An on-grid (grid-tied) system connects your panels directly to the utility grid through a bi-directional meter. There are no batteries. When your panels produce more than you consume, the excess flows back to the grid and your meter runs backwards.

How the money works: Under net metering you're billed only on net consumption. Generate 400 units, use 300, and you pay for zero while carrying a 100-unit credit. Some states pay cash for surplus at a buyback rate (₹2–3.5/kWh); others only offset your bill.

Where it wins:

• Cheapest per kWp — no battery, which is 40–50% of an off-grid system
• Only configuration eligible for the PM Surya Ghar subsidy (up to ₹78,000)
• Lowest maintenance — no battery replacement every 5–8 years
• Payback typically 3–5 years in high-tariff states

The catch: During a grid outage an on-grid inverter shuts down automatically — even in bright sunlight. This is mandatory anti-islanding safety so linemen repairing the grid aren't electrocuted by your exported power. If you have 4+ hour daily outages, that's a real problem.

Best for: Urban and semi-urban homes with reliable grid supply and high bills. Under 2 hours of daily outage? This is almost always right.

An off-grid system is self-contained. Panels charge a battery bank during the day; the battery powers your home at night and through outages. You're either not connected to the DISCOM at all, or you keep the connection purely as backup.

How the money works: You're not selling anything. Your return is the electricity bill you avoid entirely, plus the diesel generator you stop running. In areas with 6+ hours of daily load-shedding, DG fuel savings alone often justify the system.

Where it wins:

• Works through blackouts — the single biggest reason people go off-grid
• No DISCOM paperwork, no net metering application, no approval wait
• Essential for remote sites: farmhouses, hill stations, telecom towers
• Replaces diesel generators, which cost ₹18–25 per unit to run

The catch: Batteries are expensive and they die. Lead-acid lasts 4–6 years; lithium (LFP) lasts 10–15 but costs 2.5× upfront. Budget for a full replacement in year 6 with lead-acid. There is also no PM Surya Ghar subsidy for off-grid residential — the scheme requires grid connection and net metering.

Sizing is different: You size for your worst day, not your average. Two consecutive cloudy days with no grid means the battery carries the whole load. Off-grid systems run 30–50% oversized versus on-grid.

Best for: Rural homes, farmhouses, 4+ hours of daily outage, or anyone who cannot tolerate a power cut.

A hybrid system is grid-tied with a battery. It exports surplus like on-grid, but keeps a small battery (2–5 kWh) to run essential loads during outages — lights, fans, fridge, router.

The battery is deliberately undersized. You aren't trying to run the AC through a 6-hour cut; you're keeping the fridge cold and the lights on. That keeps cost far below true off-grid.

Subsidy nuance: Several DISCOMs let the solar portion claim PM Surya Ghar subsidy as long as export capability and a net meter are installed. The battery is never subsidised. Rules vary — confirm before assuming.

Best for: Urban homes with occasional but disruptive outages, home offices, medical equipment. Costs roughly 1.5–1.7× an equivalent on-grid system.

Configure this by choosing On-Grid and enabling battery backup in Step 2.

This is for people who have more space than they need power. A big terrace, a warehouse roof, a shed, half an acre of unused land behind the house. Instead of sizing solar to your own bill, you fill the space and sell the surplus.

The core idea: Your own consumption might need 3 kWp. But you have room for 12 kWp. Those extra 9 kWp generate power you'll never use — so it goes to the grid, and the DISCOM pays you for it.

What you actually earn: Self-consumed units are worth your full tariff (₹5–7.5/kWh) because you avoid buying them. Exported units earn the buyback rate (₹2–3.5/kWh), which is always lower. So the economics are strongest when you use as much as you can and sell the remainder.

Three practical scales:

• Spare rooftop (500–1,500 sq ft): 5–15 kWp. Still residential. PM Surya Ghar: max ₹78,000 central subsidy regardless of size. Same installer and paperwork as a standard home system.
• Warehouse / commercial roof (2,000–10,000 sq ft): 20–100 kWp. Crosses into commercial net metering. No residential subsidy, but accelerated depreciation gives a tax benefit if you have business income.
• Small ground mount (0.25–2 acres): 50–400 kWp. Needs land conversion and a proper DISCOM application. This is where it becomes a genuine business rather than a bill-offset.

The three real constraints:

• Sanctioned load cap. Most states cap your rooftop system at 100–150% of your sanctioned load. If your connection is 5 kW, you may not be allowed to install 15 kWp without upgrading the connection. Check this first — it kills more projects than cost does.
• Subsidy ceiling. PM Surya Ghar is capped at ₹78,000 for any system 3 kW or larger — installing a bigger system gives no additional central subsidy.
• Buyback isn't cash everywhere. Some DISCOMs credit units against future bills rather than paying cash. If you export far more than you consume, those credits may expire unused at year-end.

Realistic returns: A 10 kWp rooftop in a ₹7/kWh state with 50% self-consumption returns roughly 14–16% annually and pays back in 5–6 years. Push self-consumption higher (run the AC, charge an EV during the day) and it improves sharply.

Best for: Homeowners with large terraces, small businesses with warehouse roofs, or anyone sitting on an idle plot near an existing electricity connection.