India has 54 functional distribution companies, and no two run rooftop solar approvals the same way. That is the single most under-appreciated fact in Indian residential solar. A homeowner in Bengaluru, an installer in Pune, and a housing society in North Delhi all apply under the same national PM Surya Ghar scheme — then hit three completely different DISCOM processes with different portals, drawing formats, timelines, and rejection patterns.
This comparison focuses on 3 of the highest-volume DISCOMs in the country: BESCOM (Bangalore Electricity Supply Company, serving Bengaluru and 8 districts of Karnataka), MSEDCL (Maharashtra State Electricity Distribution Company Limited, serving most of Maharashtra outside Mumbai), and TPDDL (Tata Power Delhi Distribution Limited, serving North and Northwest Delhi). Together they process a large share of India’s rooftop solar applications under PM Surya Ghar.
We work with installers operating in all 3 territories, and we track how design and documentation quality affects approval speed. This guide compares the 3 DISCOMs on what actually matters: application flow, technical feasibility timelines, documentation requirements, rejection rates, net metering billing rules, and the practical tactics that cut weeks off each process.
Key Takeaways
- TPDDL and BESCOM approve residential applications fastest: 20–35 days for technical feasibility
- MSEDCL takes 30–45 days and has the strictest documentation format of the three
- Average first-pass rejection rate across India is ~37% — mostly stale templates, not design flaws
- MSEDCL now caps approved capacity based on your trailing 12-month consumption
- The PM Surya Ghar subsidy (Rs 78,000 cap) is identical across all three DISCOMs
- Submitting the net metering application before installation, not after, saves 3–6 weeks
- TPDDL is the most digitized of the three; BESCOM has the best vendor ecosystem
Quick Answer
BESCOM, MSEDCL, and TPDDL all approve residential rooftop solar through 2 parallel tracks: the national PM Surya Ghar portal for subsidy, and a DISCOM-side net metering application for grid connection. BESCOM averages 20–35 days for technical feasibility approval, MSEDCL takes 30–45 days with a detailed 4-sheet drawing format and state-specific annexures, and TPDDL takes 20–35 days under Delhi Electricity Regulatory Commission rules.
The biggest practical difference is documentation strictness. MSEDCL rejects about 38% of first submissions, BESCOM about 30%, and TPDDL about 28%, according to Heaven Designs’ state-by-state DISCOM guide (2026). For homeowners, TPDDL is the smoothest. For installers managing volume, BESCOM’s mature vendor ecosystem makes it the easiest to scale.
In this guide:
- Side-by-side comparison table across 12 process parameters
- How the DISCOM approval process actually works in India
- BESCOM process deep dive: portal, timelines, rejection triggers
- MSEDCL process deep dive: annexures, the 2026 consumption cap, timelines
- TPDDL process deep dive: DERC rules, dual metering, digital-first flow
- Net metering billing and settlement rules compared
- What most installers get wrong about DISCOM approvals
- A practical playbook to cut 3–6 weeks off your timeline
BESCOM vs MSEDCL vs TPDDL: At-a-Glance Comparison
The 3 DISCOMs differ most on approval timeline, documentation format, and billing settlement. BESCOM and TPDDL are faster and simpler; MSEDCL is slower but more predictable once you know its format. Here is the full comparison.
| Parameter | BESCOM (Karnataka) | MSEDCL (Maharashtra) | TPDDL (Delhi) |
|---|---|---|---|
| Regulator | KERC | MERC | DERC |
| Net metering regulation | KERC Net Metering Regulation 2016 (amended 2021) | MERC net metering framework, 2026 consumption cap | DERC net metering regulations |
| Application portal | BESCOM rooftop portal + PM Surya Ghar | Maharashtra Rooftop Solar Portal + PM Surya Ghar | TPDDL online portal + PM Surya Ghar |
| Feasibility timeline (LT) | 20–35 days | 30–45 days | 20–35 days |
| End-to-end timeline | 45–90 days | 60–90 days | 45–75 days |
| Drawing format | BESCOM Rev 3 (updated Q4 2025) | 4 sheets: SLD, GA, key plan, protection scheme | DERC format with dual metering shown |
| Special documentation | Earthing certificate (IS 3043) | Annexure E and F (Annexure E updated 2026) | Dual metering scheme in SLD |
| Capacity cap | Sanctioned load | Trailing 12-month consumption (2026 rule) | Sanctioned load |
| First-pass rejection rate | ~30% | ~38% | ~28% |
| Settlement cycle | Monthly carry-forward (KERC) | Annual settlement | Annual settlement at APPC rate |
| Subsidy (PM Surya Ghar) | Rs 78,000 cap (central) | Rs 78,000 cap (central) | Rs 78,000 cap (central) |
| CEIG threshold | Above 10 kW | Above 10 kW LT; all HT | Above 10 kW |
Timelines and rejection rates from Heaven Designs’ submission database (2025–2026). Subsidy structure per MNRE, PM Surya Ghar portal (2024).
