Optimization of energy systems sizing and operation including heat integration and storage

Abstract

Sustainable energy solutions are highly dependent on the availability and costs of resources during their operation. For instance, power output of solar cells and wind turbines vary over time which impacts the technical, economic, and environmental feasibility of Power-to-X (P2X) systems. In addition, efficient system solutions for energy conversion will require an optimal heat integration between several technologies and conversion routes. Thus, several methods have been proposed to conceptualize and optimize the design and operation of process plants. However, the possibilities of heat integration and storage during dynamic operation of different P2X-processes have been rarely evaluated by existing methods in literature. In this context, this research aims to provide an optimization framework, based on linear optimization and pinch analysis, to fill this knowledge gap, crucial to the development of dynamic renewable systems. The novel method is exemplified in the optimization of a Power-to-Methanol plant using solid oxide cells (SOCs) subjected to varying electricity production of wind turbines. The optimization estimates a minimal methanol production cost of 1772-1793 USD/ton for integrated scenarios and 1820-1807 USD/ton for non-integrated cases. Thus, heat integration plays a crucial role in cutting up to 2% of fuel production cost, while storage and optimal operation reduces further 3.3 % of the electrolysis size compared with reference scenarios.