Techno-economic assessment of converting a coal-fired power plant into a renewable solar power plant with thermal energy storage

This study evaluates the conversion of the Angamos coal-fired power plant in Chile into a renewable power plant through a techno-economic comparison of different energy configurations integrating solar generation and energy storage. The analyzed configurations include: a hybrid PV-parabolic trough plant with thermal energy storage (TES), a hybrid PV-solar tower plant with TES, a standalone CSP tower plant with TES, a PV plant with battery storage, and a Carnot battery coupled with PV, an electric heater, and TES. The operational strategy is a key factor in the assessment of these plants. Two main options were considered: baseload operation, aiming for continuous 24/7 production, and a storage-based strategy, in which electricity is only produced at night to compensate for the lack of renewable generation during these hours. The latter strategy was analyzed both with an on-site PV plant and with a hypothetical, grid connected PV plant assumed to supply any required amount of electricity at a fixed price. Scenarios of “Brownfield” (reusing the existing power block) and “Greenfield” (new build) were assessed. The results of the techno-economic analysis indicate that hybrid CSP-PV plants achieve costs similar to Carnot batteries and lower than conventional batteries for high nighttime capacity factors. Operating strategy and cost assumptions are decisive for the competitiveness of each alternative.