Solar Rooftop Net-Metering Reconciliation for Indian C&I Customers

A 500 kWp rooftop solar plant on a manufacturing facility in Pune generates roughly 6.8 lakh kWh in a year. The DISCOM’s monthly net-metering bill shows an import-export split, a banked-units carry-forward, an energy charge on net import, a demand charge on contracted kVA, electricity duty layered on top, and a cross-subsidy surcharge in some categories. The finance team sees only the net payable hitting the bank statement and the capital block sitting on the fixed-asset register. The two ledgers only agree once five rails are reconciled against one another. Anyone running solar rooftop net metering reconciliation India at C&I scale recognises the pattern — the plumbing looks simple from the dashboard, the leakage hides in the join.

Quick reference

How does the net-metering settlement architecture work?

The bi-directional energy meter sits at the point of common coupling between the rooftop plant and the DISCOM grid. At any instant, the inverter is either pushing power into the consumer’s internal load (self-consumption), pushing power out to the grid (export), or — when the plant is idle and the load is active — drawing power from the grid (import). The meter’s import register accumulates units flowing from grid to consumer; the export register accumulates units flowing from consumer to grid. Self-consumption is invisible to the meter.

In a pure net-metering regime, the DISCOM bills the consumer on the net of import minus export over the billing period. Where export exceeds import in the period, the surplus is banked — added to a running credit that the consumer can draw against in any subsequent month within the financial year. At year-end (the settlement date is typically 31 March across most state regulations), any unutilised banked balance is settled at the Average Pooled Power Cost declared by the state SERC, lapsed, or paid out at a percentage of APPC depending on the state.

Reconciliation has to cover the whole loop. The bi-directional meter is the source of truth on energy. The DISCOM bill is the source of truth on rupees. The banking ledger sits between the two, accruing in months of surplus, drawing down in months of deficit, and resolving at FY close.

What are the five reconciliation rails?

Rail 1 — Bi-directional meter reads vs DISCOM bill

The bi-directional meter records import and export at intervals defined by the meter’s resolution (typically 15-minute interval data for C&I-class meters with a 30-day rolling window). The DISCOM ingests the dump, derives the monthly import and export totals, and prints them on the bill. The consumer’s reconciliation pulls the same dump (via the DISCOM portal where available, or via the handheld unit on the meter visit), aggregates to the bill period, and compares against the bill’s printed import and export line.

Drift can arise from meter-clock skew, register rollover events, late visits by the meter reader (a partial-period read attributed to the prior month), or pure clerical error on bill keying. A drift above the operator’s threshold is a billing-dispute candidate to be filed with the DISCOM consumer-grievance redressal forum within the regulatory window — most state regulations fix this at 60 days from bill date, after which the dispute is barred.

Rail 2 — Banking ledger and APPC year-end settlement

In months where export exceeds import, the surplus units are credited to the banking ledger. In months where import exceeds export, the deficit draws down the banked balance — the consumer pays cash only for the residual deficit after drawdown. The banking ledger must therefore hold a running balance, an ageing of each month’s accrual (some state regulations cap how long a banked unit can be carried), and a projected FY-close residual.

At 31 March (or the FY close date in the relevant state regulation), the residual banked balance is valued at the APPC declared by the SERC for that year. MSEDCL’s APPC, BESCOM’s APPC, TANGEDCO’s APPC, and KSEB’s APPC are distinct numbers and change year on year — using last year’s APPC on this year’s settlement is a common drift. The receipt from the DISCOM (or the credit note against future bills) must be tied against the accrued income recognised through the year.

See DISCOM settlement reconciliation for power generators in India for the upstream view where the same APPC mechanism drives utility-scale power purchase agreements.

Rail 3 — GST on capital invoices and EPC services

The capital block for a rooftop plant typically breaks into three GST treatments:

• PV modules moved out of the historical 5% concessional slab under Notification 8/2021-Central Tax (Rate) effective 1 October 2021, into a higher concessional structure that combines goods and works-contract components into an effective single-digit-plus tax burden. The notification frames the supply as a composite of goods and services with a specified value split, and the consumer captures the tax-inclusive cost on the FAR at this effective rate.
• Inverters, structural mounting, cabling, transformers, and other BOS items fall into the standard 18% slab as electrical equipment under their respective HSN codes.
• EPC services for design, installation, and commissioning are taxed under the works-contract framework that the notification specifies, with the supply treated as a composite of goods plus services.

