Wholesale Electricity Market Normalization and Modernization

Resolution 400/2025 of the Secretariat of Energy (SE) was published in the Official Gazette on October 21, 2025, approving the Rules for the Normalization of the MEM and Its Progressive Adaptation. These rules—incorporated as Annex I of the Resolution—apply to the economic transactions of the wholesale electricity market (MEM) as of November 1, 2025.

Resolution 400 and the Rules are part of the electricity reform promoted by the federal government, which began with the enactment of the Bases Law in 2024. This reform aims to advance towards a competitive energy market. The new regulations govern various aspects related to fuel management, energy and capacity prices, the term market, reliability services, and charges within the electricity system.

The MEM’s normalization process is being carried out within the framework of a gradual transition that seeks to restore a marginal pricing scheme and strengthen private investment participation in the sector. Starting in November of 2025, prices will be freely set by supply and demand, and the Wholesale Electricity Market Administrator Company (CAMMESA) will remain as a regulatory entity without intervening in operations.

The Rules establish a price signaling system for electricity demand and a payment mechanism for electricity supply based on marginal costs, aimed at reflecting the real costs of MEM supply.

To comply with the Rules, Resolution 400 categorizes Stationary Demand by MEM Distribution Agents into two groups:

1. Large Distribution Users (GUDI): users with a demand equal to or greater than 300 kW.
2. stationary demand: residential and non-residential users.

Resolution 400 also redefines the classification of generation and establishes three categories, each with a differentiated remuneration scheme:

• Assigned Generation: this includes plants with contracts in force until their expiration (thermal and renewable) and under state control, including national hydroelectric, nuclear, binational generation, and energy imports made centrally by CAMMESA.
• Spot Generation: this includes plants not classified as Assigned Generation, which may participate in the Spot Market and the Term Market, except for thermal power plants of Energia Argentina SA (ENARSA) or those with majority state participation and combined cycle plants maintaining commitments under Resolution 59/23, which remain temporarily outside this regime.
• New Generation: this comprises plants with commercial authorization after January 1, 2025.

Some of the guidelines the Rules establish are:

• Stationary demand of MEM distributors: it was determined that such demand will be supplied with Assigned Generation and will be subject to stationary prices set by the SE.
• Decentralized fuel management: CAMMESA will cease to centralize the purchase of fuels and generation contracts. Thermal generators will manage production directly, being able to recover costs through the Spot Market or the Term Market, in a transitional scheme until January 1, 2029 (when the Gas Plan ends), at which point full management by generators will be mandatory. CAMMESA will retain its functions of market dispatch and settlement, as well as acting as a supplier of last resort for agents unable to secure supply.
• Spot demand (generator remuneration): energy and capacity prices applicable to demand not covered by contracts or included in Stationary Demand are specified. In the medium term, MEM energy and capacity prices will be determined based on marginal production costs.
• Term market: Resolution 400 reinstates the Term Market (MAT), which has been formally very limited since 2013 and affected in its regular operation since at least 2003. The implementation of a Term Energy Market (MATE) and a Term Capacity Market is foreseen, allowing free contracting between generators, distributors, and large users. Its operation will be equivalent to the Renewable Term Market (MATER).
• Expansion of generation supply: CAMMESA must assess generation capacity annually for the next three years and recommend the necessary incorporation of energy and capacity to ensure supply. In this context, the SE may organize tenders to secure medium-term supply.
• System charges: costs associated with services and transmission will be allocated proportionally to each agent’s monthly energy, regardless of contracts in the MAT.
• Non-centralized import and export of energy: import and export of energy are enabled through bilateral supply agreements between private parties.

Resolution 400 and the Rules drive a paradigm shift in the Argentine electricity sector: the federal government resumes its role as regulator, promoting clear rules, real prices, and freedom of contracting. With this structural reform, the government seeks to attract private investment, improve service quality, and ensure sustainable access.