Empirical and dynamic primary energy factors

Current legislation, standards, and scientific research in the field of energy efficiency often make use of PEFs (primary energy factors). The measures employed are usually fixed and based on theoretical calculations. However given the intrinsically variable nature of energy systems, these PEFs should rely on empirical data and evolve in time. Otherwise the obtained efficiencies may not be representative of the actual energy system. In addition, incorrect PEFs may cause a negative effect on the energy efficiency measures. For instance, imposing a high value on the PEF of electricity may discourage the use of renewable energy sources, which have an actual value close to 1. In order to provide a solution to this issue, we propose an application of the Energy Networks (ENS), described in a previous work, to calculate dynamic PEFs based on empirical data. An EN represents an entire energy system both numerically and graphically, from its primary energy sources to their final energy forms, and consuming sectors. Using ENs we can calculate the PEF of any energy form and depict it in a simple and meaningful graph that shows the details of the contribution of each primary energy and the efficiency of the associated process. The analysis of these PEFs leads to significant conclusions regarding the energy models adopted among countries, their evolution in time, the selection of viable ways to improve efficiency, and the detection of best practices that could contribute to the overall energy efficiency targets. (C) 2014 Elsevier Ltd. All rights reserved.