ONS proposes recalibrating battery charges, focusing on power delivery during critical moments of the electrical system.
The debate over how to finance the future of energy storage is entering a new chapter. The National Electric System Operator (ONS) has submitted a suggestion to the National Electric Energy Agency (Aneel) that could significantly impact how the costs of future capacity reserve auctions, especially those focused on batteries, will be distributed.
The proposal aims to adjust charges for generators by tying them directly to their ability to supply power during periods of highest demand and need for the National Interconnected System (SIN).
The ONS initiative comes at a crucial time, with two major storage auctions scheduled for December.
The core idea is to replace the “Flexibility Index” considered by Aneel‘s technical staff with a “Critical Window Power Contribution Index” (ICP-JC).
The premise is simple: if what is being contracted is power availability, the cost should reflect how much each power plant contributes to ensuring that delivery during the most sensitive moments.
A New Cost Allocation Criterion
The ONS proposal suggests a change in the cost-sharing criterion for the Capacity Reserve Charge associated with storage systems (Ercap-SAE).
Currently, the methodology under discussion at Aneel provides for the participation of all generators in cost-sharing, with differentiated values across four tiers, ranging from 100% to 25% contribution.
The way this flexibility is measured varies by source: hydroelectric plants would have their generation compared between demand windows, while thermoelectric plants would consider start-up times and modulation.
However, ONS simulations indicate that the new approach would recognize the contribution of plants such as inflexible thermal and nuclear plants more accurately.
These plants, which operate continuously, could see their charges reduced, as their ability to deliver power at “peak” hours is a constant reality.
In contrast, solar plants without storage systems would maintain their full coefficient due to their intermittent nature and lower contribution during nighttime hours.
The Timing of the Proposal
The discussion gains urgency with the proximity of auctions scheduled for December 2 and 4.
The ONS suggestion was presented in a meeting with the office of Director Gentil Nogueira, the proceeding’s rapporteur, on September 14.
The expectation is that the regulation will undergo public consultation and deliberation by the Aneel board, with estimated timeframes of 30 days for consultation and another 30 days to consolidate contributions.
ONS also suggests that the methodology be calibrated jointly with the Energy Research Office (EPE).
The change proposed by ONS, if adopted, would bring a new dynamic to the sector.
By prioritizing the effective delivery of power during peak moments, the cost-sharing system aligns more directly with the service contracted from storage systems.
This change could encourage investments in technologies that ensure the reliability and stability of the SIN, especially in a scenario of growing participation from intermittent sources.
The final outcome of Aneel‘s decision will define the contours of how the country will advance in expanding its energy storage capacity.
