Optimal dispatch of wind-powered solid oxide electrolyzer plants

Solid oxide electrolyzer (SOEL) systems represent a promising hydrogen production technology for renewable energy plants, offering significant economic benefits due to their best-in-class efficiency. To fully harness their potential in dynamic scenarios, reliable dispatch strategies are essential. In this challenging context, this study develops a dispatch optimization framework for wind-electrolysis plants aimed at maximizing profitability. A key aspect of the framework is a detailed scheduling model of the SOEL system, which captures its nonlinear energy conversion behavior, three-state operation and ramp rate constraints. Notably, implementing a 1-week time horizon and a 5-minute resolution allows the model to account for both cold and warm startup durations of the SOEL. Simulations are conducted using 10 typical weeks of onshore wind generation and day-ahead electricity price data from Germany in 2019. Results indicate that the SOEL system exhibits a relatively stable operational pattern, predominantly following wind generation when in operation while occasionally switching to standby in response to extreme conditions, such as peak electricity prices or low wind power levels. Additionally, a comparative analysis between SOEL and proton exchange membrane electrolyzer (PEMEL) systems is conducted across technical, energy and economic metrics. The impact of varying hydrogen prices on dispatch outcomes is also investigated. Findings suggest that the PEMEL system exhibits greater dynamic behavior than the SOEL, with up to 13 times the total number of state transitions. However, despite its higher investment cost and shorter lifespan, the SOEL case shows a higher profitability, with an average net profit difference of 0.53 k€ and 2.01 k€ across all typical weeks under the hydrogen prices of 3 €/kg and 5 €/kg, respectively.