Iberdrola Generación México, S.A. de C.V., a subsidiary of Iberdrola Mexico which belongs to Spanish holding Iberdrola, is engaged in the generation, transmission, transformation and disposal of electrical energy in Mexico. The company is the country's largest private energy producer with over 6,000MW in operation. The Mexico City-based company has been in the country since 1999. In March 2017, the company won the tender for the construction, operation and maintenance of the 766MW Topolobampo III combined cycle thermoelectric plant in Mexico's Sinaloa state. The company is also building the 887MW Topolobampo II and Escobedo combined cycle plants in Sinaloa and Nuevo León states respectively; the San Juan del Rio and Altamira cogeneration plants; the 220MW Pier and 105MW Santiago wind farms in Puebla and Guanajuato states respectively; and the 100MW Hermosillo and 170MW Santiago photovoltaic plants in Sonora and San Luís Potosí states respectively.