•  Says all guidelines, sample docs issued to NSO ahead of March 2027 deadline 

The Public Utilities Commission of Sri Lanka (PUCSL) yesterday (31 August) said it had already issued all necessary guidelines and sample documents required for the implementation of the battery energy storage system (BESS) capacity to the National System Operator (Private) Limited (NSO), well in advance of the tariff decision requiring such implementation.

The PUCSL’s clarification comes in response to remarks made by the NSO’s Chairperson Dr Pradeep Perera, who told The Daily Morning that the NSO is unable to immediately implement the PUCSL directive to establish the BESS capacity for solar energy by next year (2027), citing a lack of detailed implementation agreements and documents.

Director of Corporate Communications at the PUCSL, Jayanath Herat told The Morning that the Commission had provided sample documents, including a draft declaration to be signed by a chartered engineer. He added that preparing final agreements and internal administrative documents, along with their speedy implementation, is the responsibility of the licensee, referring to the NSO.

The PUCSL issued the directive as part of its approved tariff decision, requiring the NSO to ensure that at least 450 megawatts of solar photovoltaic (SPV) capacity with the BESS is added to the electricity system by March 2027. This measure is intended to address a forecast capacity deficit in the first quarter of 2027 and ensure sufficient capacity to meet the peak demand without scheduled power interruptions.

Dr Perera had said that the NSO had only received the initial decision but lacked the practical guidelines required for execution, noting that the NSO had requested formal instructions and clarifications from the Energy Ministry. He said that while some baseline numbers had been provided for the BESS, concrete agreements and administrative documents needed finalisation before work could begin, adding that the NSO is not in a position to implement the directive immediately.

The documents seen by The Morning show that the PUCSL has issued key directives and approved regulatory guidelines to major power sector institutions on the implementation and operation of rooftop (RT) SPV and the BESS. According to the documents, the PUCSL issued a directive to Electricity Distribution Lanka (Pvt.) Ltd. (EDL) on 3 August, officially approving and directing all distribution licensees to comply with and enforce the newly established regulatory framework for the RTSPV and the BESS with effect from that date. The directive required compliance with the Standards Institution’s (SI) technical specifications for the BESS, the use of standard agreements alongside a newly introduced BESS integration addendum, adherence to interconnection guidelines for distribution utilities and prosumers, and the collection of a mandatory technical compliance declaration signed by a registered chartered electrical engineer upon the commissioning of every RTSPV/BESS installation. The letter was signed by Director General (DG) Damitha Kumarasinghe and Deputy DG – Industry Services Kanchana Siriwardena.

A separate directive was issued to the NSO on 4 August, sharing the approved regulatory framework for the RTSPV and the BESS for awareness, information and alignment within the NSO's grid operation mandate. This directive highlighted operational pillars including compliance of the BESS installations with SI technical specifications, system integration in line with interconnection guidelines, and the enforcement of the mandatory chartered electrical engineer declaration upon commissioning. This letter was signed by Siriwardena.

The documents also show that the PUCSL earlier directed the Ceylon Electricity Board, in a letter dated 11 June of last year (2025), to implement a revised contractual structure for RTS electricity generation, including standardised interconnection agreements, application forms and amendments to supply services codes, to facilitate investment.

The directives cite the Safety, Quality and Continuity of the Electricity Supply Regulations of 2016, the Sri Lanka Standard SLS 1680:2020 governing the safety of hybrid solar inverters, and BS 7671, the Institution of Engineering and Technology Wiring Regulations for electrical installations, as among the technical standards that licensees must follow. 

(MD)