Effect of Embodied Energy on Cost-Effectiveness of a Prefabricated Modular Solution on Renovation Scenarios in Social Housing in Porto, Portugal

Manuela Almeida,Ricardo Barbosa,Raphaele Malheiro

doi:10.3390/su12041631

Abstract

A large-scale energy renovation intervention in existing buildings has been consistently presented as the most significant opportunity to contribute to achieving the European targets for 2030 and 2050. One of the key points for such achievement is the cost-effectiveness of the interventions proposed, which is also closely related to decent housing affordability. Prefabricated modular solutions have been pointed out as a pathway, but there are knowledge gaps regarding both its cost-effectiveness and its environmental performance. Considering a social housing multi-family building in Porto, Portugal, as a case study, this research employs energy simulations, a cost-optimal methodology and a life cycle analysis approach to assess the influence of considering embodied energy and emissions in cost-effectiveness calculations. In general terms, the hierarchical relation between calculated renovation scenarios remain identical, as well as the choice of the cost-optimal combination, which can reduce primary energy needs by 226 kWh/(y.m2). However, embodied carbon emissions and embodied energy of the materials used in the calculations, which are indicative of the sustainability of such interventions, increase the energy and carbon emissions associated to each renovation package by an average of 43 kWh/(y.m2) and 9.3 kgCO2eq/(y.m2), respectively.

Highlights

Cities hold significant responsibility in terms of energy and resources consumption
Regarding the building sector and within the regulatory initiatives elaborated in this context, the Energy Performance of Buildings Directive (EPBD), and in particular, its recast in 2010, can be considered a turning point where new game-changing concepts were introduced, such as the nearly Zero-Energy Buildings [6], which are characterized by a high energy performance
This paper investigates the influence of the embodied energy and embodied carbon emissions on the cost-effectiveness of several renovation scenarios in a southern European context, compiling different solutions, including a modular prefabricated panel developed in the University of Minho in a framework of a European research project designated as MORE-CONNECT

Summary

Introduction

Cities hold significant responsibility in terms of energy and resources consumption. Urban areas, which accommodate more than half of the global population, consume up to 80% of global material and energy supplies and produce around 75% of the carbon emissions worldwide [1]. The nearly zero or very low amount of energy required in these buildings must be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby [6]. According to this directive, Member States should ensure that from 31 December 2020, all new buildings are built as nZEB [6]. Considering the significant energy reductions that can be achieved by cost-effective energy renovations and that the replacement rate of existing buildings by new buildings is only around 1% to 2% per year [8], there is significant potential for decarbonization of the building stock

Methods

Results

Conclusion