Modeling and Optimization Operation of Improved Power-to-Hydrogen-and-Heat Method at Low Temperature for Reducing Carbon Emissions

The power-to-hydrogen-and-heat (P2HH) method is a potential means of improving energy efficiency while reducing carbon emissions. However, existing P2HH methods are ineffective at low temperatures, and do not consider physical constraints on heat exchange between the electrolyzer and heating network. Hence, this paper proposes an improved P2HH (IP2HH) method to overcome these shortcomings. First, this paper proposes a novel collaborative mechanism between the electrolyzer and the heating network. In this system, the electrolyzer can not only transfer excess heat to the heating network when at high temperatures, but can also be heated by the heating network when at low temperatures. Second, this paper takes the physical limitations of heat exchange between electrolyzer and heating network into consideration, and models the regulating valve of heat exchanger. These considerations allow produce simulation results that better approximate real-world scenarios. Finally, a convex model integrated with the IP2HH approach is established. Compared with the existing P2HH method, the IP2HH method may allow electrolyzer to work intermittently based on fluctuations in renewables supplies while maintaining high hydrogen production efficiency. Such improvements could reduce carbon emissions by 35.5%, costs by 10.7%, and renewables curtailment by 26.4% at ambient temperature of 1 $^{\circ }$ C.