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Building energy retrofits can reduce emissions and increase cost savings. Some retrofits that can deliver higher emissions savings are not popular due to a lack of economic justifications. Financial incentives can be used to change buyer perception around such retrofits. This study proposes a framework to identify the best-performing retrofit strategies for a given building cluster and the optimal incentive amounts to promote the chosen strategies, accounting for uncertainties, stakeholder priorities, and budget constraints. The proposed framework was demonstrated using a case study complemented with policy insights. Life cycle cost savings and capital cost significantly impact retrofit purchase decisions. Case study results showed that retrofitting houses heated with electricity can produce significant cost savings. However, adopting energy-conscious behaviours in houses heated with natural gas and injecting renewable natural gas into the gas supply can produce two times more emissions savings achieved by any retrofit strategy applied to an electrically heated house. This indicates the need for adopting performance-based incentives over the prescriptive approach to reward occupant efforts in addition to asset performance. Despite potential life cycle cost savings, incentives must be complemented with low-interest loans to promote retrofit strategies carrying higher capital costs. [ABSTRACT FROM AUTHOR]

Bridges reinforced with superelastic shape memory alloys (SMAs) demonstrate improved performance under earthquake excitations. In general, the capital investment for a bridge reinforced with SMAs is higher due to their high cost and special workmanship requirement. However, when accounting for postearthquake repair and maintenance costs and environmental impacts, SMA-reinforced bridges can deliver significant economic and environmental advantages over conventional structures in the long run. Based on a life cycle thinking–based decision support framework developed in a companion paper, this study thoroughly evaluated the life cycle seismic performance of a bridge reinforced with an SMA considering three different reinforcement configurations. Fragility analyses were conducted for each reinforcement configuration of the SMA-reinforced concrete (RC) bridge to assess its seismic vulnerability. A life cycle cost (LCC) assessment was performed to determine the economic impacts during their service life. Additionally, cradle-to-grave life cycle assessment (LCA) was done using SimaPro to assess the environmental impacts. Using the outcomes of the these assessments, the overall life cycle performance of the novel bridges was compared with a similar bridge reinforced with conventional steel. The results showed that the SMA-reinforced bridges presented a better seismic life cycle performance compared with a conventional RC bridge from a seismic performance and economic perspective. However, the conventional bridge showed a better overall score from an eco-friendly approach. [ABSTRACT FROM AUTHOR]

Bridges are an integral part of a country's transportation infrastructure system. Earthquake-induced damages to bridges could result in fatalities and injuries, disturbances to the transportation infrastructure system, and incur significant repair costs. Furthermore, bridges must stay functional following an earthquake to maintain the continuity of transportation. Thus, innovative high-performance materials in the critical regions of structures and/or structural systems must be used located in regions of high seismic activity to mitigate the impacts of earthquakes. Despite having a higher seismic resilience, these structures, in general, tend to require a greater capital investment as a result of utilizing expensive material and special workmanship. However, when accounting for the postearthquake repair and maintenance costs, these seismically enhanced bridges can deliver significant cost advantages over conventional structures in the long run. Even so, the outcomes depend on the frequency and severity of the seismic damage, the lifespan of the bridge, the cost of materials, and the embodied emissions of the structures. To ensure better overall results, the cost–benefit analysis should be done with a life-cycle thinking perspective when comparing and making a decision related to multiple bridge systems. In this regard, a decision framework is developed to evaluate the overall life cycle performance of such a novel bridge, using fuzzy logic to integrate uncertainty. The proposed framework will assist engineers and the construction industry as a whole in making informed decisions regarding bridge infrastructure planning under dynamic conditions. [ABSTRACT FROM AUTHOR]

Energy performance contracts (EPC) can address economic sustainability challenges associated with residential energy retrofitting projects, including funding limitations, poor quality of project delivery, and landlord-tenant dilemma. Literature has overlooked the impact of weighted average cost of capital (WACC) and funding sources in EPC planning. However, the WACC, stakeholder priorities, and uncertainties can alter the project outcomes. This study proposes a Monte-Carlo simulation based non-linear multi-objective optimization approach to address the aforementioned challenges. A case study conducted in British Columbia indicated that the maximum overall project profitability can vary between $18,035 and $20,626 with decision priorities. The overall project profitability can vary over 9% due to uncertainties. The project profits can change over $3000 due to changes in the WACC. These observations confirmed the criticality of accounting for WACC, stakeholder priorities, and uncertainties in EPC planning. The risk of compensating for the performance compromises and profits increases simultaneously for the energy services company with the increasing contract periods, while it is inverse for the owners. Therefore, the contract period must be decided considering the profit expectations and risk tolerance of the stakeholders. Extended contract periods allow lower capital contributions from the building owners, potentially solving the principal-agent disputes in rental buildings. [ABSTRACT FROM AUTHOR]

• A retrofit selection strategy employing economic and environmental decision criteria was proposed. • Building energy retrofits were evaluated through a life cycle thinking approach. • Retrofits with operational emissions savings may not be beneficial when considering life cycle impacts. • Energy mix and the heating system of the house greatly impact the effectiveness. • Retrofit selection changes with stakeholder priorities on environment and economics. Improving the energy performance of buildings has been a much-discussed topic over the past few decades. With the current focus on climate change mitigation, emissions reduction has also come to the forefront of this discussion. Retrofitting is an option to improve the energy and emissions performance of buildings. However, in the residential building stock, retrofit planning for existing buildings faces many complexities due to variations in climatic conditions and macro-environment as well as the presence of multiple stakeholder groups. Thus, in identifying solutions, it is necessary to take a holistic perspective that covers these different dimensions. In this paper, commonly used building energy retrofits were evaluated through a life cycle thinking approach. The performance of various retrofit options applicable for single family detached housing were evaluated using the HOT2000 energy simulation software package under the varying climatic conditions and energy supply scenarios across Canada. The retrofits were evaluated in terms of the additional investment, energy use and cost reduction achieved over the life cycle, and life cycle emissions reduction. The findings indicate that the provincial energy mix and the heating system of the house (i.e. electric or natural gas) play a major role in determining the effectiveness of a retrofit, and this "effectiveness" changes at different stakeholder levels. However, not all retrofits that reduce emissions make economic sense and vice versa when life cycle thinking comes into play. The findings will be useful for building owners and occupants as well as for policy developers and other decision makers interested in demand side management. [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]