What is intraday trading?

The intraday market is part of the spot market of the European Power Exchange (EPEX SPOT). Market participants trade electricity there on a short-term basis—intraday—and for the following day on the day-ahead market. Since October 2025, traders have also been using quarter-hourly contracts there in order to respond even more flexibly to the market.

In addition to the stock exchange, there is also OTC (over-the-counter) trading. Here, two parties trade directly with each other and do not use an official stock exchange. This allows the contracting parties to agree on prices individually.

OTC trading is more flexible than exchange trading. At the same time, it offers less security and has long been less regulated. Regulatory frameworks are now in place to create greater transparency and market integrity in this area. One example of this is the REMIT II Regulation. It ensures clear rules, for example through transparency and reporting requirements.

The energy transition has significantly changed intraday trading. The share of renewable energies such as solar and wind is growing. As a result, electricity production is fluctuating more strongly.

This is why the intraday electricity market is becoming increasingly important. Traders can react quickly here when the weather or consumption changes. This keeps the balancing group (a virtual energy account consisting of feed-in and feed-out) balanced. In this way, the intraday market ensures grid stability and security of supply.
 

Battery storage systems are playing an increasingly important role in intraday trading. They store energy when too much is produced. When energy is needed, they release it again. This helps to stabilize intraday electricity prices.

The Europe-wide intraday market was initially developed in the XBID project and then transferred to SIDC.

What is XBID?
XBID stands for Cross-Border Intraday Market Project. It was a project run by European electricity exchanges and transmission system operators. The aim was to develop cross-border intraday trading.

Technically, XBID was a joint platform with a Standard Order Book (SOB), a Capacity Management Module (CMM), and a Shipping Module (SM). This allowed bids from different countries to be consolidated, matched, and executed—depending on the available cross-border transmission capacities.

The merging of countries via cross-border capacities is called market coupling. This has been developed since 2006 to create a European single market for electricity.

What is SIDC?
The current SIDC (Single Intraday Coupling) is a direct continuation of the XBID project.

SIDC uses the same technical infrastructure as XBID—i.e., shared order books, shared capacity management, and shipping.

What does SIDC mean for market participants?
When people talk about cross-border intraday trading today, they are referring to SIDC. Participants such as traders and energy companies can use SIDC to trade electricity across Europe—not just nationally. This provides greater liquidity and better opportunities to offset short-term fluctuations.

Various players operate in the market:

• Intraday traders: They focus on short-term trading and rely on rapid price movements. 
• Utilities and grid operators: They use the market to balance their energy balance.
• Financial investors: They often have a speculative interest and rely on price changes in the market.

Speed is of the essence in intraday trading. Electricity prices can change in a matter of seconds. Successful traders constantly monitor the energy market and react at lightning speed. The following strategies and tools are useful in this regard:

Algo trading
In algo trading, programs trade automatically according to specific rules. They evaluate data such as weather, grid load, electricity production from renewable energies, or current demand. When the electricity price reaches a certain threshold, the system buys or sells fully automatically. This allows traders to take advantage of opportunities that humans often cannot recognize so quickly.

Swing Trading
Swing trading refers to when traders take advantage of short- to medium-term price fluctuations. Similar to stocks or commodities, traders attempt to profit from price movements.

Intraday trading thrives on speed, data, and automation. Professional market participants rely on specialized software solutions that combine trading platforms, forecasting tools, reporting, and battery storage integration. These tools enable automated decisions and precise market observation.

Market analyses and forecasts
Traders monitor the feed-in of renewable energies, planned power plant revisions or unplanned power plant outages, and changes in consumption behavior. Data analysis and forecasting tools show weather forecasts, grid load data, and electricity production from solar and wind energy. Information on balancing groups also helps to identify deviations early on and compensate for them quickly.

Trading platforms
The most important platforms for intraday trading are EPEX SPOT and the XBID or SIDC system. Traders can use these platforms to buy and sell electricity in continuous intraday trading – often within seconds. Modern user interfaces display the current intraday electricity price, available quarter-hourly contracts, and trading volumes in real time. In addition to the exchange, many market participants also use brokers for OTC (over-the-counter) trading. These enable direct transactions between companies, for example via specialized online platforms.

Algo trading software
It evaluates market prices, forecasts, and network data in milliseconds and decides when to buy or sell electricity. This is particularly important in the intraday market, where prices can change every second.

Risk management and reporting
Professional systems offer modules for risk management and reporting. They monitor open positions, evaluate market movements, and automatically calculate profits and losses.

Integration of battery storage systems
Some software solutions integrate battery storage systems directly. This allows traders to automatically decide whether stored electricity should be sold or stored, depending on the current intraday electricity price. In conjunction with algo trading, this creates a virtually self-regulating system for short-term wholesale electricity trading.

• High flexibility thanks to quarter-hourly contracts
• Ability to balance fluctuations in solar and wind energy
• Efficient integration of renewable energies
• Exploitation of short-term price fluctuations
• Stabilization of balancing groups and grids
• Efficient use of algo trading and battery storage

Despite the advantages, there are risks that require good management:

• Price risks: The intraday electricity price can change very quickly.
• Technical risks: Software errors or data problems can disrupt trading.
• Complexity: Different markets, many market participants, fluctuating feed-in, and complex data situations make for a high degree of complexity.

Intraday trading is a key component of the modern electricity industry. The EPEX SPOT exchange, with its SIDC intraday trading, and OTC trading ensure a transparent and dynamic market. Digital tools, algorithmic trading, and battery storage are driving this development forward. Those who understand the market make a significant contribution to the integration of renewable energies and the stabilization of electricity grids.

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