Harvesting big data from residential building energy performance certificates: retrofitting and climate change mitigation insights at a regional scale

João Pedro Gouveia,Pedro Palma

doi:10.1088/1748-9326/ab3781

Abstract

The reduction of energy consumption and the increase in energy efficiency is currently an important cornerstone of EU policy. Energy performance certificates (EPCs) were implemented as one of the tools to promote this agenda, and are used for the energy performance assessment of buildings. In this study, the characteristics of the Portuguese dwelling stock are regionally analysed using data from approximately 523,000 Portuguese residential EPCs. Furthermore, a bottom-up building typology approach is used to assess the regional energy needs impact of retrofitting actions and to estimate the heating and cooling energy performance gaps of the whole dwelling stock, as well as the potential CO2 emissions resulting from the gaps’ potential offset due to increase thermal comfort. The results show that Portuguese residential buildings have very low energy performance, with windows and roofs being identified as the most energy inefficient elements. Roof retrofitting has the highest potential for the reduction of energy needs. The estimated heating and cooling energy performance gap amount to very significant percentages, due to the poor performing building stock but also very low energy consumption levels, with probable consequences for the thermal comfort of occupants. Assuming the current energy mix, carbon emissions would be 9.8 and 20.2 times higher associated with heating and cooling, respectively, if the actual final energy consumption were to match the estimated theoretical values derived from building regulation. This study demonstrates several application cases and leverages the potential of the individual EPC, increasing the detail in the dwelling stock characterization and energy performance estimation, revealing its value for energy retrofit and climate change mitigation assessments, as well as establishing the ground for future work related to building retrofits, energy efficiency measure implementation, climate change mitigation, thermal comfort, and energy poverty studies.

Highlights

Energy consumption is at the core of economic development, but its severe impacts on the depletion of resources and climate change have justified a call for general reduction across all economic activities
Regional building typology characterization Of the sample of approximately 523, 000 residential Energy performance certificates (EPCs), which are mandatory for new houses and houses in the market, about 87.8% have a ‘C’ rate or less, which is an indicator of the poor energy performance and energy inefficiency of the dwelling stock
Residential sector consumption is a moving target, which increases the complexity of adequate policies and instruments for addressing in some countries the bottleneck between increased demand for, e.g., climatization due to the current lack of thermal comfort; and complying with the objectives of increased energy efficiency which intend to reduce energy consumption (Gouveia 2017)

Summary

Introduction

Energy consumption is at the core of economic development, but its severe impacts on the depletion of resources and climate change have justified a call for general reduction across all economic activities. The residential sector is crucial to achieving carbon dioxide (CO2) emission reductions, as it has an important energy-saving potential, and its environmental controls are difficult to displace to other countries (Pablo-Romero et al 2017). Energy consumption in residential buildings represents a significant share of energy consumption in OECD countries; it varies significantly among the EU28 (e.g. from 12% in Luxembourg, to 37% in Croatia) (PORDATA 2016). When looking to the importance of space heating in residential buildings, total final energy consumption varied across member states from 22% (in Portugal) to 83% (in Denmark) in 2016 (Odyssee-Mure 2019). Space cooling is becoming an increasingly relevant issue in Europe, albeit still representing a residual percentage of consumption (Odyssee-Mure 2019). Data on space cooling final energy demand in residential buildings of the EU member states is still limited (Jakubcionis and Carlsson 2017)

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