Engie Brings a 116 MW / 660 MWh Battery Online at Chile's Former Tocopilla Coal Complex, Repurposing a Decommissioned Thermal Site for Grid Storage
Engie Chile's standalone Tocopilla battery, built where a coal complex once stood, reached commercial operation with 116 MW / 660 MWh of capacity.
Editor's Note ·
- Correction:
- The article states 'The system has a discharge duration of 5.7 hours, [ESS News] reported.' That 5.7-hour figure does not appear in the ESS News report or in either other cited source. It is consistent with the system's rated capacity (660 MWh divided by 116 MW is approximately 5.7 hours) but was not reported by ESS News and should not have been attributed to it.
- Correction:
- The article attributes the claim that this is 'the first large-scale standalone energy storage system Engie has built in the country' to ESS News. ESS News does not make that claim. The fact is correct and is supported by Engie's own release ('el primer sistema de almacenamiento standalone a gran escala de la compania en el pais') and by pv magazine Latin America ('el primer proyecto a gran escala de almacenamiento puro (stand-alone)'); the citation should point to those sources rather than to ESS News.
Overview
Engie Chile has brought a large standalone battery into commercial operation on the site of a decommissioned coal complex in northern Chile. According to ESS News, the company inaugurated the Tocopilla Energy Complex in Chile’s Antofagasta region, combining a 116 MW / 660 MWh battery energy storage system with flexible natural gas generation infrastructure and a synchronous condenser designed to provide stability services to Chile’s National Electric System (SEN).
The project entered commercial operation on February 19 after completing commissioning and regulatory validation, ESS News reported. The site is the former Tocopilla thermal complex, where the final coal-fired unit was disconnected in September 2022, according to both ESS News and Engie’s own commercial-operation announcement.
What We Know
The battery, known as BESS Tocopilla, comprises 240 lithium-ion battery containers, 30 power conversion systems, and a 130 MVA transformer connected directly to the transmission network, according to ESS News. Engie’s own announcement gives the same configuration of 240 lithium-ion battery containers, 30 power conversion systems, and a 130 MVA transformer. The system has a discharge duration of 5.7 hours, ESS News reported.
It is the first large-scale standalone energy storage system Engie has built in the country, meaning it is not directly tied to a specific generation facility but instead operates autonomously, charging and discharging according to the needs of the SEN, according to ESS News.
Engie says the battery will have an average annual generation capacity of 211 GWh, equivalent to supplying roughly 89,900 Chilean households, while avoiding the emission of 51,231 tonnes of carbon dioxide equivalent per year, according to its announcement. ESS News cites the same 211 GWh annual figure and the same 51,231-tonne emissions estimate.
Beyond the battery itself, the complex includes a synchronous condenser built by reusing infrastructure from the site’s former Unit 15, which Engie’s announcement describes as part of the site’s energy reconversion. Synchronous condensers supply inertia and voltage support to a grid that is increasingly served by inverter-based solar and wind, services that thermal plants traditionally provided.
The grid connection was completed in late 2025, with pv magazine Latin America reporting in November 2025 that Engie had fully connected the 116 MW / 660 MWh project, listing the same 240 battery containers and 30 power conversion units and the same estimated 211 GWh of annual discharge capacity. Engie had announced plans for the battery in April 2024, according to ESS News.
Juan Villavicencio, CEO and Managing Director of Renewables & Batteries at Engie Chile, framed the project as a pioneering effort that transforms a site historically associated with coal into infrastructure for Chile’s energy future, adding flexibility and stability to the electrical system and strengthening the security of supply, according to Engie’s announcement.
What We Don’t Know
Engie’s commercial-operation announcement does not state the project’s total investment, and figures cited by secondary outlets vary, so a confirmed capital cost is not established here. The announcements also do not detail how the battery’s revenue is split between energy arbitrage, capacity, and ancillary services on the SEN, nor the expected role of the co-located natural gas generation over time.
Analysis
The Tocopilla project illustrates a pattern increasingly visible in decarbonizing grids: reusing retired thermal sites, with their existing transmission interconnections and land, for storage and grid-stability assets rather than greenfield development. The pairing of a standalone battery with a synchronous condenser repurposed from a former generating unit, as described in Engie’s announcement, addresses a practical challenge of high-renewables grids, where retiring synchronous thermal generators removes inertia and voltage support that inverter-based plants do not inherently provide. With the final coal unit at the site already disconnected in September 2022, per ESS News, the commissioning marks the conversion of a long-running fossil site into a flexibility resource for Chile’s national grid.