Rooftop on-grid solar looks simple: panels on the shed, meter runs backward, bill drops. In practice, DISCOM rules, ALMM compliance, and vendor quality trip up thousands of farmers every year. By mid-2026, with ALMM List-II live from 1 June 2026, the margin for error is thinner — one wrong purchase can mean no net meter, no subsidy, and no export payment.
This guide covers five mistakes we see repeatedly: non-ALMM hardware, wrong kW sizing, skipping the net-meter application sequence, trusting the wrong vendor, and believing unrealistic ROI. Fix these before you sign a quotation or pay advance.
For ALMM rules and cost impact, read our ALMM List-II on-grid cost guide. For pump and land-scale options, see PM-KUSUM solar farming guide.
From 1 June 2026, net-metering projects commissioned on or after that date must use ALMM List-I modules and ALMM List-II cells. Non-compliant kits are the fastest route to a rejected application.
Mistake 1: Buying non-ALMM or unverified modules
Dealers still offer “import panels, half price” kits. For government-linked and most DISCOM net-metering paths in 2026, that is a dead end.
Why it fails:
- MNRE ALMM List-I (modules) and List-II (cells) are mandatory for applicable projects commissioned from June 2026 onward
- PM Surya Ghar and many state top-ups require listed equipment — subsidy rejection is common on non-listed models
- DISCOM technical scrutiny increasingly asks for model numbers matching the current MNRE list
What to do instead:
- Ask for ALMM List-I module model and List-II cell source in writing on the quotation
- Cross-check on mnre.gov.in before payment
- Keep invoice, serial numbers, and datasheet for inspection
Saving ₹15,000 on panels and losing ₹50,000 in subsidy plus months of delay is not a bargain.
Mistake 2: Wrong kW sizing — too big or too small
Farmers often buy what the dealer stocks — 3 kW when they need 8 kW, or 10 kW when sanctioned load is 5 kW. Both hurt.
| Problem | Symptom | Fix |
|---|---|---|
| Undersized | Bill still high; little export | Sum 12 months of bills; size for peak daytime load (pumps, cold store, house) |
| Oversized | High capital; DISCOM may cap export | Match sanctioned connected load and state net-metering cap |
| Wrong profile | Night-heavy use, tiny daytime export | On-grid saves daytime units; night use still buys from grid |
Practical method:
- Collect 12 electricity bills (kWh and connected load)
- Note when pumps and motors run — solar offsets sun hours
- Ask DISCOM or vendor for a load study — not a WhatsApp guess
A 5 kW system on good roof space might generate 600–750 kWh/month in many Indian states — but your farm may need 1,200 kWh. Numbers vary by state irradiation; treat tables as indicative only.
Mistake 3: Skipping or delaying net-meter application
Some vendors say: “Install now, meter baad mein.” That sequence breaks in most states.
Typical DISCOM flow (varies by state):
- Online application with consumer number, load, and site details
- Feasibility / technical approval (sanctioned load, roof ownership, ALMM list)
- Installation by empaneled vendor (sometimes only after step 2)
- Inspection and net meter installation
- Commissioning and generation certificate where required
If you skip application first:
- You may install non-approved capacity
- Net meter delay means zero export credit while the plant runs
- Commissioning date for ALMM may fall in a stricter compliance window without you planning for it
Action: Download your state DISCOM net-metering procedure (often on the DISCOM website or state renewable energy portal). Submit application before paying large advance. Keep application number and email acknowledgements.
Mistake 4: Bad vendor — cash, no paperwork, fake empaneled status
Solar is a 20-year asset. A fly-by-night installer is expensive.
Red flags:
- 80–100% cash demand with no GST invoice
- No written warranty — 25-year module, 5–10 year inverter
- “Empaneled with DISCOM” with no proof — ask for empanelment letter number
- Guaranteed 30% ROI or payback in 1 year without using your bill
- No ALMM numbers on quote; refuses site visit
Green flags:
- Registered company, GST, past net-metering completion certificates
- ALMM-compliant bill of materials
- Clear split: supply, installation, net-meter liaison, O&M
- Willingness to align with DISCOM application first
Compare two or three quotes. Cheapest per watt is not cheapest if the meter never gets installed.
