Chilean power transmission infrastructure operator Transelec has announced a partnership with energy firm Copec to develop a 105-megawatt (MW) battery energy storage system (BESS) in the Tarapaca region of northern Chile. The project will be co-located with the 123-MW Granja Solar plant, which Copec acquired in April from its bankrupt owner.
This marks the partners' first large-scale BESS initiative, which will be executed under a build, own, operate, and transfer (BOOT) contract. Under the agreement, Transelec will operate and manage the storage system for 20 years before transferring ownership to Copec.
The BESS will feature a storage capacity of 420 megawatt-hours (MWh) and will be integrated into the solar farm's substation via a 33-kilovolt (kV) transmission line. It will also connect to an existing 220-kV line leading to the Lagunas substation, owned by Transelec.
The batteries are expected to become operational in the first quarter of 2026. Copec Emoac, Copec's retail arm, will manage the sale of both the solar power generated by Granja Solar and the stored electricity from the BESS.
Transelec noted that the BESS will store daytime output from Granja Solar and release it at night, aiming to address Chile's significant increase in renewables curtailment, which has surged by 225% since 2021.
