Techno-economic implications of time-flexible operation for iron-based chemical looping combustion cycle with energy storage capability

Abstract

The renewable energy is predicted to be further expanded to reduce the fossil energy and associated CO2 emissions with the aim of achieving climate neutrality. One of the main issues in large-scale deployment of wind and solar power applications is the time-variability of these renewable sources. To tackle this issue, the modern energy conversion systems must have an inherent time-flexibility. The chemical looping combustion (CLC) is an innovative energy-efficient system with inherent CO2 capture. This work evaluates a time-flexible natural gas-based CLC system for efficient power generation (250 MW net electricity production) and very high decarbonization rate (>99%). The iron-based CLC cycle is fitted with Oxygen Carrier (OC) storage facilities (for both oxidized and reduced stages) to enhance the thermo-chemical energy storage capability. Two illustrative process layouts were assessed: one conventional base-load system and one with energy storage capability for flexible time operation. Various relevant process engineering tools were employed: process modelling and simulation, validation, energy integration, techno-economic assessment. The integrated evaluation of main techno-economic indicators shows that the time-flexible design has improved performance indicators such as lower specific investment costs (down to about 3%), reduced operational and power generation costs (down to about 2%) as well as lower CO2 capture costs (down to 8%).