Brazil’s electricity sector has undergone unprecedented transformation in recent decades. Once dominated by hydropower plants with large reservoirs, the energy matrix is now shifting toward a diversified mix of sources, with natural gas thermal power plants emerging as key players in ensuring system security and flexibility. This article examines the role of these plants in Brazil’s energy transition, considering recent data and regulatory advances in the sector.
Natural Gas Thermal Plants: Historical Context and New Challenges
Throughout much of the 20th century and early 2000s, Brazil’s energy matrix was sustained by hydropower plants with large reservoirs capable of storing enough energy to meet the average consumption of the National Interconnected System (SIN) for months. This model provided robust energy security, allowing sector planning to focus almost exclusively on expanding energy generation to meet growing demand.
However, environmental and social constraints in the 2000s limited the construction of new hydropower plants with large reservoirs. Consequently, the SIN’s storage capacity remained practically stable despite a significant increase in energy consumption. This situation introduced a new challenge for Brazil’s electricity system: in addition to meeting the average annual demand, it became necessary to address fluctuations in peak demand.
In response, the National Energy Policy Council (CNPE) established the capacity supply guarantee criterion through Resolution 29/2019. Later, in 2021, the first Capacity Reserve Auction was held, a regulatory milestone that contracted additional capacity for the SIN, adapting the system to new sector demands.
The Expansion of Renewable Sources and Flexibility Challenges
Simultaneously, Brazil has witnessed rapid growth in renewable energy sources such as solar and wind. According to recent data, by September 2024, these sources accounted for 80 GW of installed capacity, with 60 GW added in the last five years. While these technologies contribute to decarbonizing the energy matrix, their intermittency poses significant operational challenges.
Daily variations in energy generation from these sources are substantial: wind generation, for example, can fluctuate by around 20 GW in a single day, while solar generation may experience variations exceeding 50 GW. This variability alters the net load profile of the SIN, requiring greater system flexibility to maintain stability.
Historically, hydropower plants have provided this flexibility, meeting intraday demand fluctuations. However, since mid-2023, it has become necessary to complement this flexibility with fast-mobilization thermal power plants. These plants operate between 2 to 8 hours daily, filling the gaps left by renewable sources.
Natural Gas Thermal Plants and a Just Energy Transition
Natural gas thermal power plants have proven essential to Brazil’s electricity system. Their fast activation capacity makes them ideal for meeting intraday demand and system emergencies. Examples like Karpowership’s floating power plants in Baía de Sepetiba illustrate this role. Over 12 months, these plants were activated more than 100 times, providing adequacy, security, and resilience to the SIN.
Recognizing their importance, the Ministry of Mines and Energy (MME) published Normative Ordinance MME 88/2024, creating economic incentives to increase SIN flexibility. Additionally, recent guidelines for the 2025 Capacity Reserve Auction include stricter technical requirements, such as faster ramps for new thermal power plants, reinforcing their role in the system.
A Sustainable Energy Transition
Natural gas is often seen as a transitional source due to its lower emissions compared to other thermal sources such as coal and oil. However, its role goes beyond that. Natural gas thermal power plants not only fill the gaps left by renewable sources but also ensure that Brazil achieves a just energy transition, balancing security, affordability, and sustainability.
With the ability to operate continuously when necessary and be quickly activated to meet system fluctuations, these plants play a crucial role in the stability and resilience of the SIN. Furthermore, their integration into the electricity system stimulates the growth of renewable sources, ensuring that the energy transition does not compromise the security of energy supply.
Brazil is at a decisive moment in its energy journey. The transformations in the SIN, driven by the expansion of renewable sources and regulatory advances, demonstrate the complexity of balancing sustainability, security, and affordability in a modern electricity system. In this scenario, natural gas thermal power plants emerge as protagonists, ensuring system stability while paving the way for a more diverse and cleaner energy matrix.
It is essential for decision-makers and society to recognize the strategic role of these plants in the energy transition. By ensuring that energy continues to flow reliably and sustainably, Brazil will be better prepared to face future challenges and consolidate its position as a leader in renewable energy in Latin America.
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