A tool for the parametric assessment of operational energy use and embodied GHG emissions in a single-family house concept study

An approach towards sustainable renovation—A tool for decision support in early project stages

In order to achieve the necessary reduction of greenhouse gas (GHG) emissions and decarbonization of building construction and operation, both high- and low-tech building design strategies are promoted. Amongst particularly promising strategies are the deployment of energy efficiency measures, for reducing operational energy use and related impacts, as well as the application of low-carbon, bio-based construction materials, for reducing embodied impacts.In part two of our study on the life cycle assessment (LCA) of regenerative design strategies, LCA is applied to investigate the environmental impacts and reduction potentials of strategies at building level by analyzing two low-tech, passive building concepts – the be2226 building and the N11 SolarHouse – in both their original designs as well as optimized alternatives applying bio-based material solutions.The analysis includes three steps. In a first step the life cycle GHG emissions of the original buildings are assessed, revealing strengths and weaknesses on both operational and embodied GHG emissions. Environmental hotspots are identified across environmental indicators, life cycle stages and building elements. In a second step the case studies are remodeled with bio-based building element alternatives showing substantial embodied GHG emissions reduction potential compared to the original case studies. Finally, the results of all building variants are compared with climate targets for buildings revealing that the N11 building meets established climate targets already in its original version, and that a straw-based material optimization can even enable meeting more ambitious climate targets.

A Parametric Tool for the Assessment of Operational Energy Use, Embodied Energy and Embodied Material Emissions in Building

The concept of (net) zero greenhouse gas (GHG) emission(s) buildings is gaining wide international attention and is considered to be the main pathway for achieving climate neutrality targets in the built environment. However, there is an increasing plethora of differing terms, definitions, and approaches emerging worldwide. To understand the current progress of the ongoing discussion, this study provides an overview of terms, definitions, and key features from a review of 35 building assessment approaches. The investigation identified that 13 voluntary frameworks from 11 countries are particularly characterised by net zero-carbon/GHG emissions performance targets, which are then subject to a more detailed analysis. The review was organised in the context of the project IEA EBC Annex 72 on “Assessing Life Cycle Related Environmental Impacts Caused by Buildings”, which involves researchers from over 25 countries worldwide.In the current dynamic political surroundings and ongoing scientific debate, only an initial overview of this topic can be presented. However, providing typologies and fostering transparency would be instrumental in delivering clarity, limiting misunderstanding, and avoiding potential greenwashing. To this end, this article categorises the most critical methodological options—i.e., system boundaries for both operational and embodied GHG emissions, the type of GHG emission factor for electricity use, the approach to the “time” aspect, and the possibilities of GHG emission compensation—into a comprehensive framework for clarifying or setting (net) zero GHG emission building definitions in a more systematic way.The article concludes that although variations in the existing approaches will continue to exist, certain minimum directions should be considered for the future development of harmonised (net) zero GHG emissions building frameworks. As a minimum, it is recommended to extend the usual scope of the operational energy use balance. At the same time, minimum requirements must also be set for embodied GHG emissions even if they are not considered in the carbon/GHG emissions balance.

Implementing China’s emission reduction regulations requires a design approach that integrates specific architectural and functional properties of railway stations with low greenhouse gas (GHG) emission. This article analyzes life cycle GHG emissions related to materials production, replacement and operational energy use to identify design drivers and reduction strategies implemented in high-speed railway station (HSRS) buildings. A typical middle-sized HSRS building in a cold climate zone in China is studied. A detailed methodology was proposed for the development and assessment of emission reduction strategies through life cycle assessment (LCA), combined with a building information model (BIM). The results reveal that operational emissions contribute the most to total GHG emissions, constituting approximately 81% while embodied material emissions constitute 19%, with 94 kgCO2eq/m2·a and 22 kgCO2eq/m2·a respectively. Optimizing space can reduce operational GHG emissions and service life extension of insulation materials contributes to a 15% reduction in embodied GHG emissions. In all three scenarios, the reduction potentials of space, envelope, and material type optimization were 28.2%, 13.1%, and 3.5% and that measures for reduced life cycle emissions should focus on space in the early stage of building design. This study addresses the research gap by investigating the life cycle GHG emissions from HSRS buildings and reduction strategies to help influence the design decisions of similar projects and large space public buildings which are critical for emission reduction on a larger scale.

