Multi-market battery bidding outperforms single-market trading in Central Europe

If a battery can wait for the right price, it can turn market swings into cash. This paper looks at battery energy storage systems in the Central European wholesale power market, where they trade in the day-ahead auction and the continuous intraday market at EPEX Spot. The authors use a rolling intrinsic approach, a trading rule built for continuous intraday markets, and they include bid–ask spreads to reflect liquidity constraints. Their main result is straightforward: bidding across more than one market consistently beats staying in just one. They also show that maximum cycle limits matter a lot for profit. Batteries with more flexible cycling rules, especially ones that relax daily limits while still respecting annual limits, can capture more value. For the energy transition, that means the way a battery is allowed to trade can be as important as the battery itself.

In Central Europe, a battery can earn twice from the same hour. One chance comes in the day-ahead auction, where traders lock in tomorrow's plan. The other comes in intraday trading, where prices keep moving through the day. That second market is the twist. A battery can wait, then pounce when the bid-ask spread, the gap between buy and sell prices, looks right. The surprise here is simple. The best path is not one perfect market bet. It is moving across both markets, then giving the battery room to cycle. That room matters when renewables swing hard. It also matters when the battery must decide fast.

Two markets, one battery

The study compares market paths in the Central European wholesale power market. It looks at the day-ahead auction and the continuous intraday market at EPEX Spot. It uses rolling intrinsic, a trading rule that keeps reworking the plan as prices update. The key result is blunt. Multi-market bidding beats single-market participation again and again. That holds after the analysis counts bid-ask spreads, the gap between buy and sell prices. Those gaps matter because they eat into profit when few buyers and sellers are waiting. The other big result is about cycle limits. Tight daily limits can hold back earnings. More flexible rules, with annual limits kept in place, can open more value.

How rolling intrinsic keeps pace

Rolling intrinsic is built for a market that never stands still. The battery does not pick one fixed plan and hope. It updates the plan as new prices arrive. That makes it a realistic rule for continuous intraday trading, which never stops at one auction bell. The method also uses bid-ask spreads. That means it pays the real cost of trading, not a fantasy price. The battery then faces cycle limits, or caps on full charge-and-discharge loops. Daily caps limit how hard the battery can work today. Annual caps keep the total year within bounds. That matters because one extra turn can change the profit picture.

Why cycle limits matter

These results point to a simple message for battery owners. Trading rules can matter as much as hardware size. A battery that only plays one market leaves money on the table. A battery that can shift between day-ahead and intraday trading can use more price swings. The cycle finding matters too. Daily caps can shut down useful moves too early. A looser daily rule, paired with a yearly limit, gives the battery more chances to earn without ignoring wear and tear.

What this changes next

The core surprise is still the same. A battery's value does not live only in its cells. It also lives in the rules around trade timing. That means market design can unlock value without changing the hardware. A battery contract can relax daily cycling limits. It can still keep annual limits. That setup can capture more of the price swings in Central Europe. Flexibility becomes a market asset, not just an engineering one.