REA: Resource Exergy Analysis – A Key to Climate Sustainability

Abstract

Resource exergy analysis (REA) is a method to comprehensively assess the resource consumption of technical systems. It is based on the physical property “exergy”, which goes beyond conventional energy analysis by considering energy quality. Combining exergy with a scientific definition of natural resources, REA can provide a comprehensive quantification of the resource consumption caused by any demand. REA introduces resource exergy consumption as a new key metric for the assessment of technical systems. In combination with an assessment of the direct greenhouse gas emissions, it allows quantifying climate sustainability consistently. The use of REA can be a key to climate sustainability by helping to minimize wastefulness and, consequently, indirect greenhouse gas emissions.

In this paper, a sample comparison using REA and a complementary greenhouse gas analysis is provided that illustrates why REA is a key to assessing the climate impact of technologies more comprehensively than with many alternative methods. Specifically, the following systems are compared: heat supply using an individual natural gas boiler, an individual boiler using green hydrogen from wind power and district heating generated with a large heat pump using wind power. To illustrate the differences, exergy passes are used. They are a visualization tool to make REA results more transparent.

The sample analysis illustrates how REA helps to avoid greenwashing and thus support climate sustainability by complementing direct greenhouse gas emissions analysis.