Whole-building life-cycle analysis with a new GREET® tool: Embodied greenhouse gas emissions and payback period of a LEED-Certified library

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

The decarbonisation of the construction sector is critical to meet national and international climate goals. Literature gives many examples of measures for the reduction of greenhouse gas (GHG) emissions from buildings. However, few studies investigate the trade-offs between potentially conflicting GHG emission reduction measures or the affordability of these measures. Ydalir is a Zero Emission Neighbourhood (ZEN) pilot area in the Norwegian research centre for Zero Emission Neighbourhoods in smart cities. One of the major challenges Ydalir faces is how to reduce GHG emissions from the neighbourhood towards a net zero emission building (nZEB). Additional challenges include retaining social, environmental, and economical sustainability for both the project developer and building owners and avoid suboptimal solutions. This paper investigates the trade-offs between energy efficiency and material use for two scenarios. The scenarios are a Norwegian building code scenario and a passive house scenario. The analysis ascertains total energy demand, whole life cycle GHG emissions, and cost assessment for two housing units within Ydalir Torg. The results show lower total GHG emissions and lower GHG emissions from operational energy use in the passive house scenario, and an increase in GHG emissions from the production phase due to thicker levels of insulation. The cost assessment shows increased investment costs for the project developer in the passive house scenario, despite lower operational costs for the building owner. Total GHG emission payback times for the passive house scenario are at 18 - 19 years. Cost payback time varies between 10 - 37 years. This paper is useful for practitioners that wish to balance GHG emission reduction requirements between operational energy use, material use and affordability.

The agriculture and forestry sector accounts for approximately 24% of total greenhouse gas (GHG) emissions in Australia. Over the years researchers have produced new knowledge about agricultural GHG emissions and energy use patterns and opportunities to decrease them, albeit in small-scale studies or large-scale ones with coarse resolution. Linking the multiple, diverse and rich datasets around agricultural production in Australia into one dataset that allows for an estimate of GHG emissions and energy use related to agriculture at a national scale and high resolution has not been done before. The approach we describe here is based upon a link between operational data sourced from gross margin (GM) handbooks and life cycle assessment (LCA) process data. We have collected and processed these datasets to produce a comprehensive database of typical agricultural operations covering 72 commodities grown in 42 regions across Australia. We have also created a system that estimates the GHG emission and energy use patterns of the aforementioned commodities using the best available LCA process data. To capture GHG emissions of non-domestically produced fertiliser, we queried the United Nations Commodity Trade Statistics Database (COMTRADE) to analyse the fertiliser and pesticide import patterns for Australia between 2000-2010. This analysis determined the average country energy-mix for fertiliser and pesticide manufacturing and allowed linking the associated GHG emissions to Australian agricultural production. Finally we spatialised agricultural operational data, emissions and energy use at the national scale using the latest Australian Land Use Map (2005/06). Our findings suggest that in 2005/06 greenhouse gas emissions related to Australian agricultural production equate to a total of 95.8 Mt CO-e using 75.7 GWh of energy. According to our results 29.4% of these emissions come from sources that were categorised as non-agricultural (e.g. industrial processes or energy use) in the Australian National Greenhouse Gas Inventory (NGGI) 2006. We find that the provision of transparently modeled GHG emissions and having them linked to a spatially explicit component helps identifying new opportunities for emission reduction and facilitates an assessment of their effects. For example, our findings suggest production of ethanol from corn stover and sugarcane bagasse could have avoided 4.37 Mt CO-e emissions (4.56% of total) without affecting food production.

