The Energy Storage Systems (ESS) -hydro pumping stations and battery systems, for example- are becoming a realistic alternative to act in the wholesale markets as any other participant, i.e. generators, consumers or prosumers. The increasing interest in ESS for the grid can be due to multiple factors, amongst others, the progressive integration of renewable energy sources, the high capital costs of handling peak demands or the investments required for the improvement of the grid reliability. This article poses a model to calculate the revenue streams of ESS (batteries) in the Mexican electricity pool market. The model considers revenues from energy trading as a result of buying energy at a low price and selling it at a higher price acting in a day-ahead market (DAM). Another revenue stream could come from selling capacity or ancillary services, but this type of revenue is not (De la introducción)