The necessity to standardise primary energy quality in achieving a meaningful quantification of related indicators

Abstract

The representativeness of several important parameters, such as energy return on investment (EROI) and those requiring summing primary energy (PE), are often questioned due to the gap in PE quantification technique. This fundamental gap is systematically investigated in order to clarify the PE quantification problem, its impact, and propose a justifiable solution using a widely used tool, such as EROI, together with appropriate data and scenarios. The analysis shows that present PE estimation lacks scientifically justifiable grounds to compare any parameters that depend on it. For example, present EROI calculation is unsuitable for technology-to-technology or system-to-system or system-to-technology comparisons because of the variation of primary energy quality (PEQ) with a resource-technology combination. The main cause of PEQ discrepancy is the absence of reference energy quality that facilitates proper comparison and interconversion. This study shows that standardising PEQ enables a scientifically meaningful quantification of PE and a justifiable comparison of EROI as well as other relevant indicators depending on it. Electricity emerges as the best option for solving the differences in PEQ in the short-term. However, the logical long-term solution is to standardise the energy unit “joule” to attain a definite value, similar to kilogram, across the various sub-areas of energy.