Spain will quadruple the number of trading rounds in its continuous intraday market, from 24 to 96 , completing the adaptation of its electricity operations to 15-minute intervals and offering greater flexibility to adjust programs in response to variations in renewable generation.
The National Commission for Markets and Competition (CNMC) approved modifications to the Rules of Operation of the Daily and Intraday Electricity Markets and to the operating procedures PO3.1, PO7.2, PO9.1 and PO14.4.
With the new structure, producers, consumers, and storage systems will be able to adjust their positions every 15 minutes , instead of maintaining a logic based on time blocks. This will allow for a more precise response to changes in wind, solar radiation, or demand.
The expected result is a reduction in the difference between planned energy production and actual energy production or consumption. By decreasing these discrepancies, the need to activate reserves and other electrical system balancing services should also decrease.
The change deepens a transformation that began in 2025. Since the origins of the Spanish electricity market in 1998, trading had traditionally been structured in hourly periods.
The increasing penetration of renewable energy began to put that configuration under pressure. The variability of technologies such as solar photovoltaics and wind power made it increasingly difficult to represent real-world generation conditions, and by extension, the system's needs, using one-hour blocks.
In March 2025, the intraday market, including continuous trading, evolved into a quarter-hourly product . In October of the same year, that same scheme was implemented in the daily market.
However, one piece remained missing: although energy could be traded in 15-minute products, the continuous intraday market still maintained 24 rounds , inherited from the hourly schedule.
The reform approved by the CNMC seeks to eliminate that difference and also bring the number of rounds to the quarter-hour logic.
In this way, the market will have 96 trading opportunities throughout the day , allowing positions to be updated with a time granularity consistent with the products that are already being traded.
For a renewable energy plant, this possibility becomes especially important when the forecasts made in advance do not end up coinciding with the actual production.
An unexpected change in solar radiation or wind resource can alter the projected generation. The closer to real-time the schedule can be corrected, the smaller the deviation the system will subsequently have to manage.
The same logic applies to consumers and storage assets , who will be able to update their programs more frequently according to their operating conditions.
The quarter-hour jump multiplies the technological demands
Moving from 24 to 96 rounds also poses a challenge to the infrastructure that supports the market's operation.
The introduction of quarter-hourly products in 2025 had already quadrupled the volume of data that needed to be processed and exchanged . Now, the increase in the number of rounds again quadruples the processes associated with the continuous intraday market horizon.
In addition, part of this operation takes place just one hour away from the physical delivery of the energy , raising the demands on speed, coordination and information processing.
To support this increase, the regulation incorporates modifications to the type and scope of data exchanged, temporary adjustments to processes, and safeguards against potential failures.
The ultimate goal is that more precise scheduling by the agents themselves will reduce the subsequent interventions needed to keep the system balanced.
The reform also continues to bring the Spanish structure closer to the harmonization of the European electricity market operation , in a context where greater temporal granularity gains relevance as the participation of variable sources increases.
For solar and wind, the 96 funding rounds will offer more opportunities to adjust forecasts to actual generation. For storage systems, they will provide greater capacity to update their charging and discharging schedules in near real-time .
Spain thus completes another step in its transition from the historic hourly-based market to a quarter-hourly operation , with 96 rounds seeking to adapt electricity trading to a system where generation, consumption and storage conditions can change much faster than before.