The reconciliation must split each capital invoice along these three lines so that ITC eligibility is captured correctly (where the consumer is a registered taxable person with output supplies, the ITC on inverters, BOS, and the taxable portion of the EPC supply is claimable subject to the usual eligibility tests), and so that the capitalised cost feeding the fixed-asset register is the right tax-inclusive amount for downstream depreciation.

Rail 4 — Section 32 accelerated depreciation and deferred tax

Solar power generating equipment is a specified renewable-energy asset under the Income Tax Act 2025. The applicable WDV rate is the renewable-energy block rate prescribed in the depreciation schedule. The historical 80% accelerated rate that applied pre-2017 was rationalised down by the Finance Act 2016 to the current renewable-block rate effective for assets capitalised on or after 1 April 2017, and the Act 2025 has preserved that rationalised structure.

Section 32(1)(iia) additional depreciation is available in the year of installation for new plant and machinery acquired and installed in the business of generation, transmission, or distribution of power — including captive generation by the consumer’s own business — subject to the date-of-installation rules (full additional depreciation for assets installed and used for 180 days or more in the year, half for those used for less).

The reconciliation between book depreciation (straight-line over the useful life of the array, typically 25 years for the PV modules with shorter lives for the inverter block) and tax depreciation (WDV at the renewable-block rate plus first-year additional) generates a temporary timing difference that drives a deferred-tax liability through the early years of the asset and a deferred-tax asset in the later years. The DTL must be tracked alongside the FAR and the post-tax project IRR computed using the right cash-tax curve, not the book-tax curve.

Rail 5 — Electricity duty, cross-subsidy surcharge, and bill decomposition

The net payable on a DISCOM net-metering bill is not a single number. It decomposes into:

• Energy charge on the net imported units at the retail tariff applicable to the consumer category (LT-V industrial, HT-1 industrial, LT-II commercial, etc.).
• Demand charge on the contracted kVA, typically per-kVA-per-month flat.
• Fixed charges as defined in the tariff order.
• Electricity duty at the state-specific rate, which ranges from 6% in some states to 25% in others, levied on the net import value.
• Cross-subsidy surcharge where the consumer is in a category that bears CSS (typically open-access industrial consumers), at the rate fixed in the tariff order.
• Net payable that ties to the bank debit on the DISCOM payment date.

Each component goes to a separate GL line in the consumer’s books — bundling them into a single “power and fuel” line breaks the variance analysis that the audit needs at year-end. See electricity duty and state cesses reconciliation for the duty-side decomposition that varies materially across states.

Worked example — 500 kWp rooftop plant on a Pune manufacturing site, FY 2025-26

A 500 kWp rooftop plant on a manufacturing facility under MSEDCL’s HT-1 industrial category generates 6.84 lakh kWh in FY 2025-26 at a specific yield of 1,368 kWh per kWp. Plant load factor on the manufacturing process averages 62%, drawing 14.2 lakh kWh from the grid annually.

Monthly decomposition (averaged):

• Generation: 57,000 kWh per month at the plant.
• Self-consumption (instantaneous match of generation to load): 41,000 kWh per month — invisible to the meter.
• Export to grid: 16,000 kWh per month — registered on the export side of the bi-directional meter.
• Import from grid: 1,18,000 kWh per month — registered on the import side.
• Net billed import: 1,02,000 kWh per month after netting the 16,000 kWh export.

Bill decomposition (typical month):

• Energy charge on 1,02,000 kWh at HT-1 industrial retail tariff (approximately ₹7.50 per kWh including demand-charge-equivalent in MSEDCL’s HT slab): ₹7.65 lakh.
• Demand charge on 1,000 kVA contracted demand at ₹450 per kVA per month: ₹4.50 lakh.
• Fixed charges: ₹0.65 lakh.
• Electricity duty at Maharashtra’s industrial-category rate (approximately 9.3% on the energy charge component): ₹0.71 lakh.
• Net payable: approximately ₹13.51 lakh per month.

