Constrained-off and the infrastructure challenge
The significant growth of renewable sources in Brazil, especially wind and solar, is a concrete evidence of the progress of the energy transition in the country, which has one of the cleanest energy matrices in the world. However, the Brazilian electricity sector currently faces a structural challenge that needs to be addressed with attention: the limitations of the transmission infrastructure. This bottleneck, often invisible to those who only follow the announcements of new generation parks, has caused significant losses for energy producers, who have been bearing the risks and consequences of diminished generation due to being constrained-off.
The constrained-off occurs when energy production is reduced or interrupted not due to technical issues at the plant, reduction in consumption, or natural variations of the energy resource, but due to external restrictions on the generating plant, such as limitations in the transmission network or unavailability of equipment. In other words, even with favorable conditions to generate energy, the project is prevented from supplying it to the system. The phenomenon, which was already observed in specific cases, gained relevance as the volume of new plants exceeded the available energy transport capacity.
In the Brazilian scenario, the speed of expansion of renewable generation, especially in the Northeast, has not been matched by the same agility in constructing transmission lines or localized reinforcements for synchronous stability control. The direct consequence is the increase in constrained-off episodes, which penalizes generators, preventing them from marketing the energy produced, and indirectly affects consumers, who bear additional systemic costs.
Recently, the discussion about constrained-off has gained new momentum with the opening of public consultations at the National Electric Energy Agency (Aneel) and with judicial debates over the compensation rules for affected generators. The judicialization of the issue is symptomatic: it reveals that the current regulatory framework still does not provide complete answers to the effects of these restrictions in an increasingly complex and decentralized system.
However, the solution to the constrained-off issue is not limited to regulatory revisions or the definition of compensation mechanisms. The crux of the matter is structural: it is necessary to invest in a planned and continuous manner in the expansion and modernization of transmission networks. The recent addition of new lines to the National Interconnected System, such as those that increased the flow of energy from the Northeast to other regions, is a positive example, but still insufficient in light of the scale of renewable growth in the country.
Companies operating across the entire energy transition chain clearly see the need for the strengthening of the electrical infrastructure to keep pace with the expansion of generation. Without this, the country risks compromising both the competitiveness of the sector and its progress towards a cleaner and safer energy matrix.
The debate around constrained-off brings an important opportunity: to rethink the national energy planning in an integrated manner, that is, to plan electrical and energy expansion in a conjunctural and structural way. Overcoming this challenge requires a long-term vision that considers the complementarity between new energy sources and the real capacity of the system to absorb this generation.
Investing in transmission lines and appropriate supporting infrastructures (for example, synchronous compensators), planned from the outset of generation projects, is a necessary measure to ensure that Brazil continues to progress in its energy transition in a balanced and safe manner.