How the DISCOM Approval Process Works in India
Every grid-connected rooftop solar system in India goes through the same 6 stages, regardless of DISCOM. The national rooftop market crossed 17 GW of cumulative capacity in 2026, according to MNRE rooftop solar progress data cited by Heaven Designs — and the DISCOM approval stage remains the leading cause of project delay.
- Portal registration. The homeowner (or vendor on their behalf) registers on the PM Surya Ghar national portal and selects the DISCOM and a registered vendor.
- Technical feasibility application. The vendor files the DISCOM-side application with consumer number, sanctioned load, proposed capacity, and technical documents.
- Feasibility approval. The DISCOM checks transformer capacity, sanctioned load, and consumption history, then issues approval — or a deficiency notice.
- Installation. The vendor installs the system per the approved proposal. Residential installs take 1–2 days.
- Net meter installation and inspection. The DISCOM installs the bidirectional meter and inspects wiring, earthing, and inverter configuration.
- Commissioning and subsidy release. The DISCOM energizes the system for export. The portal releases the subsidy to the homeowner’s bank account after verification.
The average time from submission to approval ranges from 22 days in the fastest states to 57 days in the slowest, according to Heaven Designs (2026). The 3 DISCOMs in this comparison all sit in the faster half of that range — which is exactly why they are worth comparing on the finer details.
Why the Drawing Package Decides Everything
Every DISCOM submission requires the same 5-document stack: a single-line diagram in DISCOM format, a general arrangement layout, module and inverter datasheets, a structural certificate, and the application form. A submission missing any one of these 5 is rejected on administrative grounds before technical review even begins.
BESCOM Process: Karnataka’s High-Volume Workhorse
BESCOM serves Bengaluru and 8 surrounding districts, making it the largest DISCOM in Karnataka by consumer base. Its rooftop solar process runs through the BESCOM rooftop portal in parallel with the PM Surya Ghar portal, under the Karnataka Electricity Regulatory Commission (KERC) Net Metering Regulation 2016, amended 2021.
Timeline and Flow
A typical BESCOM residential project takes 45–90 days end to end. BESCOM approval takes 15–30 days, installation takes 1–2 days, and net metering plus portal verification takes another 30–45 days, according to Karnataka installer process data from Kamal Solar (2026). Technical feasibility approvals on clean submissions run 20–35 days.
What Makes BESCOM Distinct
Format discipline matters more than speed. BESCOM updated its net metering drawing format to “Revision 3” in Q4 2025. Packages submitted with the older Revision 2 format are rejected. The Rev 3 format requires an IS 3043-compliant earthing design shown in the single-line diagram, plus a separate earthing calculation sheet.
Vendor ecosystem is the deepest of the three. Bengaluru has hundreds of PM Surya Ghar-registered vendors, and many include the BESCOM net metering application in the standard installation cost. That competitive pressure keeps service quality high and pricing transparent.
Capacity is capped at sanctioned load. Most homes can install up to 10 kW without a load enhancement, though the subsidy maxes out at 3 kW. A 3 kW system in Bengaluru generates 330–380 units per month in peak months, according to SolarSahi’s Karnataka subsidy guide (2026).
Common BESCOM Rejection Triggers
- Missing earthing certificate or earthing design not shown in the SLD
- Stale Revision 2 drawing templates
- Consumer number not matching the utility bill exactly
- Feasibility applied after installation instead of before
For a BESCOM-specific walkthrough with drawing samples, see the BESCOM solar net metering guide from Heaven Designs, and the Karnataka EPC playbook from QuickEstimate.
MSEDCL Process: Strict, Detailed, and Now Consumption-Capped
MSEDCL is India’s largest state-owned distribution company and serves most of Maharashtra outside Mumbai city. More than 3 lakh Maharashtra consumers had installed rooftop solar by 2025, according to MNRE state-wise data cited by Heaven Green Energy (2025). Volume has not made MSEDCL lenient — it has the most detailed documentation requirements of the 3 DISCOMs here.
Timeline and Flow
MSEDCL technical feasibility approvals run 30–45 days for LT connections, and 45–60 days for HT. Urban suburban areas see 4–8 weeks just for net meter installation, according to SolarSahi’s Mumbai rooftop guide (2026). Plan for 60–90 days end to end.
