The Department of Mineral Resources and Energy (DMRE) has postponed the bid submission date for the public procurement of battery energy storage systems (BESS) from July 5 to August 2.

The postponement was confirmed on June 27, along with confirmation that compulsory bid registration, including the payment of a registration fee, had been extended to July 7.

Engineering News understands that the extension is in response to several requests from prospective bidders related to Eskom's schedule for the issuance of cost estimate letters (CELs) for grid connections.

Eskom paused the issuance of such letters in a bid to revamp its grid-access rules, which have now been published, and the utility plans to issue outstanding CELs in July.

The BESS request for proposals (RFP) was launched on March 7 and the postponement follows on from difficulties with the three most recent public procurement rounds.

Very few projects from the risk-mitigation and the fifth bid window of the renewables programme have reached financial close, while none of the wind projects that bid during the sixth bid window advanced as a result of grid constraints.

Through the battery RFP, the DMRE is seeking to procure BESS projects with a combined capacity of 513 MW and a minimum of four hours of storage, or at least 2 052 MWh.

The batteries are set to be installed in close proximity to five substation sites in the Northern Cape, which have been specified by Eskom.

It is unclear what the postponement will mean for future public procurement rounds, with Mineral Resources and Energy Minister Gwede Mantashe having outlined, in May, a busy schedule for the remaining fiscal year to end March, including a plan to procure another 1 230 MW of battery storage in two rounds.

However, the DMRE has indicted that it is planning to recover lost time during the evaluation process.