Quick summary

Renewable generation has made electricity supply harder to predict, pushing more trading into intraday markets that clear close to delivery. The EU's move to 15-minute products and continuous cross-border trading sharply raises the data, speed and automation demands on energy trading and risk management systems. This article explains why intraday markets keep growing and what they now require of the software behind them.

Introduction

For decades, most electricity was bought and sold in day-ahead markets, where participants agreed quantities and prices the day before delivery. That model assumed generation was largely controllable. As wind and solar have grown, the assumption no longer holds, because their output depends on weather forecasts that only sharpen as delivery approaches, so positions fixed a day ahead are frequently wrong by the time power flows.

The response has been a steady shift towards intraday trading, where participants adjust their positions through the delivery day itself. For energy companies across Germany, the Nordics and the wider EU, this changes what their trading systems have to do. Energy trading and risk management (ETRM) platforms designed for a slower, day-ahead rhythm now have to run continuously, at finer time resolution, and with far more data.

Why intraday trading keeps growing

The driver is balancing. Once the day-ahead market closes, any gap between a participant's forecast and reality has to be closed somewhere, and intraday markets are where much of that happens. As intermittent generation rises, the value of trading close to delivery rises with it, because it lets participants correct forecast errors before they turn into costly imbalances.

The European single intraday coupling now links national markets so participants can trade continuously across borders right through the delivery day. Trading begins the day before delivery and continues into the delivery period, supporting real-time adjustments to supply and demand across the EU (ENTSO-E, 2024). The implication is that intraday is no longer a marginal venue for last-minute tweaks; it has become a core part of how European power is traded.

As renewables grow, the centre of gravity in power trading shifts from a single day-ahead decision towards a continuous stream of adjustments.

Takeaway: Intraday trading has become a primary market because renewable forecasts only firm up as delivery approaches.

The move to 15-minute products

Trading is also becoming more granular. Solar and wind output can change sharply within an hour, so hourly products struggle to reflect steep ramps in supply and demand. To address this, the EU has introduced 15-minute trading products across its coupled markets. ACER amended the day-ahead products methodology in 2024 and the intraday products methodology in 2025 to allow 15-minute intervals in both markets (ACER, 2025).

Timing is tightening too. Under the EU's electricity market design reform, the cross-zonal gate closure time, the last moment to match cross-border trades before delivery, is being reduced from 60 minutes to 30 minutes (ENTSO-E, 2024). The reason this matters is that finer granularity captures short-term volatility more accurately, but it also multiplies the number of tradable products, the volume of data each system handles, and the speed at which decisions must be made.

Every increase in market granularity is also an increase in the data and speed demands placed on the systems behind the trade.

Takeaway: 15-minute products track renewable volatility more closely, at the cost of far more data and tighter timing.

What continuous markets demand of ETRM systems

A platform built for day-ahead markets typically processes a manageable set of hourly positions once per day. Continuous intraday trading at 15-minute resolution is a different problem. Systems have to ingest live order books, update positions in near real time, and present an accurate view of exposure as it changes through the day.

Several capabilities become essential:

• Real-time position and profit-and-loss tracking across many short products
• Automated and algorithmic order placement, since manual trading cannot keep pace with continuous markets
• Integration with renewable generation and load forecasts that update through the day
• Low-latency connectivity to exchanges and coupling platforms
• Resilience, so an outage during delivery does not leave positions unmanaged

This is where energy expertise meets software engineering. The hard parts are rarely the trading rules themselves, they are the data pipelines, latency budgets and failure handling that let those rules run safely against live markets.

The competitive edge in intraday trading increasingly lies in the quality of the software and data infrastructure, not only in the trading strategy.

Takeaway: Continuous, granular markets turn ETRM from a daily batch process into a real-time operational system.

The compliance and data trail

Faster, more automated trading raises the regulatory stakes. Wholesale energy trading in the EU is governed by REMIT, the framework against market abuse, which requires participants to report transactions and orders to regulators. The 2024 revision, known as REMIT II, broadened that scope and tightened reporting as markets grew more complex and automated (European Commission, 2024).

