Thinner slices: Europe shifts to 15-minute power trading

Europe is striving for more renewables amid rising electrification, power supply and rapidly changing demand. To reflect these shifts, the European day-ahead market is getting more granular. On 1 October, price intervals will move from one hour to 15 minutes. Think of it like pizza – cutting it into more slices doesn’t just suit appetites better, it changes the whole experience for everyone at the table. Let’s look at what this means for market participants and why it matters as electrification and renewables reshape the energy landscape.

More “pizza” for all

With hourly prices, you get less control over the size of your portion – maybe it’s a bit too much or not quite enough. Cut the pizza into 15-minute slices and you can better match your appetite. Similarly, the new market will more closely match generation to demand, reflecting real system needs quarter by quarter.

This shift to 15-minute granularity will impact all actors. Europe’s single day-ahead coupling market spans the continent. It is by far the largest wholesale short-term market with huge volumes traded every day. Until now, markets cleared at hourly granularity – one price for each of the day’s 24 hours. Going forward: 15-minute intervals and 96 price intervals per day.

To understand this market change, let’s imagine you’re sharing a pizza. If it’s cut into four slices, you can only eat in large chunks – two or three slices, which might not match your appetite. But if the pizza is cut into eight slices, you can eat exactly five, fitting your hunger much better. The more slices the pizza has, the more precisely it suits what you need – just like the new 15-minute market intervals will better match supply and demand throughout the day.

Too many olives?

So how will this market change affect different players? Imagine olives and basil scattered over the pizza. When the slices are big, you get a bit of both toppings, which averages out the flavours. That’s how hourly prices have worked until now: they smoothed out the highs and lows. But with smaller slices, some pieces are heavy on olives, others have only basil, making the flavours more concentrated. With 15-minute trading, you’ll notice sharper bursts of “flavour” in prices across the day. This means greater price variation, as shown in the chart below. So depending on your role in the market, you’ll need to adapt your strategy to make the most of these new patterns.

Today’s market price trends will get sharper. Morning and evening ramps – when demand and solar output shift quickly – will get more dramatic, especially during summer. For example, the last quarter of some mornings may see cheaper prices as solar surges, while the reverse holds for evenings as solar fades. 

More frequent and sharper price spreads throughout the day could give a boost to flexible assets such as batteries. These additional price fluctuations bring new opportunities to trade the spread – charging when prices are low and discharging when they spike – ultimately increasing the potential for higher revenues. 
This is shown in the next chart.

Between September 2024 and September 2025, the 15-minute market delivered higher spreads 96% of the time. The maximum spread in the 15-minute market was EUR 1,335/MWh, compared with EUR 829/MWh in the hourly market – creating more “bites” to profit from daily volatility.  

Flexible consumers who can adjust their usage to cheaper 15-minute periods will have more ways to “build their perfect slice” and cut electricity bills. 

The cannoli problem 

After pizza it’s time for dessert. You want to buy two cannoli but they’re only sold in boxes of four for EUR 10. Even if you have EUR 5, you can’t buy two or even one because they’re only sold by the box. This is similar to the challenge with block orders in the power market – some market participants need to buy or sell electricity in larger blocks that don’t always fit neatly into the new, more granular 15-minute trading intervals. 

As the market shifts to these smaller time slices, managing block orders becomes more complicated. This increases the chances of “paradoxically rejected bids” – situations where a market participant should, in theory, be able to buy or sell based on price and available budget, but the structure of their block order doesn’t match the market clearing, so the order is rejected. In effect, you have enough money for dessert, but walk away empty-handed because the rules don’t allow partial purchases. As 15-minute trading becomes the norm, navigating block orders and avoiding these paradoxical rejections will be a growing challenge. 

There are other potential challenges of moving to 15-minute trading windows, including: 

• Increased volatility: More granular time intervals can lead to sharper and more frequent price swings, creating a less predictable market environment. 

• Higher risk of price spikes: Shorter pricing periods may amplify sudden changes in demand or supply, leading to brief but extreme price events – especially during unexpected outages or rapid changes in renewable output. 

• Market complexity: With more frequent settlement periods, market participants, especially smaller players, may find it harder to manage bidding strategies and risk. 

As these changes take effect, market participants will need to adapt, investing in better forecasting, real-time analytics and risk management tools to stay ahead in a landscape that now changes every quarter hour. 

Ripple effect  

The move to more granularity in day-ahead trading will ripple through subsequent markets. Initially, increased granularity should reduce corrections in the intraday and balancing markets. But participants with complex positions – like block orders – may see more corrections in the intraday market. So we should expect heightened volatility until these trading shifts and new flow patterns settle. 

Shifting from hourly to 15-minute prices in Europe’s day-ahead market brings the energy menu closer to reality – matching appetite with what’s actually on the plate. In this new regime, better forecasts and sharper strategies become crucial. For generators, traders and consumers alike, it’s time to get ready for more slices – and smarter bites – out of the market. 

This article originally appeared as a column on montelnews.com