Where to market flexibility? Integrating continuous intraday trading into multi-market participation of industrial multi-energy systems

The rising share of volatile renewable electricity generation increases the demand for flexibility. Flexibility can be offered by industrial multi-energy systems and marketed either on the continuous intraday, day-ahead, or balancing-power markets. Thus, industrial multi-energy systems face the question where to market their flexibility. We propose a two-step method to integrate trading on the continuous intraday market into a multi-market optimization for flexible industrial multi-energy systems. First, we estimate revenues from continuous trading in the intraday market, employing option-price theory. Second, a multi-stage stochastic optimization allocates the flexibility to the three markets. The case study of an industrial multi-energy system demonstrates that coordinated bidding in all three markets reduces costs the most. A sensitivity analysis reveals that the optimal split between the different markets strongly depends on the intraday market volatility. Overall, the proposed method provides a practical decision-support tool for multi-energy systems participating in short-term electricity and balancing-power markets.