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Better Forecasts, Higher Trading Profits: BESS Revenue Capture in the German Day-Ahead Market
How much does price forecast accuracy affect BESS revenue? Electricity Maps and FlexUp ran an eight-month simulation in the German day-ahead market to find out. The Electricity Maps forecast outperformed a naive persistence baseline by €4,860 per MW and captured 90.7% of maximum achievable revenue. The study also shows why MAE, the metric most forecast evaluations are built around, is a poor predictor of revenue capture, and what to use instead.
Julien Lavalley
Battery storage operators trading the day-ahead auction face a problem most cannot quantify: how much is forecast quality actually worth, and how do you measure it?
This joint study by Electricity Maps and FlexUp provides a data-driven answer across three parts.
Part One simulates an eight-month BESS trading strategy in Germany using three forecasts:
1. persistence, 2. Electricity Maps, and 3. perfect foresight, and quantifies the revenue difference.
Part Two shows why MAE, the industry-standard evaluation metric, correlates poorly with captured revenue and introduces spread-weighted Spearman rank correlation as the metric that actually predicts dispatch performance.
Part Three maps revenue capture across 34 European bidding zones, showing that the same forecast skill translates into very different returns depending on where you trade.
The study covers the period from 1 October 2025 to 1 June 2026, using a 1 MW / 2 MWh BESS model with 85% round-trip efficiency and realistic bid rejection logic.
White paper
