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Sustainable built environment has been of interest to many stakeholders in the recent years. However, life cycle economic performance as one of the key dimensions of sustainability has not been sufficiently investigated for buildings constructed using off-site construction methods such as modular construction. This research has proposed a framework to benchmark the life cycle economic sustainability of single-family modular homes. First, suitable economic performance criteria were selected and suitable measurable economic performance indicators were developed under each criterion. A performance level function was established for each indicator by which all indicators can be calculated and presented by a normalized performance level that enables combining quantitative and qualitative indicators. Subsequently, a multi-criteria decision analysis-based methodology was employed to develop a set of economic sustainability indices at the criteria level and also at the overall economic sustainability performance level. To compare and contrast the developed indices of a given modular building with the performance of similar conventional buildings, suitable performance benchmarks scales were established using the data of the historical economic performances of conventional homes. To examine the application of the proposed framework, two case study modular homes in British Columbia, Canada were analyzed. The results showed that both benchmarking homes performed 'Excellent' with respect to the overall economic sustainability. However, improvements are required to enhance the economic performance with respect to a number of criteria. The proposed framework can assist the construction decision makers, developers, and contractors with making informed decisions on the selection of the construction method. Furthermore, it can be used to address the underperforming areas over the life cycle of a modular building, even if the decision on the construction method has already been made. [ABSTRACT FROM AUTHOR]

The ever-increasing anthropogenic greenhouse gas (GHG) emissions worldwide make it quite challenging to meet country-specific Nationally Determined Contributions (NDC) targets. Therefore, it is evident that the existing emissions abatement measures need to be taken a step further. Internationally Transferred Mitigation Outcomes (ITMOs) are allowed in Article 6.2 of the Paris Agreement as a cooperative approach to achieving NDC goals. There is a potential to create ITMOs between Canada and China by replacing coal use in China with British Columbia (BC)'s liquefied natural gas (LNG) supply. Replacing coal with LNG in energy generation applications is a promising approach to mitigate emissions. With global and national pressures to reduce emissions, China has created a market for LNG imports to cater to its rising natural gas (NG) consumption due to the coal-to-gas source switching strategy. However, the terms under Article 6.2 requires generated ITMOs to ensure environmental integrity, support sustainable development goals, and have a robust accounting system. Therefore, the current study aims to quantify the life cycle environmental outcomes of generating ITMOs by exporting LNG from BC to Chinese end-users while integrating uncertainties and to provide policy recommendations in adherence with the requirements of Article 6.2. Different LNG export scenarios were generated in the study and environmental impacts of each scenario were assessed and compared using a life cycle assessment (LCA) framework developed by the authors. Sensitivity and uncertainty analyses were conducted to understand the impacts created by the data uncertainties in the final result. By replacing conventional coal with NG, approximately 40–45% and 26%–32% emissions reductions can be obtainable for Chinese textile and chemical industries, respectively. The highest emissions reduction of approximately 60% was observed when coal is replaced with NG for district heating. The life cycle emissions (LCE) quantification framework provided in the study provides stakeholders with a systematic approach to determine the total GHG emissions and emissions reduction potential of different LNG export scenarios. [ABSTRACT FROM AUTHOR]

The building sector accounts for 40% of the energy use and one-third of the greenhouse gas (GHG) emissions globally. Buildings deteriorate with age, which leads to a decrease in their energy performance. Therefore, it is significant to improve the energy performance of aging building block although it is challenging. The two main decision paths for municipalities are renovation and reconstruction. This study investigated the above options for the older housing stock in a densely populated urban centre in British Columbia, Canada. A scenario-based analysis approach was taken to evaluate the life cycle GHG emissions of six different renovation and reconstruction scenarios. The total life cycle emissions were calculated for each scenario including the embodied and operational emission, and the emissions from building construction and maintenance. A BIM-LCA combined approach was used to assess the embodied GHG emissions with the SimaPro software. HOT2000 software was used to model the operational GHG emissions. The results show that in the reconstruction scenarios, around 40% of the emissions are from the material manufacturing stage. The embodied emissions generated from the reconstruction scenarios are 5–6 times higher than the renovation scenarios. The life cycle GHG emissions of the existing house can be reduced by applying renovations, with the emissions saving gradually increasing with the level of retrofitting. The passive house reconstruction scenario delivers the greatest benefit in terms of life cycle emissions reduction compared to all other scenarios. In terms of the GHG emission intensity per unit area, the newly-built houses in scenarios 5 and 6 also have lower life cycle GHG emission per square meter than the renovated existing houses in scenario 1–4 after 15 and 10 years to breakeven respectively. Based on this, it can be concluded that when considering the older existing building stock, a careful weighing of options must take place before making the decision on replacing them with new construction. However, it is also important to consider the economic and social aspects before making decisions to renovate or replace existing houses. The study outcomes will support city planners and urban development planners to make decisions on BC aging building stock development, especially in high population density neighbourhoods. • Renovation/replacement decision of aging building stock should consider lifecycle impacts. • A scenario-based approach was taken to assess overall GHG emissions of each decision for residential buildings. • Operational GHG emissions reduce with the extent of renovation while increase in embodied emissions. • The life cycle emissions of moderate to extensive renovations have similar outputs as the code-constructed new buildings. • Replacing older houses with new passive construction can significantly reduce life cycle emissions. [ABSTRACT FROM AUTHOR]

Recent studies have shown that Canada will not achieve its 2030 emission reduction targets outlined in the Paris Agreement. Canadian energy decision makers are now at a crossroad between making sound fiscal decisions and ramping up efforts to meet emission reduction commitments. Approximately 195,000 people are living in off-grid Canadian communities, with most of these communities relying on fossil-fuel based energy generation. Hybrid renewable energy systems provide a novel solution to address the high costs of off-grid energy and Canada's emission reduction targets. To address the competing stakeholder priorities in off-grid energy planning (e.g., economic, environmental, and system performance), the authors of this paper employed a generalizable combinatorial-based alternative ranking method. Alternative energy technology combinations were simulated to calculate key performance indicator values. The framework allows decision makers to identify the most feasible energy system based on their priorities. A case study was performed with the developed framework for a small off-grid community in British Columbia, Canada. The results show that feasibility of energy system configurations vary greatly based on differing decision-making priorities. The case study also confirmed that hybrid renewable energy systems have better environmental performance compared to their fossil fuel counter parts, but at a significantly higher cost. The study further confirms that the balance between environmental and economic performance of off-grid energy systems can be improved through proper component sizing, management practices, and the integration of energy storage. • Life cycle impacts need to be considered in off-grid hybrid renewable energy systems planning. • Hybrid renewable energy systems incur lower environmental impacts at higher costs. • Combining fossil fuel generators and battery banks reduces emissions at a lower cost. • Decision makers' priorities has a high impact in the ranking of energy system configurations. • The developed method accounts for different priorities in energy system feasibility assessment. [ABSTRACT FROM AUTHOR]