Solar Calculator Bihar 2026
See panel size, PM Surya Ghar subsidy and monthly savings for your home under NBPDCL or SBPDCL.
1 Your electricity
Enter your 6-digit PIN to auto-fill your district's average daily generation from NASA satellite data. You can always edit it below.
Indian residential tariffs typically run ₹6–₹9 per unit and rise every year. Check a recent bill for your exact slab rate.
2 Cost & generation
A complete on-grid setup (panels, inverter, structure, wiring, installation) runs about ₹50,000–₹60,000 per kW in 2026. Tier-1 brands (Tata, Adani, Waaree) cost a little more.
Most of India gets about 4 units (kWh) per kW per day on average; sunnier states (Rajasthan, Gujarat) can reach 4.5–5.
3 Subsidy & state top-up
Central subsidy: ₹30,000/kW up to 2 kW, +₹18,000 for the 3rd kW, capped at ₹78,000 for any system 3 kW and above (residential, up to 10 kW). As of May 2026 (per MNRE). Always confirm current rates at pmsuryaghar.gov.in before applying.
Some states add their own subsidy on top of the central one (e.g. Gujarat has offered ₹10,000/kW). Enter your state's per-kW top-up if any — leave 0 if unsure. Verify with your DISCOM.
4 How you'll pay
Indicative estimates only. Subsidy rules and tariffs change by government notification and vary by state/DISCOM. Assumes a gradual annual tariff rise and panel degradation. Confirm current PM Surya Ghar rates and get installer quotes before purchasing.
How PM Surya Ghar subsidy is calculated
• Up to 2 kW:
₹30,000 per kW (1 kW = ₹30,000; 2 kW = ₹60,000)• 3rd kW:
+₹18,000 (so 3 kW = ₹78,000)• 3 kW and above: capped at
₹78,000 (no extra above 3 kW; residential eligibility up to 10 kW)Net cost =
system cost − central subsidy − state top-up. Annual savings = annual units generated × tariff (capped at your usage). Payback = net cost ÷ annual savings; the free-electricity date is today plus the payback period. Source: Ministry of New & Renewable Energy / pmsuryaghar.gov.in — verify current values before applying.
Rooftop Solar in Bihar
Bihar is served by two state DISCOMs under the BSEB umbrella: NBPDCL covering the districts north of the Ganga and SBPDCL to the south, including Patna. Both follow BERC tariff orders and the same net-metering framework, so the rooftop process is consistent across the state.
Net metering and tariffs
BERC has waived application and meter-testing charges for residential rooftop systems under PM Surya Ghar, and in 2026 it approved the power-purchase and energy-accounting framework for a large 275 MW rooftop programme. Bihar carries one of the highest opening domestic slabs in the country, though the state government also cushions bills with tariff subsidy and, more recently, a free-units allowance for low consumption. For a solar owner the practical figure is the rate you avoid on the units your panels replace, often around Rs 7 per unit for a mid-sized home.
Sunshine and generation
The Gangetic plain sees decent sun, averaging near 4.2 units per kW per day, a little lower than the arid west because of summer haze and monsoon cloud. A 3 kW system generates roughly 4,600 units a year. Size yours against your bill with the system size calculator.
How PM Surya Ghar applies
The national scheme pays Rs 30,000 per kW for the first 2 kW and Rs 18,000 for the third, capped at Rs 78,000 for 3 kW and above, credited by DBT after commissioning. A collateral-free loan near 7 percent covers up to Rs 2 lakh, so model the instalments with the loan EMI calculator.
- Up to 2 kW: Rs 30,000 per kW
- 3 kW and above: Rs 78,000 total
Worked example
Consider a 3 kW rooftop in Patna. At about 4.2 units per kW it produces close to 4,600 units annually. Offset at roughly Rs 7 per unit, that is near Rs 32,000 saved each year before export credit, and after the Rs 78,000 subsidy the net outlay is modest. Check the numbers with our on-grid calculator and estimate long-run returns using the savings calculator. If you also want backup during outages, size storage with the battery bank calculator.
