The Assam Electricity Regulatory Commission (AERC) has approved a ceiling tariff of ₹4.37 (~$0.049)/kWh for rooftop solar projects to be implemented on government buildings in Assam under the Renewable Energy Service Company (RESCO) model, as part of the PM Surya Ghar: Muft Bijli Yojana.

The order was issued in response to a petition filed by Assam Power Distribution Company (APDCL).

Background

APDCL sought approval for a ceiling tariff to select developers through a tariff-based competitive bidding process to install rooftop solar systems on government buildings.

In its petition, APDCL highlighted that the Ministry of New and Renewable Energy (MNRE) had notified a methodology for determining per-unit electricity charges for rooftop solar on government buildings.

Based on parameters such as capacity utilization factor (CUF) and cost inputs, APDCL proposed a ceiling tariff of ₹5.42 (~$0.061)/kWh, calculated at a CUF of 13.5%.

A slightly lower CUF of 13.04% yielded a tariff of ₹5.61 (~$0.063)/kWh. Accordingly, APDCL requested AERC to approve a ceiling tariff of ₹5.42 (~$0.061)/kWh, enabling bidding.

Under the PM Surya Ghar program, APDCL must ensure that all feasible government buildings, including those under the central and state administrative frameworks, as well as autonomous bodies and subordinate offices, are equipped with rooftop solar systems.

The developers will sell power directly to government buildings at a predetermined tariff, with excess electricity exported to the APDCL grid through an export-import metering arrangement.

Commission’s Analysis

The Commission noted that while the PM Surya Ghar program is an important step to enhance rooftop solar capacity, the ceiling tariff proposed by APDCL was on the higher side. It observed that the CUF considered in the petition, at 13.5%, was lower than the levels achieved by existing solar power generators in Assam.

AERC reviewed the tariff determination in line with MNRE’s methodology as well as its own AERC (Terms and Conditions for Tariff Determination from Renewable Energy Sources) Regulations, 2024.

The Commission relied on actual generation data provided by the state load dispatch center, which reflected higher CUF levels. Consequently, AERC decided to adopt a CUF of 16% for tariff calculations, along with a return of equity of 14%.

Applying these revised parameters, the Commission determined that a ceiling tariff of ₹4.37 (~$0.049)/kWh would be reasonable for initiating the bidding process under the RESCO model. It therefore directed APDCL to proceed with the competitive bidding for rooftop solar developers at the approved tariff level.

In April this year, AERC directed the APDCL to procure solar power at tariffs lower than ₹3.92 (~$0.046)/kWh.

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