The National Electric Energy Agency (ANEEL) approved the regulation of Energy Storage Systems (ESS), closing the second phase of Public Consultation No. 39/2023, which received 652 contributions from 70 participants.
The decision consolidated important regulatory definitions related to the concession regime, the models for operating the activity, the remuneration of assets, the stacking of revenues (revenue stacking) and the rationalization of access contracts to transmission and distribution systems.
The main point of debate involved the form of charging for the use of the network. In this regard, the understanding presented in the opinion of Director Willamy Frota prevailed, which established a different treatment for autonomous SAEs fully controlled by the National Electric System Operator (ONS).
According to the approved solution, the systems that choose to be fully dispatched by the ONS will be able to contract only the Amount of Use of the Transmission System referring to the injection of energy (MUSTg), being exempt from contracting the amount of consumption (MUSTc-C). In these cases, the ONS will be responsible for fully determining the charging and discharging times of the batteries, in order to optimize the operation of the electrical system and avoid additional impacts on the grid.
As a consequence, the charges for the use of the network will be calculated exclusively on the generation portion, preserving the locational signal of the transmission and, at the same time, without compromising the collection of the transmitting concessionaires.
On the other hand, storage systems that operate freely, without centralized dispatch by the ONS, will remain subject to the current rules of contracting and payment for the use of the network, including the obligations associated with energy consumption for battery charging.
ANEEL highlighted that the solution adopted is in line with the guidelines that have been discussed by the Ministry of Mines and Energy (MME) for future storage auctions, in which the ONS should play a central role in the operational coordination of the projects.
In addition, the decision assigns new responsibilities to the ONS, which must annually publish maps with the best connection points for the installation of storage systems and present, within 180 days, proposals for updating the Network Procedures to incorporate the new regulatory rules.
The regulation represents a milestone for the development of the Brazilian energy storage market, providing greater legal certainty to investors and establishing the necessary regulatory foundations for battery systems to contribute to the operational flexibility of the SIN, the integration of renewable sources, the reduction of thermoelectric dispatch and the increase in the reliability of the national electricity system.
