The San Pedro II, located in the river Sil, will add approximately 25MW capacity to the existing 32MW facility, the company said.
During the construction phase, the hydroelectric project is anticipated to create around 190 direct jobs.
Meanwhile, the San Pedro hydroelectric plant acts as a reservoir for Santo Estevo, by controlling the Sil river flow.
Santo Estevo, with an installed capacity of around 441MW, generates 1,000GWh of enough clean energy annually to power around 285,000 homes.