Evaluation of Primary Energy from Photovoltaics for a Nearly Zero Energy Building (nZEB): A Case Study in Lithuania

Rokas Tamašauskas,Jolanta Šadauskienė,Violeta Medelienė,Dorota Anna Krawczyk

doi:10.3390/proceedings2020051005

Abstract

The European Commission has set the target in the Energy Efficiency Directive (EED) to reduce EU primary energy consumption in 2020 by 20%. A crucial aspect of the overall assessment of energy saving measures that affect electricity demand is the primary energy factor that is used for evaluation of primary energy consumption from renewable energy resources in a Nearly Zero Energy Building (nZEB). The analysis of the resources has revealed that energy from photovoltaics is evaluated using different methods. Therefore, this article’s aim is to investigate and evaluate the primary energy factor of energy from photovoltaics using the data of produced and consumed energy of 30 photovoltaic (PV) systems operating in Lithuania. Investigation results show that the difference of non-renewable primary energy factor between the PV systems due to capacities is 35%. In addition, the results of the studies show that the average value of the primary energy factor of PV systems in Lithuania is 1.038.

Highlights

Reducing energy consumption of existing buildings and achieving nearly zero energy buildings (NZEBs) are the main focuses of the Energy Efficiency Directive (EED) [1] and of the EnergyPerformance of Building Directive (EPBD) [2]
This study provides guidelines for the primary energy factor determination; each case should be carefully examined on an individual nearly zero energy building (NZEB) basis and the local climate, especially when there is no exact methodology for determining
The investigation has shown that the primary energy factor may depend on the capacity of the PV systems

Summary

Introduction

Reducing energy consumption of existing buildings and achieving nearly zero energy buildings (NZEBs) are the main focuses of the Energy Efficiency Directive (EED) [1] and of the EnergyPerformance of Building Directive (EPBD) [2]. Directive (EU) 2018/844 [3] recommends to use renewable energy sources that consist of more than a half of the total energy, and to reduce the amount of non-renewable energy used in energy-efficient buildings. The part of energy from a non-renewable energy source cannot be defined because it depends on the additional energy consumed in the conversion device, which normally uses non-renewable energy, such as electrical energy, a common grid or fuel [4]. A primary energy factor, often referred to as a conversion factor, is required to calculate the total energy consumption, including the chain of energy generation based on the final energy consumption data. The primary energy factor is a sum of renewable energy factor fP,ren and nonrenewable factor fPn,ren.

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