In the face of the unfolding climate crisis, the role and importance of reducing Greenhouse gas (GHG) emissions from the building sector is increasing. This study investigates the global trends of GHG emissions occurring across the life cycle of buildings by systematically compiling life cycle assessment (LCA) studies and analysing more than 650 building cases. Based on the data extracted from these LCA studies, the influence of features related to LCA methodology and building design is analysed. Results show that embodied GHG emissions, which mainly arise from manufacturing and processing of building materials, are dominating life cycle emissions of new, advanced buildings. Analysis of GHG emissions at the time of occurrence, shows the upfront ‘carbon spike’ and emphasises the need to address and reduce the GHG ‘investment’ for new buildings. Comparing the results with existing life cycle-related benchmarks, we find only a small number of cases meeting the benchmark. Critically reflecting on the benchmark comparison, an in-depth analysis reveals different reasons for cases achieving the benchmark. While one would expect that different building design strategies and material choices lead to high or low embodied GHG emissions, the results mainly correlate with decisions related to LCA methodology, i.e. the scope of the assessments. The results emphasize the strong need for transparency in the reporting of LCA studies as well as need for consistency when applying environmental benchmarks. Furthermore, the paper opens up the discussion on the potential of utilizing big data and machine learning for analysis and prediction of environmental performance of buildings.

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

In persuasion of global commitment of the country on reduction of Greenhouse Gas (GHG) emission, India’s ‘National Mission on Sustainable Habitat’ has included promotion of energy efficiency in residential and commercial sector and has envisaged that energy use in buildings varies significantly across income groups, building construction typology, climate and several other factors. Though substantial energy savings can be achieved in the housing sector through implementation of various carbon mitigation options, it was stated that the incremental cost of implementing energy efficient measures is estimated to vary between 3 and 5% for residential houses. The challenge before the engineers, architects and other professionals associated with building construction sector is to find out appropriate technologies that will ensure reduction of GHG emission without increasing cost of construction. As majority of construction in government sector will come from construction of small residential house belonging to Economically Weaker Sections (EWS) as part of government’s commitment to provide housing for all by 2020, assessment of GHG reduction potential of various cost-effective construction technologies is very essential to provide guidance to the stakeholders. This paper has surveyed various prevalent construction technologies in different parts of the country, analyzed the cost and embodied GHG emission for construction of the building envelope by collecting data through extensive search of literature and information obtained from construction sites. It has been found that there is ample scope of adoption of location-specific, cost-effective and eco-friendly construction technologies for construction of houses for EWS which are capable of reduction of GHG emission without any increase in cost of construction. The technologies can meet the commitment of the country at international level on reduction of GHG emission without any extra burden to state exchequer.

The construction of tall buildings generates a high spatial and temporal concentration of greenhouse gas (GHG) emissions. Research has shown that as building height increases, more resources per floor area are required to withstand the increasing effects of wind and earthquake loads. This has major implications for the environmental performance of tall buildings since the embodied GHG emissions (EGHGE) of structural systems tend to represent the greatest portion of the life cycle GHG emissions of tall buildings. In mitigating the effects of climate change, life cycle assessment (LCA) has been proposed as an early stage design tool to facilitate the choice of structural systems for tall buildings. However, international standards on LCA do not specify which of the three main life cycle inventory (LCI) approaches to use - process analysis, environmentally-extended input-output analysis or hybrid analysis. The aim of this paper is to evaluate the influence of LCI approaches on the choice of structural systems for tall buildings to minimise their embodied GHG emissions.The effects of LCI approaches on the choice of structural systems for tall buildings are evaluated using 10 tall buildings, ranging in height from 10 to 50 storeys, parametrically designed using finite element modelling. Two alternative structural systems are proposed and various LCI approaches are used to compare their EGHGE. The paper demonstrates that varying the LCI approach can significantly influence the values of EGHGE of structural systems for tall buildings by up to 116%. Notably, the paper demonstrates that, in minimising EGHGE, the adopted LCI approach can influence the choice of structural systems for tall buildings. The findings of this study confirm the need for clarity, transparency and comprehensiveness in the use of LCI approaches for comparative LCA studies, particularly in the structural design of tall buildings.

Addressing the social life cycle inventory analysis data gap: Insights from a case study of cobalt mining in the Democratic Republic of the Congo

Effect of a one-dimensional approach in LCA on the environmental life cycle impact of buildings: Multi-family case study in Flanders