Optimal sizing and operation of hydrogen generation sites accounting for waste heat recovery

Achieving cost-effective hydrogen production is key to facilitating the use of hydrogen as an alternative to fossil fuels. This study adopts a mixed integer linear programming approach to simultaneously derive the optimal sizing and operation of hydrogen generation sites. Waste heat recovery solutions to serve a district heating network were considered, resulting in an 18.9% reduction in hydrogen production costs compared to conventional designs, with up to 5.3% of the reduction attributable to waste heat utilization. A global sensitivity analysis indicated that renewable availability, imported electricity costs, and electrolyzer conversion efficiency are the most influential parameters in reducing total costs. Additionally, the study explores the impact of modeling fidelity on optimization results, revealing that nominal efficiency assumptions commonly used in the literature can lead to sizing errors and cost inefficiencies. Implementing piecewise linear approximations for electrolyzer performance significantly enhances the accuracy of these predictions. Overall, the findings underscore the crucial interconnection between the optimal sizing and operation of hydrogen generation sites, emphasizing that these should not be treated as separate steps in the design process. This work provides a robust foundation for advancing the optimal design of hydrogen generation sites and offers practical recommendations to reduce hydrogen costs.