What Makes MSEDCL Distinct
The 4-sheet drawing format. MSEDCL requires a single-line diagram, general arrangement, key plan, and protection scheme — all with the MSEDCL title block. Submissions must include Annexure E (technical details) and Annexure F (consent letter). MSEDCL updated Annexure E in early 2026; pre-2026 templates are rejected on sight.
The 2026 consumption cap. From February 2026, MSEDCL caps approved rooftop capacity proportionally to the applicant’s trailing 12-month electricity consumption, evaluated automatically by the portal. A household consuming 300 units per month cannot get an 8 kW system approved, regardless of roof space. Systems above 3 kW also face a manual technical feasibility study adding 15–20 days.
Annual settlement. Maharashtra runs an annual net metering settlement cycle. Credits carry forward month to month, and any surplus remaining at year-end is compensated at a DISCOM-determined rate. Rooftop systems in Maharashtra generate 1,400–1,500 units annually per kW, according to ReNova Pulse Energy (2026).
Common MSEDCL Rejection Triggers
- Missing or outdated Annexure E or F
- Consumer number typos, including dropped leading zeros
- Proposed capacity above sanctioned load or above the consumption-based cap
- Bill category showing commercial (LT-2) instead of residential (LT-1) for subsidy applications
For an MSEDCL-specific checklist, see the MSEDCL solar net metering guide from Heaven Designs and the PM Suryaghar MSEDCL process guide from Heaven Green Energy.
TPDDL Process: Delhi’s Digital-First DISCOM
TPDDL is a joint venture between Tata Power and the Government of Delhi, distributing power to North and Northwest Delhi. It operates under Delhi Electricity Regulatory Commission (DERC) net metering regulations and is widely regarded as one of India’s most digitized DISCOMs.
Timeline and Flow
Delhi DISCOMs, including TPDDL, issue technical feasibility approvals in 20–35 days, with a first-pass rejection rate around 28% — the lowest of the 3 compared here. Most residential projects complete in 45–75 days end to end. The application flow is almost fully online: registration, document upload, feasibility tracking, and net meter request all run through TPDDL’s digital channels alongside the PM Surya Ghar portal.
What Makes TPDDL Distinct
DERC format with dual metering. The single-line diagram must explicitly show the dual-metering scheme — the solar generation meter plus the bidirectional net meter. Submissions missing the dual-metering annotation are a leading rejection cause.
Annual settlement at APPC. Surplus units remaining at the end of each financial year are settled at the average power purchase cost determined by DERC. This is a lower rate than the retail tariff, so oversized systems that export heavily see weaker returns — size to consumption, not to roof area.
High urban rooftop density constraints. North Delhi’s older housing stock means more shadow obstructions, shared roofs, and structural questions. TPDDL inspectors pay close attention to structural certificates and earthing at commissioning. Accurate solar shadow analysis software pays for itself here, because a generation estimate that ignores a neighbor’s water tank will not survive the first bill.
Common TPDDL Rejection Triggers
- Dual-metering scheme missing from the SLD
- Structural certificate without a licensed engineer’s registration number
- Address or consumer number mismatch between bill and application
- Group housing applications without RWA authorization documents
Delhi’s subsidy and DISCOM steps are covered in the PM Suryaghar Delhi guide from Heaven Green Energy.
Design Once, Approve Everywhere
SurgePV generates DISCOM-ready layouts, single-line diagrams, and generation reports from one cloud workspace — so your submission survives the first pass.
Book a DemoNo commitment required · 20 minutes · Live project walkthrough
Net Metering and Billing Rules Compared
All 3 DISCOMs use monthly crediting with carry-forward, but the end-of-cycle settlement differs. This is where system sizing mistakes get expensive.
| Billing Parameter | BESCOM | MSEDCL | TPDDL |
|---|---|---|---|
| Credit mechanism | Monthly net of import vs export | Monthly carry-forward | Monthly carry-forward |
| Settlement cycle | Per KERC regulation | Annual | Annual (financial year) |
| Surplus payout rate | KERC-determined | DISCOM-determined | DERC average power purchase cost |
| Banking of excess units | Carried forward | Carried forward to year-end | Carried forward to year-end |
| Capacity basis | Sanctioned load | Trailing 12-month consumption | Sanctioned load |
The practical rule is identical across all 3: size the system to your consumption, not your roof. Every unit you self-consume offsets the full retail tariff. Every unit you export at year-end settles at a fraction of it. Our net metering glossary entry explains the credit mechanics, and the net metering by state and country guide covers how India compares globally.