Annual reconciliation:

• Total banked-units accrual in surplus months (May, October, November typically): ~18,000 kWh.
• Total drawdown against deficit months: ~14,500 kWh.
• FY-close residual banked balance: 3,500 kWh, valued at MSEDCL’s declared APPC for FY 2025-26 (approximately ₹4.20 per kWh in recent years — the consumer must use the actual SERC-declared number for the relevant FY): ~₹14,700 receivable from DISCOM at year-end.

Capital reconciliation (asset capitalised 1 April 2025):

• Total project cost: ₹2.40 crore. PV modules ₹1.20 crore at the Notification 8/2021 effective treatment, inverters and BOS ₹0.65 crore at 18% GST, EPC services ₹0.55 crore at works-contract treatment. ITC claimed on the eligible taxable lines, balance capitalised on the FAR.
• Book depreciation Year 1 (SLM 25 years): ₹9.60 lakh.
• Tax depreciation Year 1 (renewable-block WDV plus 32(1)(iia) additional, with the full-year application as the asset was in use for more than 180 days in FY 2025-26): substantially higher than book depreciation, generating a Year 1 deferred-tax liability accrual of several lakh rupees — the exact number turns on the renewable-block WDV rate as notified.

Reconciliation drift across the rails for FY 2025-26: 1.4% of total bill value, predominantly in meter-clock skew on two months and a minor APPC mis-valuation that was caught and corrected at audit.

What are the operational controls that close the gap?

The C&I customer who runs a clean rooftop net-metering reconciliation does six things:

1. Monthly bi-directional meter dump pull — do not wait for the DISCOM bill to land. Pull the dump on the bill-date schedule, derive import and export totals independently, and compare against the bill when it arrives. The dispute window starts on the bill date and closes fast.
2. Banking ledger under change control — every month’s accrual, every month’s drawdown, every ageing bucket. The FY-close APPC settlement is a small number relative to total bill value, but it is the most disputed line at year-end audit.
3. APPC schedule table by DISCOM by FY — use the SERC-declared APPC for the relevant FY, not a stale number. The schedule must be refreshed every April from the SERC’s tariff order publication.
4. Capital-invoice GST split at the line level — PV modules, inverters and BOS, and EPC services to three separate ledgers feeding the FAR. ITC claims and capitalised cost both depend on the split being right at first capture.
5. Parallel book and tax depreciation ledgers — book SLM and tax WDV plus 32(1)(iia) additional run in parallel, with the deferred-tax movement booked monthly so the year-end tax provision is computed off a known base.
6. Bill decomposition into separate GL lines — energy, demand, fixed, duty, surcharge, and net payable each to their own GL. The audit’s CARO 2020 IFC walk-through reads variance against budget at this level, not at a bundled “power” line.

These are operational controls, not technology controls. The reconciliation layer makes them auditable and chase-able. Without the layer, the controls degrade to year-end firefighting and the 1% to 3% drift band becomes the 5% to 7% drift band that is no longer tolerable when the post-tax IRR on the project is computed off the actual cash-tax curve.

How does solar net-metering reconciliation interact with the broader power-utility tax stack?

A C&I customer with rooftop solar does not run net-metering in isolation. The same customer carries:

• Conventional grid supply for the deficit — see DISCOM tariff true-up reconciliation under MERC/KERC for the annual true-up where the retail tariff itself is revised against the regulatory revenue requirement and consumers receive credits or debits against the deemed-applicable tariff for the period.
• Electricity duty and state cesses layered on the net import — see electricity duty and state cesses reconciliation for the state-by-state decomposition that matters when the consumer operates plants in more than one state.
• Section 80-IA tax holiday (where the consumer elects under the legacy provision for power-generation business income) and the interaction with the renewable-energy block depreciation — the two interact at the deferred-tax computation and the cash-tax curve.

The net-metering reconciliation is one rail in a five-rail stack — meter-vs-bill, banking, GST split, depreciation, and bill decomposition. A clean rail-by-rail close is what the audit reads in the IFC walk-through for the renewable-asset block. See DISCOM settlement reconciliation for power generators in India for the foundational settlement view that ties the same APPC mechanism into the consumer’s books.

Continue reading in the Power & Utility cluster

• DISCOM settlement reconciliation for power generators in India
• Electricity duty and state cesses reconciliation
• DISCOM tariff true-up reconciliation under MERC/KERC