The West Bengal Electricity Regulatory Commission (WBERC) has issued draft regulations for grid-interactive rooftop solar systems. The regulations provide a detailed framework for installing, operating, and managing rooftop solar systems.

Stakeholders can send comments and suggestions on the draft by November 14, 2024.

The draft regulations permit consumers of any distribution licensee to install rooftop solar systems, with options for self-ownership or third-party ownership models.

To ensure grid stability and prevent oversizing, these systems’ maximum capacity is capped at 100% of the consumer’s sanctioned load or contract demand, whichever is lower.

This provision aims to strike a balance between encouraging solar adoption and maintaining the integrity of the distribution network.

The WBERC has proposed two metering mechanisms to accommodate different system sizes.

Net metering is proposed for systems up to 500 kW capacity, allowing prosumers to offset their energy consumption with solar generation. For systems above 500 kW, gross metering will be implemented, with separate accounting for energy injection and consumption.

The regulations mandate the installation of bi-directional meters to accurately measure electricity imports and exports and ensure fair and transparent energy accounting.

A detailed energy accounting and settlement mechanism has been introduced in the regulations. Energy generated from the rooftop solar system will primarily be used for self-consumption, with excess energy exported to the grid being credited to the prosumer’s account. Settlement periods are defined every month, with provisions for carrying forward excess energy to subsequent billing cycles.

An annual settlement will be conducted at the end of each financial year, with any remaining excess units being forfeited. This approach encourages efficient energy use and prevents the accumulation of large energy credits.

The WBERC has proposed differentiated tariff structures for various consumer categories to ensure fair compensation for solar energy generation. Domestic consumers with systems up to 500 kW will receive a tariff for net excess injection equal to the average power purchase cost of the respective distribution licensee.

Commercial and industrial prosumers will be subject to tariffs as determined by the Commission for the relevant year. Special provisions are also made for government buildings and institutions to promote solar adoption in the public sector.

The draft regulations emphasize technical standards and safety measures to ensure the reliability and safety of rooftop solar systems. The regulations mandate compliance with Central Electricity Authority regulations on technical standards for connectivity of distributed generation resources.

Installation of safety equipment such as manual disconnect switches and anti-islanding protection is mandatory. Regular maintenance and testing requirements are also specified to ensure ongoing system performance and safety.

The implementation framework outlined in the regulations includes a streamlined application process. Prosumers can submit applications online to the distribution licensee, who must conduct a technical feasibility assessment within 15 days of application receipt.

The licensee must communicate approval or rejection within 30 days of application, and the system must be commissioned within 180 days of approval.

This process aims to expedite the adoption of rooftop solar stems while ensuring proper vetting and implementation.

The regulations define the roles and responsibilities of both distribution licensees and prosumers. Distribution licensees are tasked with facilitating the interconnection process, conducting technical feasibility studies, and ensuring proper metering and billing.

Prosumers are responsible for system maintenance and compliance with safety standards, providing access for inspections and meter readings, and adhering to the terms of the interconnection agreement.

This clear delineation of responsibilities helps ensure the smooth operation and maintenance of the rooftop solar systems.

The regulations mandate compliance with specific technical standards to maintain grid stability and power quality. These include adherence to harmonic current injection limits as per IEEE 519-2014 standards, maintenance of power factor within the specified range of 0.95 lagging to 0.95 leading, and automatic disconnection of the rooftop solar system in case of grid failure.

In June, the WBERC proposed rules encompassing various provisions relating to the determination of tariffs in the state. The WBERC (Modalities of Tariff Determination) Regulations, 2023, intends to provide a transparent and structured framework for the state’s power generation, transmission, and distribution, ensuring fair and efficient consumer electricity pricing.

Subscribe to Mercom’s real-time Regulatory Updates to ensure you don’t miss any critical updates from the renewable industry.