For billing-accurate proposals, model both scenarios before you quote. SurgePV’s solar yield and financial analysis simulates monthly generation against consumption profiles, so the payback figure in your proposal reflects the real settlement rule — not an optimistic assumption.
What Most Installers Get Wrong About DISCOM Approvals
The biggest misconception in Indian rooftop solar is that DISCOM approval is a post-installation formality. It is not. Feasibility approval is a pre-installation gate, and treating it as paperwork you handle after the crew leaves is the single largest cause of stalled projects and delayed subsidy payments.
Here is what the data says. The average first-pass rejection rate across India is about 37%, and 31% of those rejections trace to wrong drawing formats or stale templates — not engineering errors, according to Heaven Designs’ submission database (2025–2026). Each rejection adds an average of 17 days to the project.
3 more beliefs worth correcting:
- “The subsidy comes from the DISCOM.” Wrong. The Rs 78,000-capped subsidy is central money routed through the PM Surya Ghar portal. The DISCOM only verifies and commissions. Blaming BESCOM for a subsidy delay usually means a portal document was incomplete.
- “Bigger systems are always better value.” Wrong under all 3 DISCOMs, and now structurally wrong under MSEDCL’s consumption cap. Surplus settles below retail everywhere. Oversizing extends payback.
- “All Karnataka or Maharashtra DISCOMs work the same.” Wrong. HESCOM, MESCOM, and GESCOM differ from BESCOM. Mumbai’s Adani, Tata Power, and BEST processes differ from MSEDCL. The format library must match the specific DISCOM on the bill.
Pro Tip
Submit the net metering application the day the customer signs — not the day installation finishes. A 30-day approval clock running in parallel with procurement and installation costs you nothing. Running it after mechanical completion costs you a month of dead time.
Practical Playbook: How to Cut 3–6 Weeks Off Any DISCOM Approval
Across the 3 DISCOMs, the tactics that reliably shorten timelines are the same. We recommend this 7-step sequence to every installer we work with.
- Copy the consumer number character by character. MSEDCL numbers have leading zeros that matter. Consumer number mismatch causes about 7% of all rejections nationally and is 100% preventable.
- Check sanctioned load and bill category first. Proposed capacity must stay within sanctioned load (BESCOM, TPDDL) or the consumption-based cap (MSEDCL). Confirm the bill shows residential (LT-1) before promising the subsidy.
- Upgrade the load before applying, not after a rejection. If the bill shows 3 kW sanctioned load and the customer wants 5 kW, file the load enhancement first. Instant rejection otherwise.
- Use the current drawing format. BESCOM Rev 3 (Q4 2025), MSEDCL Annexure E (2026 update), DERC dual-metering format. Confirm the template version with your design partner before every submission.
- Attach the full 5-document stack on first pass. SLD, general arrangement, datasheets with certification references, structural certificate citing IS 875 Part 3, and the current application form.
- Size to consumption. Target 80–100% of annual consumption offset. In Maharashtra, the portal enforces this; elsewhere, your customer’s payback period enforces it.
- Pre-book the inspection. As soon as installation completes, request the net meter and inspection slot. In MSEDCL territory this step alone can run 4–8 weeks — every day you wait to request it is a day added.
Installers handling 10 or more applications a month should treat DISCOM submissions as a tracked operations pipeline, not a side task. Our PM Surya Ghar guide for EPCs covers the operations side, and the India solar compliance hub maps the full regulatory stack by state. State-specific rules are also documented for Karnataka and Maharashtra.
A clean first submission is the whole game. It is also where design software earns its keep: solar design tools that produces DISCOM-format layouts and generation reports removes the documentation errors behind 9 in 10 rejections. Pair that with solar proposal platform that pre-calculates the PM Surya Ghar subsidy, and the customer-facing side moves as fast as the approval side.
Verdict: Which DISCOM Is Best for Rooftop Solar?
No DISCOM “wins” outright — each favors a different profile. Here is our take after comparing all 3 on speed, strictness, and billing economics.
| Criterion | Best DISCOM | Why |
|---|---|---|
| Fastest approval | TPDDL | 20–35 days, 28% rejection rate, digital-first flow |
| Easiest for installers to scale | BESCOM | Deep vendor ecosystem, predictable Rev 3 format |
| Best billing for high self-consumption | Tie | All 3 credit monthly at retail-equivalent value |
| Worst for oversized systems | MSEDCL | Consumption-based cap blocks oversizing outright |
| Most predictable documentation | TPDDL | DERC format is stable and fully digital |
| Hardest first submission | MSEDCL | 4-sheet format, annexures, 38% rejection rate |
Choose TPDDL territory if you want the smoothest homeowner experience. The process is digital end to end, approval is fast, and rejection risk is the lowest of the 3.
