The levelized cost of exergy: a technoeconomic framework for energy system comparison

Abstract

While the levelized costs of electricity and heat have been quantified before, these two metrics cannot be directly compared, due to the different exergy content of heat and work. To address this, we develop a levelized cost of exergy (LCOEx) framework that enables direct comparisons between energy sources and processes. We find that moderate-and high-grade heat have an LCOEx that is comparable to electricity (5 -10 ¢/kWhex), while low-grade heat sources have much higher LCOEx values (> 50 ¢/kWhex). The LCOEx of a system's output is affected by (i) the LCOEx of the system input, (ii) the CAPEX of the system, and (iii) the exergetic efficiency of the system. We use our framework to identify which processes are already achieved with relatively high cost effectiveness (production of fuels, hydrogen, and ammonia) and which have room for improvement (dehumidification, food production).