Bihar Caps Rooftop Solar Net Metering at 500 kW: What Changes Now

Bihar's rooftop solar landscape is set for a significant regulatory reset. The Bihar Electricity Regulatory Commission (BERC) has proposed amendments to its rooftop solar regulations that would cap net metering eligibility at 500 kW per connection and revise the compensation mechanism for surplus electricity fed back into the state grid. The draft amendments, if finalised, will directly affect commercial, industrial, and large residential consumers in Bihar who have installed — or plan to install — rooftop solar systems above this threshold. Under the proposed framework, consumers with capacities exceeding 500 kW would likely be shifted to a net billing or gross metering arrangement, where surplus power is compensated at a rate determined by the regulator rather than offset one-to-one against consumption. Bihar currently has modest rooftop solar penetration compared to states like Gujarat and Rajasthan, but the move signals that the BERC is tightening grid-management rules as distributed solar generation begins to scale. With India's PM Surya Ghar scheme targeting one crore households and the country's 500 GW renewable energy goal by 2030 looming large, Bihar's regulatory pivot carries implications well beyond its own state borders.

What Does the 500 kW Net Metering Cap Actually Mean?

Net metering allows rooftop solar owners to export surplus electricity to the grid and receive a credit — unit for unit — against their future bills. It has been the financial backbone of rooftop solar adoption across India, making payback periods shorter and projects more bankable for commercial and industrial (C&I) consumers. The BERC's proposed 500 kW ceiling means that any rooftop solar installation in Bihar with a sanctioned capacity beyond that mark will no longer qualify for this one-to-one offset arrangement. Instead, surplus generation above the cap would be compensated at a rate set by BERC — almost certainly lower than the retail tariff consumers currently enjoy. This is not an entirely new direction in Indian solar regulation. The Ministry of New and Renewable Energy (MNRE) and the Central Electricity Regulatory Commission (CERC) have both signalled in recent years that unlimited net metering may not be sustainable as grid-connected solar volumes grow. Several states, including Tamil Nadu and Andhra Pradesh, have already implemented tiered or capped net metering frameworks to manage reverse power flow and grid stability concerns, making Bihar's proposal part of a broader national pattern.

For Bihar's C&I consumers — factories, cold storage units, educational institutions, and large commercial complexes — a 500 kW cap is consequential. Many of these facilities have rooftop potential well above this threshold and have been planning solar investments on the assumption of full net metering benefits. The revised compensation rate for surplus power will directly affect project IRRs and payback calculations. Developers and EPCs bidding on C&I rooftop projects in Bihar will need to re-model their financial assumptions immediately.

How Will Bihar's Surplus Power Compensation Be Revised?

The second critical element of BERC's proposed amendments is the revision of the compensation mechanism for surplus electricity injected into the grid. While BERC has not yet finalised the exact rate, the direction is clear: surplus power will likely be compensated at the Average Power Purchase Cost (APPC) or a similarly benchmarked wholesale rate, which in Bihar's case is substantially below retail tariffs. This approach mirrors what regulators in Karnataka and Telangana have adopted, where the gap between retail tariff credits and APPC-level compensation can be as wide as ₹2–₹4 per unit — a difference that materially erodes the economics of large rooftop solar systems. The BERC amendment process will involve a public comment period, giving developers, industry bodies like the Solar Energy Corporation of India (SECI), and the National Solar Energy Federation of India (NSEFI) an opportunity to push back on rates that could stall rooftop deployment in the state. Bihar's power distribution companies — SBPDCL (South Bihar Power Distribution Company Ltd) and NBPDCL (North Bihar Power Distribution Company Ltd) — have a direct stake in the outcome. Both discoms have faced significant aggregate technical and commercial (AT&C) losses and are likely supportive of a framework that limits their financial exposure to high-credit net metering obligations.

The compensation rate finally adopted by BERC will function as a de facto floor price signal for rooftop solar in Bihar. If set too low, it risks choking the pipeline of C&I and large institutional rooftop projects — precisely the segment that requires the least government subsidy and delivers the fastest capacity addition. Stakeholders have an urgent window to engage with the BERC consultation process before these draft amendments are gazetted.

What This Means for India's Energy Transition

Bihar's proposed net metering cap arrives at a pivotal moment for India's distributed solar ambitions. The PM Surya Ghar: Muft Bijli Yojana scheme, launched in 2024 with a ₹75,000 crore outlay, is specifically designed to accelerate rooftop solar across Indian households and is exempt from net metering caps at the residential scale. However, the C&I rooftop segment — which contributes disproportionately to India's overall rooftop solar capacity additions — is not similarly insulated. India's installed rooftop solar capacity crossed 15 GW in 2024, with C&I consumers accounting for the majority of that base. Achieving the national 500 GW renewable energy target by 2030 requires rooftop solar to scale aggressively in every state, including those like Bihar that are still early in their distributed generation journey. Regulatory moves that compress the economics of large rooftop systems, without providing clear alternative incentives, risk slowing momentum in states where grid-scale solar land acquisition is also constrained.

Watch three developments closely over the coming months: BERC's final determination of the surplus power compensation rate, the volume and nature of industry responses during the public comment window, and whether MNRE issues any advisory to harmonise state-level net metering caps with national rooftop targets. Bihar's regulatory choices will serve as a reference point — or a cautionary tale — for other eastern and central Indian states still calibrating their own distributed solar frameworks.