Francesco Pomponi

Embodied carbon mitigation and reduction in the built environment – What does the evidence say?

Of all industrial sectors, the built environment puts the most pressure on the natural environment, and in spite of significant efforts the International Energy Agency suggests that buildings-related emissions are on track to double by 2050. Whilst operational energy efficiency continues to receive significant attention by researchers, a less well-researched area is the assessment of embodied carbon in the built environment in order to understand where the greatest opportunities for its mitigation and reduction lie. This article approaches the body of academic knowledge on strategies to tackle embodied carbon (EC) and uses a systematic review of the available evidence to answer the following research question: how should we mitigate and reduce EC in the built environment? 102 journal articles have been reviewed systematically in the fields of embodied carbon mitigation and reduction, and life cycle assessment. In total, 17 mitigation strategies have been identified from within the existing literature which have been discussed through a meta-analysis on available data. Results reveal that no single mitigation strategy alone seems able to tackle the problem; rather, a pluralistic approach is necessary. The use of materials with lower EC, better design, an increased reuse of EC-intensive materials, and stronger policy drivers all emerged as key elements for a quicker transition to a low carbon built environment. The meta-analysis on 77 LCAs also shows an extremely incomplete and short-sighted approach to life cycle studies. Most studies only assess the manufacturing stages, often completely overlooking impacts occurring during the occupancy stage and at the end of life of the building. The LCA research community have the responsibility to address such shortcomings and work towards more complete and meaningful assessments.

Trust development and horizontal collaboration in logistics: a theory based evolutionary framework

Purpose – The purpose of this article is to provide academicians and practitioners alike with a theory-based framework regarding horizontal collaboration in logistics. The proposed tool is based on an incremental perspective, according to two main dimensions: mutual trust among partners and the extent of the cooperation. Design/methodology/approach – This study used a “synthesising” approach to gauge potential contributions previously spread across different streams of research and disciplines that are now integrated into the framework. We conduct a deep literature review to characterise the horizontal collaboration phenomenon along two levels of analysis. In doing so, we examined relevant literature in the field of horizontal cooperation in logistics to critically appraise aims of, impediments to and existing models for horizontal collaboration. Additionally, we reviewed seminal literature of four organisational theories to assess their potential to contribute to the theoretical foundations of the growin...

An Investigation into GHG and non-GHG Impacts of Double Skin Façades in Office Refurbishments

The building sector is a major contributor to energy consumption, greenhouse gas (GHG) emissions, and depletion of natural resources. In developed countries, existing buildings represent the majority of the stock, their low‐carbon refurbishment hence being one of the most sensible ways to mitigate GHG emissions and reduce environmental impacts of the construction sector. This article has investigated and established the GHG and non‐GHG life cycle impacts of several double skin facade (DSF) configurations for office refurbishments by means of a parametric comparative life cycle assessment against up‐to‐standard single skin facade (SSF) refurbishment solutions. Two different methods were used to assess both GHG emissions and other environmental impacts. Results show that if, on the one hand, most of the DSF configurations assessed actually reduce GHG emissions compared to SSFs over their life cycle — thus supporting a wider adoption of DSFs for low‐carbon refurbishments — on the other hand, there exist non‐negligible ecological and environmental impacts that the DSF generates, specifically in terms of some materials of the structure and their final disposal. Research attention is thus needed regarding the environmental impacts of the materials used for DSFs and not only in minimizing the energy consumption of the operational phase.

Life cycle assessment of domestic hot water systems: a comparative analysis

On average, hot water is responsible for 18% of residential energy consumption and corresponding greenhouse gas (GHG) emissions. Several domestic hot water systems (DHWSs) are commonly used but their life cycle impacts are yet to be established comprehensively. This is due to those impacts varying significantly within the context and the system boundaries of the assessment. This article reports findings from a comparative cradle-to-grave life cycle assessment (LCA) of five DHWSs in the UK context. Primary data acquired from a case study contributed to achieving accurate life cycle inventories that were then modelled in SimaPro through the ecoinvent database. Global Warming Potential (GWP) is the impact assessment method used. Amongst the five types, solar heater with electric backup appears to be the least damaging alternative. The study also reinforces the importance of adopting a cradle-to-grave approach if LCA results are to accurately reflect environmental impacts holistically and lead to better, more informed decisions.

Double skin façade (DSF) technologies for UK office refurbishments: A systemic matchmaking practice

Purpose – The purpose of this paper is to establish how UK offices and double skin facade (DSF) technologies can be best matched for refurbishment purposes. Design/methodology/approach – This research uses a mixed methodology including primary and secondary data collection, analysis and interpolation through document analysis, comprehensive critical literature review, and case study approach. Findings – In total, 22 benchmarks have been developed to represent 75 per cent of the existing office stock in the UK. Through a comparison with 36 case studies of European buildings refurbished with DSFs, two benchmarks showed to be most suitable for a DSF refurbishment and most appropriate configurations for a successful DSF refurbishment have been identified. Findings have been also checked against a large sample of DSF buildings in the UK. Research limitations/implications – The benchmarks delivered in this study can be developed further into parametric models, where variations can be obtained by changing the pa...

