Conducting Life Cycle Assessments (LCAs) to Determine Carbon Payback: A Case Study of a Highly Energy-Efficient House in Rural Alaska

Abstract

Buildings are responsible for a large portion of global greenhouse gas emissions. While energy efficiency features can significantly reduce the greenhouse gas emissions during a building’s operational stage, extra materials and processes associated with these features typically involve higher greenhouse gas emissions during the construction phase. In order to study this relationship, a case study of a highly energy-efficient house in rural Alaska was performed. For the purposes of this case study, a theoretical counterpart home was designed that has the same interior space, but insulation values close to the code minimum requirements. Using computer simulations, a Life Cycle Assessment (LCA) was performed for the case study home as well as its conventional counterpart. The extra greenhouse gas emissions associated with the construction of the case study home were compared to the annual savings in greenhouse gas emissions achieved thanks to the energy efficiency features, and carbon payback was calculated. The carbon payback was calculated to be just over three years, which is only a small fraction of the life of the building. The results of this study show that despite higher greenhouse gas emissions during the construction phase, highly energy-efficient homes can play an important role in addressing climate change.

Strategies to Reduce the Impact of Resource Consumption in the Ghanaian Construction Industry

“…To lessen the effects of resource use, a variety of measures can be implemented. These can have an impact on the interconnected variables of material use, inherent energy and pollutants, infused water, and landfill waste (Alghamdi et al, 2019;Hossain & Marsik, 2019). Unquestionably, repurposing and renovating existing structures and infrastructure to minimize demolition and new development should be explored (Pullen, 2010a).…”

“…Steel contains roughly 32 MJ/Kg of embodied energy, whereas cement has about 7.8 MJ/Kg (Lomite & Kare, 2009). The largest carbon dioxide-producing substance is cement, and a large amount of carbon dioxide is created during the production and transportation of building materials (Hossain & Marsik, 2019). Annual cement output is expected to surpass 5 billion metric tons by 2050, resulting in roughly 4 billion tons of carbon dioxide (CO2) emissions (Ding et al, 2019;Liu & Gao, 2016).…”

“…Even yet, the only method to cut down on building materials used is to recycle and reuse them. In the stage of recycling and reusing construction materials, several trends and regulations have been adopted (Alghamdi et al, 2019;Hossain & Marsik, 2019).…”

Life-Cycle Assessment of Alternative Envelope Construction for a New House in South-Western Europe: Embodied and Operational Magnitude

“…Studies covering cold climate houses in developed countries have concluded that the operational phase has a preponderant weight in the total life-cycle of the building [1,10]. Moreover, studies of conventional buildings in different countries (Sweden [11], Kazakhstan [12], Alaska, USA [13], Spain [14], Portugal [15]) have showed that operational energy is dominant, representing 60-90% of the total environmental impacts. Thus, reducing heating and cooling is essential.…”

The Impact Assessment of Campus Buildings Based on a Life Cycle Assessment–Life Cycle Cost Integrated Model

“…At the same time, regional characteristics should be considered in the selection of building materials to avoid transferring the environmental impact of the construction phase to the construction operation phase. Some scholars have compared building materials [26,[57][58][59][60][61][62][63][64][65], and some scholars have considered the influence of the external environment when evaluating building materials [13,20,21,66] These studies can provide a reference for building designers to choose building materials.…”