For ETRM systems, the practical consequence is that every order and trade has to be captured, time-stamped and reportable, and that surveillance for potential manipulation has to keep pace with automated strategies. The reason this matters is that a system optimised only for speed, without a complete and auditable data trail, can create compliance exposure even when the trading itself is entirely legitimate.

Takeaway: In automated intraday markets, reporting and surveillance capability is part of the trading system, not a separate afterthought.

Building for continuous markets

The durable way to approach intraday capability is to treat the trading platform as real-time infrastructure. That means designing around streaming data, well-defined interfaces to market platforms, and a clear separation between trading logic, risk controls and reporting, so each can evolve as conditions change.

It also means planning for change. The EU continues to reform market timings, products and reporting, so systems that hard-code today's rules tend to age badly. Architectures that isolate market-specific detail behind stable interfaces adapt more cheaply as the rules move. For energy companies in Germany, the Nordics and Benelux, where intraday and balancing activity is most intense, that adaptability is becoming a competitive requirement rather than a refinement.

Intraday systems should be built to absorb regulatory and market change, because in European power markets that change is constant.

Takeaway: Treating the trading platform as adaptable real-time infrastructure is what keeps it viable as markets evolve.

Conclusion

The growth of renewables has reshaped how electricity is traded, moving volume and value into continuous intraday markets that clear at 15-minute resolution and ever closer to delivery. That shift rewards participants whose systems keep up and penalises those whose platforms were built for a slower era.

For energy companies operating across the EU, modern ETRM capability is now as much a software and data challenge as a trading one. The organisations that treat it that way, building adaptable, real-time and fully auditable systems, are the ones positioned to trade both profitably and compliantly as markets continue to change.

FAQ

What is an ETRM system?

ETRM stands for energy trading and risk management. An ETRM system is the software energy companies use to capture trades, track positions and exposure, manage risk, and support settlement and regulatory reporting across electricity, gas and related markets. As trading has moved towards continuous intraday markets, these systems increasingly need to operate in near real time rather than in daily cycles.

Why has intraday electricity trading grown so much?

The main driver is the rise of variable renewable generation. Wind and solar output depends on weather, and forecasts only become accurate as delivery approaches, so positions set in the day-ahead market often need correcting. Intraday markets let participants adjust closer to real time, which reduces imbalance costs and the reserves the system has to hold.

What are 15-minute trading products?

They are electricity contracts for delivery over a 15-minute period rather than a full hour. The EU has introduced them across its coupled day-ahead and intraday markets to better reflect the rapid ramps in renewable generation and demand. Finer granularity improves accuracy but significantly increases the number of products and the volume of data trading systems must process.

How does REMIT affect trading systems?

REMIT is the EU regulation that protects wholesale energy markets against manipulation and requires participants to report trades and orders. Its 2024 revision broadened the scope of covered products and participants and tightened reporting. In practice, trading systems must capture complete, time-stamped, reportable records of all activity and support surveillance that can keep pace with automated trading.

What makes continuous intraday trading hard for software?

Continuous markets require systems to process live order books, update positions and risk in near real time, and place orders automatically, often at 15-minute resolution across many products. The engineering challenges are data throughput, low latency, resilience during the delivery day, and integration with intraday forecasts, rather than the trading rules alone.

Sources

• ACER amends EU electricity single intraday coupling products methodology - ACER - 2025 - https://www.acer.europa.eu/news/acer-amends-eu-electricity-single-intraday-coupling-products-methodology-enhance-market
• Wholesale energy market integrity and transparency - European Commission - 2024 - https://energy.ec.europa.eu/topics/markets-and-consumers/wholesale-energy-market/wholesale-energy-market-integrity-and-transparency_en
• Single intraday coupling (SIDC) implementation - ENTSO-E - 2024 - https://www.entsoe.eu/network_codes/cacm/implementation/sidc/