The international competitive bidding process for the establishment of a 250 MW/1,000 MWh standalone Battery Energy Storage System (BESS) is to close within the first week of September, with the deadline having been extended by three weeks, the National System Operator (NSO) has stated.
The BESS procurement tender was launched by the NSO in mid-July this year. According to the NSO, it is part of an initiative to stabilise the growth of renewable energy.
However, although the submissions for tenders were to close by 14 August, the project’s Addendum No. 1 issued by the Ministry of Energy on 7 August extended the deadline to 4 September, with the Request for Proposal document being available until 3 September.
When contacted by The Sunday Morning, NSO Chairman Dr. Pradeep Perera noted that once the tender closed in September, it would be awarded to the relevant bidder in October. “The BESS will be connected to the system around April 2027,” he stated.
Additionally, he noted that the large-scale battery storage facilities were to be established outstation and not within Colombo. “These will be found by the developers themselves; they do not require very large lands. Typically, only a land area of about 50 perches is needed for batteries, unlike for solar,” Dr. Perera said.
As stated in the addendum, the land for the project is to be located within a maximum distance of 5 km from the designated grid substation.
This initial utility-scale standalone BESS procurement round kicked off in late 2025, according to Dr. Perera, to curb expensive evening peak fossil fuel generation and expand grid capacity. Initial tenders for the 160 MW/640 MWh procurement were invited on 30 July 2025, yielding 153 bids for 16 grid substations.
“The first one of those substations will be commissioned soon,” he said. “The remaining ones will all be commissioned around September or early October. Through that, we will integrate 16 batteries – which is 160 MW – into the system.”
He added that the active procurement of 250 MW was expected in April next year and that a total of around 560 MW was expected to be added to the system by that time.