Utilization of excess heat in future Power-to-X energy hubs through sector-coupling

This study focuses on harnessing excess heat from Power-to-X technologies in future energy hubs. By coupling thermodynamics with an optimization model, a novel analysis is performed using the Greenlab Skive energy hub, which includes hydrogen and methanol synthesizers, as a case study. Pinch analysis techniques are employed to design a heat exchanger network that can thermally integrate processes within the energy hub. Through the EnerHub2X modelling framework, three scenarios are optimized to explore and compare the potential of excess heat recovery. Excess heat is utilized through an optimally designed heat exchanger network, which achieves up to 3.49 MW of heat recovery. This leads to increased profits due to reduced natural gas costs and higher methanol sales. Upgrading excess heat and distributing it to the district heating network yields the highest profit, driven by increased compressed hydrogen and methanol production and the sale of heat to district heating. Thermal integration reduces waste heat by 14.5%, while utilizing excess heat in the district heating network results in 60% further reduction. An economic assessment confirms the feasibility and profitability of the project. Sensitivity analyses are undertaken to analyse the impact of critical parameters on the model, such as electricity and heat prices, along with the selling prices of methanol and hydrogen. The results highlight that excess heat utilization enhances profitability, energy efficiency, and sustainability. By implementing waste heat recovery techniques and exploring alternative options, future energy hubs can strengthen their business models and play a crucial role in Europe’s green transition and clean fuel production.