The 15-Minute Market Revolution: What Hydropower Operators Need to Know

The European power sector is in the midst of a pivotal shift: trading intervals are moving from hourly blocks to 15-minute slices, bringing new opportunities for operators who can adapt quickly. While intraday markets in many regions are already running with 15-minute granularity, day-ahead markets will soon follow, albeit with a slightly delayed timeline. For hydropower operators, these changes promise more precise price signals, more efficient plant optimization – and, yes, more complexity. But don’t worry: HYDROGRID has you covered. Our platform has been 15-minute-ready from the start, ensuring you can make the most of every quarter-hour opportunity.

Below, we summarize the latest on the 15-minute switch, highlight the new go-live date for Europe’s day-ahead auctions, and explain how HYDROGRID helps you stay ahead of the curve:

• 15-Minute Resolution: Why It’s Happening
• Intraday: Where 15-Minute Trading Has Already Arrived
• Day-Ahead: The Revised Go-Live Date (30 September 2025)
• What It Means for Hydropower Operators
• Steps for a Smooth Transition – And a Brighter Future
• HYDROGRID: Ready For Every 15 Minutes (And Beyond)
• HYDROGRID Users - Ready to Embrace the 15-Minute Opportunity?

15-Minute Resolution: Why It’s Happening

The big driver behind 15-minute intervals is EU-wide harmonization. Since the standard imbalance settlement period (ISP) in Europe is 15 minutes, markets need to match that settlement period in both intraday and day-ahead timeframes. That means no more hour-long blocks for energy trading; instead, you’ll schedule or trade power in four discrete quarter-hour slots.

This greater granularity delivers several benefits:

• Improved accuracy: By shifting from hourly to 15-minute intervals, operators can refine forecasts and adjust output more frequently, potentially reducing large imbalances over time - even though each forecast run requires more data handling. In other words, while the number of decisions goes up, the shorter lead times can help minimize major swings between planned and actual production, resulting in smoother overall operations.
• Better renewables integration: Wind or solar can change fast; quarter-hour blocks capture those swings and let operators (like hydropower) respond accordingly.
• Potential for higher volatility (and revenue): More granular intervals often bring more frequent price swings—an opportunity for flexible plants to ramp up or hold back at precisely the right moments.
• The increased granularity ensures more grid stability by incentivising consistent production throughout the hour.

Intraday: Where 15-Minute Trading Has Already Arrived

Intraday markets led the change. In many European regions, 15-minute intervals are already live:

• Some countries (e.g., Germany, Austria) introduced 15-minute intraday products years ago on local exchanges.
• More recently, the pan-European “Single Intraday Coupling” (SIDC) project expanded 15-minute intervals to nearly all EU markets by early-to-mid 2025.
• While a couple of exceptions and slight delays remain (e.g., Greece), as of mid-2025, most intraday trading in Europe is conducted in 15-minute blocks.

For hydropower operators, this intraday transition means you can optimize generation—and react to real-time prices on a quarter-hourly basis. It’s a big step forward in capturing short-lived price peaks or avoiding dips. Luckily, if you’ve been using HYDROGRID, you’re already prepared to handle these finer intervals.

Day-Ahead: The Revised Go-Live Date (30 September 2025)

Initially, Europe’s day-ahead power auctions were set to embrace 15-minute time units by mid-2025. However, the official go-live was recently postponed by the Market Coupling Steering Committee (MCSC)—the joint body of power exchanges (NEMOs) and system operators (TSOs).

New timeline:

• The first day of trading with 15-minute products for day-ahead markets will be 30 September 2025.
• That means delivery starts on 1 October 2025 under the new quarter-hour resolution.

Why the delay? In short, additional testing was needed to ensure stability and avoid the risk of “decoupling” events, where the coupled auction might fail to produce a single set of results. The complexity of running day-ahead auctions in quarter-hour increments is far greater than running hourly blocks, so stakeholders chose to take extra time to perfect the process and ensure a smooth launch.

By 30 September 2025, expect the entire European day-ahead market covering almost all bidding zones from Iberia to the Nordics to move simultaneously to 15-minute resolution. There’s no partial rollout; everyone flips the switch at once.

