The Spanish electricity market is undergoing a structural transformation that will change how energy prices are set. The shift from hourly intervals to 15-minute periods, known as the quarter-hour system, represents one of the most significant changes in the last decade for energy companies in Spain and, especially, for businesses managing their energy supply. If your company aims to optimize costs and improve energy planning, understanding this new model is essential.
Traditionally, Spain's wholesale electricity market has operated with hourly intervals (MTU60). This means electricity prices were set for each complete hour of the day, with a total of 24 daily prices. However, this model presents significant limitations in an increasingly dynamic energy context, dominated by intermittent renewable sources like solar and wind.
The quarter-hour system (MTU15) divides each hour into four 15-minute periods, generating 96 different prices throughout the day. This greater granularity allows for much more precise reflection of actual supply and demand fluctuations in the electrical system.
Red Eléctrica de España (REE) began settling deviations in 15-minute intervals from December 2024. Full implementation in the day-ahead market, managed by OMIE, was scheduled for September 30, 2025, with the first delivery day on October 1, 2025. This timeline ensured all market participants would be prepared for the transition.
This change responds to several strategic objectives of the European electrical system:
Until now, businesses were accustomed to relatively stable hourly prices, but with the new model, market dynamics become much more precise and, at the same time, more complex.
To understand this clearly, it's worth keeping three key elements in mind:
In the new system, the electricity price every 15 minutes is determined through the intersection of supply and demand curves for each interval. Producers submit their bids indicating at what price they're willing to sell energy in that specific period, while retailers and consumers communicate their purchasing needs.
The process is similar to the current hourly model, but with four times greater resolution. This granularity allows the system to capture real fluctuations much more accurately, such as unexpected demand spikes or rapid variations in renewable generation.
This level of detail also introduces an important effect: greater volatility. What was previously averaged over an hour can now change drastically every 15 minutes. For example, photovoltaic production at 10:00 AM can differ notably from 10:45 AM if cloud cover changes.
For organizations, this translates into a new challenge: managing costs with greater precision. But it also represents an opportunity, as they can take advantage of specific periods with lower prices and adapt their processes to benefit from them.
This transition also improves the integration of renewable energies into the market. By reflecting their variations more precisely, prices show more clearly when solar or wind energy is abundant—and therefore energy is cheaper—and when generation decreases, also affecting the price.
This will allow companies to design smarter consumption strategies, aligning their operations with moments when electricity is most competitive and sustainable.
For energy procurement managers, the quarter-hour system introduces a new dimension in planning. Electricity suppliers in Spain and their business clients will need to adapt to a much more dynamic and detailed pricing structure.
Cost forecasting becomes more complex, as small variations in consumption schedules can have significant impacts on the final bill.
For energy procurement managers, the quarter-hour system introduces a new dimension in planning. Electricity suppliers in Spain and their business clients will need to adapt to a much more dynamic and detailed pricing structure.
Cost forecasting becomes more complex, as small variations in consumption schedules can have significant impacts on the final bill.
The first step in adapting to the quarter-hour system is to thoroughly understand your company's consumption patterns. It's not enough to know how much electricity you consume per month; you need to begin identifying exactly when you consume it, with 15-minute precision.
The quarter-hour system is not just a technical change in how electricity prices are set; it represents a profound transformation in how companies must manage their energy. Businesses that understand this new context and proactively adapt their energy strategy as well as their consumption patterns will gain significant competitive advantages through cost control and operational optimization.
At Nordy, we understand the challenges companies face with the evolution of the electricity market. That's why we've developed solutions specifically designed to help organizations successfully navigate the transition to the quarter-hour system.
Turn market evolution into a competitive advantage for your business. Contact us for more information!