Choose BESCOM territory if you are an installer building volume. The vendor ecosystem is mature, the format is strict but stable, and timelines are competitive. Bengaluru’s upper-slab tariffs make the savings case easy.
Respect MSEDCL if you operate in Maharashtra. It is the strictest of the 3 and got stricter in 2026. But its rules are explicit, and installers who master the annexure format face less competition from sloppy rivals. The consumption cap also protects customers from bad advice — which is good for the market long-term.
Conclusion
BESCOM, MSEDCL, and TPDDL deliver the same outcome — a metered, subsidized, grid-connected rooftop system — through 3 meaningfully different processes. BESCOM balances speed with format discipline. MSEDCL trades speed for the most rigorous documentation and a new consumption-based sizing cap. TPDDL offers the fastest, most digital flow under DERC rules. The subsidy is identical everywhere; the path to it is not.
3 actions to take now:
- Homeowners: check your sanctioned load and bill category on your latest electricity bill before talking to any vendor — it determines your maximum system size and subsidy eligibility in all 3 territories.
- Installers: audit your drawing templates against BESCOM Rev 3 and the 2026 MSEDCL Annexure E today; stale templates cause 31% of rejections and cost 17 days each.
- Everyone: submit the DISCOM application at project kick-off, never after installation — parallel processing is the single cheapest timeline win available.
Frequently Asked Questions
Which DISCOM approves rooftop solar fastest: BESCOM, MSEDCL, or TPDDL?
TPDDL and BESCOM are the fastest, with technical feasibility approvals typically issued in 20–35 days for residential LT connections. MSEDCL averages 30–45 days because of its more detailed drawing format and annexure requirements. Total end-to-end timelines, including meter installation and commissioning, run 45–90 days across all three.
Is the PM Surya Ghar subsidy the same under BESCOM, MSEDCL, and TPDDL?
Yes. The central subsidy is identical nationwide: Rs 30,000 per kW for the first 2 kW and Rs 18,000 for the third kW, capped at Rs 78,000 for systems of 3 kW and above, according to MNRE (2024). The subsidy is paid by the central government, not the DISCOM. What varies by DISCOM is the approval process, timeline, and net metering billing rules.
Can I install solar without DISCOM approval in India?
No. Grid-connected rooftop solar requires technical feasibility approval from your DISCOM before installation, and net metering activation after inspection. Installing without approval means your system cannot legally export power, cannot claim the PM Surya Ghar subsidy, and may face disconnection. Off-grid systems with batteries are the only exception.
What is the first-pass rejection rate for DISCOM net metering applications?
The average first-pass rejection rate across India is about 37%, driven mostly by stale drawing templates and missing annexures rather than technical design flaws, according to Heaven Designs’ submission database (2025–2026). MSEDCL sits near 38%, BESCOM near 30%, and Delhi DISCOMs including TPDDL near 28%.
Does MSEDCL limit solar system size based on my electricity consumption?
Yes. From early 2026, MSEDCL applies a consumption-based cap: the approved rooftop solar capacity must correspond proportionally to your electricity usage over the preceding 12 months, evaluated automatically by the portal. Systems above 3 kW may also face a manual technical feasibility study, adding 15–20 days. BESCOM and TPDDL primarily cap capacity at your sanctioned load.
How long does the full rooftop solar process take under each DISCOM?
Plan for 45–90 days end to end. BESCOM: 15–30 days for portal approval, 1–2 days installation, and 30–45 days for net metering and commissioning. MSEDCL: 30–45 days feasibility approval plus meter and inspection time, so 60–90 days total. TPDDL: 20–35 days approval, with most projects completing in 45–75 days.
Do I need a registered vendor to apply for net metering with BESCOM, MSEDCL, or TPDDL?
For the PM Surya Ghar subsidy, yes — installation must be done by a vendor registered on the national PM Surya Ghar portal, and feasibility approval must be obtained before installation begins. For non-subsidized systems, any installer can technically apply, but DISCOMs process applications far more smoothly when documents come from experienced, portal-registered vendors.
What happens to my excess solar units under each DISCOM’s billing rules?
All three credit exported solar units against your consumption each month. MSEDCL follows an annual settlement cycle where surplus credits left at year-end are compensated at a DISCOM-determined rate. BESCOM carries credits forward under KERC net metering regulations. TPDDL settles surplus at the end of each financial year at the average power purchase cost set by DERC.
