GNA opens Brazil’s largest thermal power plant at Porto do Açu

The new facility, GNA II, has an installed capacity of 1,673 megawatts and was recently approved for operation by Brazil’s electricity regulator, ANEEL. Capable of supplying energy to roughly 8 million homes, the plant positions GNA as the operator of the largest natural gas-fired power complex in Latin America.

GNA II complements the company’s first plant, GNA I, which has been running since 2021 with a capacity of 1,338 MW. Together, the two units represent 17% of Brazil’s thermal generation capacity and play a crucial role during dry seasons when hydroelectric output declines.

The goal was to establish a gas hub at Porto do Açu, GNA CEO Emmanuel Delfosse told Valor. “These plants are like insurance for the power system as they come online when they’re most needed.”

The plants are connected to a private liquefied natural gas (LNG) regasification terminal with a daily capacity of 21 million cubic meters. This allows GNA to import LNG and convert it back to gas for power generation. Combined, the thermal units consume about 12 million cubic meters per day, roughly equivalent to the energy consumption of the entire state of São Paulo, according to Mr. Delfosse.

With GNA II operating under a 40% inflexibility clause, the system is contractually required to use the plant at least 40% of the time during Brazil’s dry season, from July to November.

The facility runs on natural gas and was contracted through Brazil’s energy auctions. It operates in a combined-cycle configuration, improving efficiency and lowering emissions. However, it lacks “fast ramp” capability, meaning it must be brought online several days in advance—a limitation in terms of operational flexibility.

GNA II is part of the federal government’s revamped Growth Acceleration Program (PAC), which targets key infrastructure investments. The total investment in the GNA power complex stands at R$12 billion. “It was a major technical and logistical challenge, especially during the pandemic,” Mr. Delfosse said. “Doing business in Brazil is complex. The scale of this industrial venture alone—R$12 billion—is remarkable.”

The project also has room for significant expansion, with 3.4 GW of additional capacity already authorized from an environmental standpoint. Any future development, however, will depend on demand in upcoming energy auctions.