Mistake 5: Unrealistic ROI and payback promises
Social media shows “₹2 lakh invested, ₹8 lakh return in 2 years.” Farm on-grid economics are good but not magic.
Realistic framing (illustrative — verify locally):
- 5 kW ALMM-compliant system might cost ₹2.5–3.5 lakh all-in post-June 2026 pricing pressure
- Self-consumption at ₹7–9/unit avoids buying from DISCOM
- Export credited at state net-metering / gross tariff — often lower than retail rate
- Simple payback 4–7 years is common in models; 10+ years if export tariff is weak and self-use is low
Include in your model:
- Insurance, inverter replacement reserve (year 10–12)
- Cleaning and wire check annually
- Loan interest if financed
- No subsidy if hardware is non-ALMM
Use your bills, not a dealer’s generic Excel. Bankers and DISCOMs respect documented consumption, not forwarded videos.
Pair on-grid planning with when the grid fails: read on-grid power cut vs.. hybrid options if irrigation must run during outages — standard on-grid shuts down for safety (anti-islanding).
Step-by-step checklist before you pay advance
- Confirm project type — rooftop net metering vs farm open access (different rules)
- Verify ALMM module + cell on official list
- Size from 12 months of bills and sanctioned load
- File net-meter application (or confirm vendor will, with proof)
- Check vendor empanelment and past installations
- Model ROI with your tariffs — reject fantasy payback
- Advance payment — never more than 10–25% until DISCOM steps are clear; rest tied to milestones
Bottom line
On-grid solar rewards patient paperwork and compliant hardware. The five mistakes — non-ALMM kits, wrong kW, meter application skipped, bad vendor, fantasy ROI — are avoidable with one week of verification before money leaves your account.
When in doubt, pause the deal, read ALMM List-II explained, and call your DISCOM helpline with your consumer number. A delayed good project beats a fast rejected one.
Disclaimer: ALMM lists, net-metering rules, and tariffs change by state and DISCOM. Verify on mnre.gov.in and your state DISCOM before investing. Ask Kisan is not a government agency or legal advisor.
Last verified: June 2026.
Frequently asked questions
What is the biggest on-grid solar mistake in 2026?
Buying non-ALMM modules or cells after 1 June 2026 commissioning rules. DISCOMs can reject net-metering, and central or state subsidy may be cancelled. Always verify module and cell ALMM numbers on mnre.gov.in before paying advance.
How do I size on-grid solar kW correctly for a farm?
Match sanctioned load and annual consumption from electricity bills — not dealer guesswork. Oversizing wastes capital; undersizing leaves export credit unused. A 5–10 kW rooftop often suits a medium farm house plus one pump connection; larger open-access needs a separate study. Get a load audit in writing.
Can I install panels before applying for net metering?
Risky. Most DISCOMs require application, feasibility, and sometimes ALMM approval before commissioning. Installing first and applying later leads to rework, rejected meters, or months without export credit. Follow your state DISCOM sequence — application, inspection, meter, then full operation.
How do I spot a bad solar vendor?
Red flags: no ALMM model numbers on quotation, pressure to pay 80% cash today, ROI promises above 25% with no bill data, no DISCOM net-metering experience, and no written warranty for inverter and modules. Compare at least two ALMM-compliant quotes and check vendor GST and past DISCOM approvals.
What is a realistic ROI for farm on-grid solar?
With net-metering at state tariffs and self-consumption savings, many farms see simple payback of roughly 4–7 years on a 5 kW system — not the 18-month WhatsApp claims. Factor in ALMM-compliant hardware cost post-June 2026, O&M, and insurance. Model with your actual units consumed and exported.