Embodied and Life Cycle Carbon Assessment of Buildings in Latin America: State-of-the-Art and Future Directions

This chapter provides a comprehensive overview of the state of the art on embodied carbon and life cycle assessment (LCA) of buildings in the context of Latin America. It reviews the current situation by assessing existing policies and initiatives aimed at, or related to, the themes of embodied carbon and life cycle environmental impacts caused by buildings. Additionally, it investigates the availability of geographically relevant data, which forms the basis of reliable and realistic assessments. An in-depth review of available sources reveals a severe scarcity of building-related data in Latin America. To this end, we suggest three methods to sensibly adapt available world data to Latin America as a temporary measure to utilise until more robust datasets are developed by governments and other stakeholders. Each of the methods relates to one of the three main approaches currently used in LCAs, namely, process-based, input-output and hybrid – thus allowing more accurate assessments across the whole spectrum of LCA methodologies. The chapter concludes with suggestions for future efforts and with a plea to all stakeholders to work together for a quicker transition to sustainable built environments in Latin America.

Uncertainty analysis in embodied carbon assessments : What are the implications of its omission?

Embodied carbon assessments of buildings are not methodologically very different from the more well-known life cycle assessments (LCAs). In particular, the two also share the frequent lack of uncertainty analysis in many assessments produced by academics as well as practitioners. An assessment that omits uncertainty analysis generally results in a single, very definite numerical output which however embeds no information on the likelihood of that value being true. Similarly, in comparative studies, the assessment produces two values, and the main outcome is merely reduced to a higher/lower comparison in order to choose the alternative allegedly less detrimental to the environment.

A Method for Visualising Embodied and Whole Life Carbon of Buildings

Embodied and whole life carbon of buildings are increasingly gaining attention. However, embodied carbon calculation is still far from being common practice for sustainability assessment of buildings. Some of its greatest difficulties lie with the long life span of buildings which implies a great unpredictability of future scenarios and high uncertainty of data. To help understand which life cycle stages should get the most attention when considering a building project, this chapter proposes a new visualisation method based on Sankey diagrams for whole life carbon that allows one to cluster the carbon emitted in each of the life cycle stages as identified in current BS 15978 standards. With the proposed method, the carbon figures can be further broken down to account for building assemblies and components. Additionally, the method is equally suitable to account for physical quantities of what is embedded in buildings and their components. As such it can supplement some units of existing assessment methods (e.g., metal depletion measured in mass units of Feeq) and turn it into mass units of embodied steel. With such new metric, a life cycle assessment would include knowledge on flows as well as quantities. Such information could then be linked to the building permanently and smartly to be updated when necessary as the building evolves, changes, and gets upgraded, building on the theoretical foundations of the shearing layers of buildings. As such, this information could be embedded within BIM which is fully suitable to store parametric details for each building component.

A Theoretical Framework for Circular Economy Research in the Built Environment

Circular economy is quickly gaining momentum across numerous research fields. The founding principles of circular economies lie in a different perspective on, and management of, resources under the idea that an ever-growing economic development and profitability can happen without an ever-growing pressure on the environment. As such, the built environment has a lot to contribute, being the sector with the greatest environmental impacts. However, the few existing cases of current research in the built environment from a circular economy perspective seem to have just replaced the 3R principle (reduce, reuse, recycle) with the new ‘buzz-word’. In this paper, we argue that a significantly different research approach is necessary if the circular economy is to keep up to its promise of being a new paradigm for sustainability. We therefore propose a framework to formulate building research from within a circular economy perspective. The framework is built around six pillars and acknowledges the key role of interdisciplinary research and that of both bottom-up and top-down initiatives to facilitate the transition to ‘circular’ buildings. Although theoretical in nature, the framework has been tested against current discourse about buildings and circular economies and it has proven a valuable tool to cluster existing initiatives and highlight missing interdisciplinary links. As such it can provide a valuable starting point to contribute to the theoretical foundations of building research from within the new paradigm of circular economies and also shape future research directions.

Reducing Embodied Carbon in the Built Environment: A Research Agenda

In spite of significant global efforts, the International Energy Agency suggests that buildings-related emissions are on track to double by 2050. Whilst operational energy efficiency continues to receive significant attention by researchers, a less well-researched area is the assessment of embodied carbon in the built environment in order to understand where the greatest opportunities for its mitigation and reduction lie. This paper reports on available mitigation strategies to tackle embodied carbon identified through a systematic review of the available academic evidence. It also investigates the scope and scale of current academic investigations to highlight where significant gaps are for impactful further research on the topic. In total, 17 mitigation strategies have been identified from within the existing literature which have been discussed individually. Results reveal that a one-size-fits-all approach is unlikely to yield beneficial results and future research should be diverse in breadth and scope, locally accurate, and significantly interdisciplinary.