Germany’s intraday market is deep and liquid, but the opportunity from extreme price spikes is limited. Part I of this article showed why German intraday saturation will happen: as BESS capacity grows faster than renewables, batteries compete with each other rather than shadow-bidding gas plants, and intraday continuous prices show fewer price spikes.

But knowing that saturation will come is not the same as knowing when, or by how much. That is the key question for developers and investors modelling intraday revenues through the 2030s and beyond.

Modo Energy models intraday saturation at 15-minute resolution. For every quarter-hour across the forecast horizon, the model computes how much BESS is available to deal with forecast errors. As BESS is added to the system, intraday prices begin to close in on their fundamentals-based fair value.

​For more information about the topic or any questions on methodology, contact till@modoenergy.com.

Key takeaways

• Modo Energy applies intraday saturation to modelled prices rather than to battery capture. The model compresses the standard deviation of the traded vs. intraday auction price spread from roughly 15 EUR/MWh in 2026 to around 8 EUR/MWh by the mid-2030s.
• Saturation does not mean volatility disappears or that forecast error gets eliminated. Higher BESS liquidity helps price formation, so that traded intraday continuous prices better match their ideal fundamentals-based “fair value”.
• Modo Energy computes saturation on a 15-minute basis, checking how much uncommitted battery capacity is available to deal with the forecast error. This reduces overall volatility but keeps price spikes in place where they stem from a fundamental driver.

Intraday saturation means better alignment of traded intraday prices with a fundamental view

Part I showed that BESS reduces intraday price spikes. More batteries mean greater liquidity near delivery, and gas peakers lose their ability to name scarcity prices. That part of the volatility disappears.

But intraday saturation does not mean pure convergence on the day-ahead price: forecast error is a physical feature of the market, not a liquidity problem. When renewable output misses its day-ahead forecast, someone must trade the gap before delivery. That transaction drives a price move. BESS absorbs it more smoothly than a thin order book does, but it does not remove the signal: intraday prices won’t perfectly match day-ahead prices, even with more BESS.

Instead, better liquidity helps price formation in the intraday view, meaning prices align better with market fundamentals. With more BESS, intraday prices should match up more closely with what the “fair value” of a fundamentals-based intraday price should be, not perfectly match up with the day-ahead. In our modelling, the difference between a traded and a fair-value (”auction”) price drops over time as the BESS-RES ratio grows.

There are two distinct components of intraday volatility: the trading element seen in price squeezes and jumps, which BESS compresses, and the residual forecast-error correction, which persists.

Three price series separate noise from fundamentals

To explain this better, it is worth drilling into the modelling methodology applied here. Modo Energy models three distinct price series for Germany: day-ahead (DA), intraday auction (IDA), and intraday continuous (IDC).

The DA price reflects a fundamentals view that contains some forecast inaccuracy, as any day-ahead auction must. The IDA price is solved without that forecast error, on a clean fundamentals view. This shows the clear difference in how much the price should move based solely on forecast errors.