Because Bihar bills, subsidies and free-unit rules change from year to year, treat these numbers as indicative and confirm the latest BERC order before ordering a system.
Solar generation in Bihar, month by month
From PVGIS 5.3 (European Commission Joint Research Centre), ERA5 solar data 2005-2023: a 1 kW grid-tied system at the best fixed angle with 14% system losses. Figures are the average of Patna, Gaya, Muzaffarpur. The calculator above uses 4.2 units per kW per day as its default.
| Month | units per kW per day | 3 kW system, units in the month |
|---|---|---|
| January | 4.7 | 440 |
| February | 5.1 | 428 |
| March | 5.1 | 477 |
| April | 4.9 | 440 |
| May | 4.3 | 402 |
| June | 3.5 | 318 |
| July | 2.8 | 262 |
| August | 3.0 | 283 |
| September | 3.4 | 303 |
| October | 4.2 | 386 |
| November | 4.6 | 414 |
| December | 4.6 | 429 |
Solar output by city
| City | units/kW/day | units/kW/year | 3 kW, units/year | Best tilt |
|---|---|---|---|---|
| Gaya | 4.2 | 1,533 | 4,598 | 29° |
| Patna | 4.2 | 1,530 | 4,591 | 30° |
| Muzaffarpur | 4.2 | 1,520 | 4,559 | 31° |
What each system size produces in Bihar
| System | units per day | units per month | units per year |
|---|---|---|---|
| 1 kW | 4.2 | 127 | 1,528 |
| 2 kW | 8.4 | 255 | 3,055 |
| 3 kW | 12.6 | 382 | 4,583 |
| 5 kW | 20.9 | 636 | 7,638 |
| 10 kW | 41.8 | 1,273 | 15,275 |
How Bihar compares
Bihar ranks #16 of 36 states and union territories for output per kW: 1,528 units a year, 2% above the middle state (1,495). The range runs from 1,150 in Sikkim to 1,939 in Ladakh — see the full state ranking.
Solar calculators for nearby states & UTs
Compare subsidy, tariff and net-metering figures with the neighbouring states, or see all 36 in the India states directory and the national India solar calculator.
Frequently asked questions
NBPDCL north of the Ganga or SBPDCL to the south, both under BSEB and BERC rules; you apply through the national PM Surya Ghar portal.
There is no separate per-kW state capital subsidy at present; residents rely on the central PM Surya Ghar amount of up to Rs 78,000 for 3 kW, though the state does subsidise general electricity tariffs.
About 4.2 units a day on average, near 1,530 units a year, depending on season, dust and shading.
Yes, BERC has waived application and meter-testing charges for residential rooftop solar under PM Surya Ghar; installation and metering hardware costs still apply.
About 13 units a day or 4,583 units a year on average, from about 8.5 a day in July to 15.4 a day in March, according to PVGIS data for panels at the best fixed angle. Shading, dust and orientation change the result.
Learn more
Sources & standards
The subsidy amounts, net-metering rules and tariff figures used for Bihar come from these central and state sources.
- PVGIS 5.3 — Photovoltaic Geographical Information System — European Commission, Joint Research Centre
Monthly and annual output per kW for Patna, Gaya, Muzaffarpur (ERA5, 2005-2023; 14% losses, optimal fixed angle). Retrieved 2026-11-09. - Ministry of New and Renewable Energy — MNRE
The central ministry that designs and administers India's rooftop solar subsidy programme applied in this calculator. - PM Surya Ghar: Muft Bijli Yojana — Government of India
Official portal for the central subsidy of up to ₹78,000 for a 3 kW-plus system, the basis for the figures above. - Bihar Electricity Regulatory Commission — BERC
Approves Bihar's net-metering regulations, tariff orders and the rooftop PPA/accounting framework referenced above. - IEC 61215 & IEC 61730 — International Electrotechnical Commission
The module design-qualification and safety standards behind the equipment quality assumptions used here.