consistently has the lowest residual because GERC fixed charges are exceptionally low. Maharashtra has the highest because MERC’s MSEDCL tariff loads fixed charges to recover infrastructure cost from urban residential. These differentials should drive system sizing decisions — a Gujarat consumer needs less oversizing buffer than a Maharashtra consumer.
How Heaven Green Energy Sets Realistic Bill Expectations
Heaven Green Energy’s policy is straightforward: no installation goes ahead until the customer has signed off on a written residual-bill estimate. Our process:
- Bill audit. We pull your last three monthly bills, break them down by component (energy, fixed, FAC, ED, meter rent), and identify what solar will and won’t offset.
- Sizing recommendation. Based on daytime consumption profile, sanctioned load, roof area, and PM Suryaghar subsidy headroom — covered in our residential solar service page.
- Residual bill projection. A written estimate of your monthly bill post-solar for years 1–5, with FAC and ED modelled at the current SERC schedule, not at base tariff.
- Tariff hike scenarios. We model your residual at +5%, +10%, and +15% retail tariff scenarios so you understand sensitivity. See solar and electricity tariff hike.
- ALMM tier-1 panels and BIS inverters. Quality components mean your system generates the projected kWh, so the residual bill stays at the projected ₹.
- 25-year performance support. O&M (Operations & Maintenance) coverage so panel cleaning, inverter health, and net meter integrity stay where they need to be.
We’re MNRE-empanelled and rank as India’s #1 PM Suryaghar installer on the national portal. Customers who go through our quote process report zero post-installation surprises on their first bill cycle — because we set the residual expectation to the rupee before the quote is signed.
To start: use the solar calculator, browse our residential solar packages, or contact us for a free bill audit.
Frequently Asked Questions
Why doesn’t my electricity bill go to zero after installing solar?
Solar offsets only the energy charge portion of your bill (units consumed × tariff). Five other components continue: fixed charges based on sanctioned load (₹50–150/kW/month), Fuel Adjustment Charge (FAC/PPAC), Electricity Duty (5–10% of bill), meter rent (₹15–50/month), and the export-import differential because grid exports earn ₹3.35/kWh while imports cost ₹6.50–8.50/kWh. Typical residual for a residential consumer is ₹200–800/month depending on state.
What is the typical residual bill for a 5 kW home solar system in India?
For a residential consumer with a 5 kW sanctioned load and matching 5 kW solar system, the monthly residual bill in 2026 ranges from ₹250–400 in Gujarat (lowest fixed charges), ₹400–600 in Tamil Nadu and Karnataka, and ₹600–800 in Maharashtra (highest fixed charges). The variation is driven primarily by state-specific fixed charges and FAC rates set by the respective State Electricity Regulatory Commissions.
Can I oversize my solar system to get a zero electricity bill?
You can oversize, but you cannot reach a true zero bill — fixed charges, electricity duty, and meter rent survive regardless of solar generation. Net metering also caps residential systems at 10 kW in most states. Oversizing beyond your actual consumption pushes payback from 4 years to 6+ years because exported units earn only ₹3.35/kWh against avoided retail of ₹7/kWh. For ROI, right-sizing wins; for hedging against future EV or load growth, a 15–20% buffer is sensible.
Why is FAC (Fuel Adjustment Charge) still on my bill after solar?
FAC, also called PPAC in some states, is a regulatory pass-through that lets the DISCOM recover variations in coal, gas, and power purchase costs. It is applied per kWh of net consumption (after solar offset) and is set quarterly by the State Electricity Regulatory Commission. No rooftop solar policy in India exempts FAC. The only way to reduce it is to reduce your net import — which a correctly sized system already does.
Does solar reduce demand charges for commercial connections?
Solar reduces demand charges only if the peak kVA recorded by the meter coincides with solar generation hours. For a commercial unit whose peak occurs during 10 a.m.–4 p.m., solar can lower the recorded maximum demand and reduce demand charges proportionally. For units with evening or night peaks, demand charges continue unchanged unless a battery is added. Heaven Green models this explicitly for every commercial quote.
What is the difference between APPC and retail tariff in net metering?
APPC (Average Power Purchase Cost) is the rate at which DISCOMs credit your exported surplus solar units — around ₹3.35/kWh in 2026 across most states. Retail tariff is what you pay to import units from the grid at night — typically ₹6.50–8.50/kWh including FAC. The gap between the two is the structural reason night-time consumption keeps a residual on your bill even when daytime generation exceeds daytime consumption.
Is electricity duty refundable for solar consumers?
No. Electricity Duty is a state government tax levied under each state’s Electricity Duty Act and applies to all consumers regardless of whether their electricity comes from grid imports or solar self-consumption. No state offers an ED waiver for rooftop solar consumers. The duty is calculated on the bill total after energy and fixed charges, so it falls in absolute terms as your bill shrinks, but the rate remains the same.
Why does my night-time consumption cost more than my day-time export earns?
Net metering policies set by SERCs credit exports at the Average Power Purchase Cost (APPC), the rate at which DISCOMs procure bulk power — around ₹3.35/kWh. Imports are billed at the retail tariff which includes the DISCOM’s distribution margin, fixed cost recovery, FAC, and ED — typically ₹6.50–8.50/kWh. The differential is regulatory, not a billing error. Closing it requires either shifting consumption to daytime hours or installing a battery for time-shift.
How does Heaven Green Energy estimate the realistic post-solar bill?
Our process audits your last three monthly bills, decomposes each into the six bill components (energy, fixed, FAC, ED, meter rent, surcharges), models the offset solar will deliver on the energy portion, and provides a written residual estimate for years 1–5 including tariff escalation sensitivity. The projection is the basis of the quote — no installation proceeds until you have signed off on the realistic residual. This eliminates the post-installation surprise that affects 88% of consumers who go in expecting a zero bill.