What It Means for Hydropower Operators

1. Four Times the Price Signals: With 15-minute intervals, you’ll have four price points per hour instead of one. This higher frequency allows you to better time your generation output to match demand spikes or avoid price troughs.‍
2. Reduction in Imbalance Costs: Keeping your production in line with actual schedules is easier in 15-minute blocks—meaning fewer errors (and lower costs) when you settle your imbalances. With hydropower’s flexibility, you can quickly ramp to mitigate even short-lived deviations.‍
3. Need for More Advanced Tools: Handling four times the data requires robust software that can import prices, forecast production, and optimize dispatch automatically. Manual scheduling can become overwhelming, so it’s crucial to rely on intelligent solutions that do the heavy lifting.‍
4. Opportunities in Volatility: More granular intervals typically see more price volatility- great news for flexible hydropower. By responding quickly to quarter-hourly price swings, you can capture additional revenue that would be missed if you were only looking at hourly averages.

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A Smooth Transition – And a Brighter Future

While these changes may feel like a lot at once, the 15-minute market is actually a positive leap forward. It aligns Europe’s most important power trading platforms with modern realities, from renewables integration to short-term flexibility markets. Thanks to this refined granularity, hydropower operators stand to gain more precise control and new revenue streams—all while helping the grid handle fluctuating demand and supply.

For hydropower producers there may be multiple aspects of the IT landscape that need to be ‘ready’ for this switch, such as: your production planning system, your SCADA system, your power market access and trading platforms and likely your grid nomination processes.

Your production planning system will need to be able to:

• store power plant data and power prices in 15-minute granularity
• generate (optimal) production plans in 15-minute granularity
• If you use flexible, price-dependent power market bids (i.e. so-called ‘limit order bids’), your production planning system will also need to be able to generate bids in 15-minute granularity as well as calculate the correct execution of these bids in 15-minute granularity.

Your SCADA system will need to be able to: send and receive as well as execute generation plans in 15-minutes granularity.
Power Market Access & Trading: If you use an external power market access agent, ensure that your service provider is also ready to receive bids and plans in 15-minute granularity.
Grid Nomination: You may also need to adapt your protocol/interface for sending your planned production to your grid operator to 15-minute granularity.

Ready For Every 15 Minutes (And Beyond)

At HYDROGRID, we’ve been preparing for this moment. Our platform is ready now, so you can embrace 15-minute trading without a hitch. Whether you’re already seeing 15-minute intraday prices or gearing up for the day-ahead switch in September 2025, we have the tools and expertise to ensure a smooth transition.

We built our platform with future-proof flexibility in mind. Key features include:

• Seamless 15-Minute Price Imports: Our Price Importer directly integrates with power exchanges to pull in quarter-hourly price data, so you have an accurate feed for both intraday and day-ahead trading.
• Automated Scheduling & Bidding: We take the guesswork out of deciding when to generate. Our algorithms identify the most profitable timeslots and ensure your bids or schedules align with the latest market changes.
• Expert Support: Market transitions can be overwhelming, but you’re not alone. Our team has deep experience guiding operators through regulatory shifts, from hourly to quarter-hourly trading. We’ll keep you updated on every detail, and help you fine-tune your strategy to maximize revenues.

If you’re not yet a HYDROGRID user but are eager to stay one step ahead in the 15-minute market, get in touch with our team today. We’ll show you exactly how HYDROGRID can optimize your plant operations and future-proof your trading strategies for this next chapter in Europe’s energy evolution.

HYDROGRID Users - Ready to Embrace the 15-Minute Opportunity?

For existing users of HYDROGRID, the most important parts of the transition are already taken care of. We can even up-sample your historical, hourly data for you at the press of a button. We suggest that you get in touch with our Operations support team to discuss your switch:

• Coordinate when we switch your plant to 15 minute granularity within HYDROGRID to stay well ahead of the deadline.
• Ensure that any third party software products or services you use (e.g. your power market access or your SCADA system) is also ready for the switch.
• If your SCADA system is not (yet) configured to operate at 15-minute granularity, and you use HYDROGRID Insight, you can also continue sending and receiving your production plans to your SCADA system in hourly granularity in the interim via our API. Keep in mind that if you use flexible bidding but your SCADA system cannot execute a quarter-hourly plan, you may be generating some amount of imbalance penalties.

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