Integrated LCA-LCC Assessment Model of Offsite, Onsite, and Conventional Construction Systems

Abstract

ABSTRACT Greenhouse gases associated with energy extraction, production, and consumption are considered a major source of environmental pollution that has led to global warming and climate change. In Saudi Arabia, the building sector represents the largest domain of total energy consumption (roughly 80%) followed by the industrial and agricultural sectors. Furthermore, residential buildings consume about 50% of the electrical energy in the Saudi Arabia, whereby air conditioning usage represent 70% of electrical energy consumption according to Saudi’s energy efficiency centre. To reduce overall energy consumption from residential buildings in Saudi Arabia, efforts have been made in applying sustainable principles to the construction of buildings, resulting in minimizing the consumption of energy, building materials, and water compared to the conventional construction. In order to determine areas of improvement for the development of sustainable energy buildings in Saudi Arabia, this study seeks to assess the environmental impacts and economic viability of various construction systems including prefabricated and conventional ones using models for life cycle cost (LCC) and life cycle assessment (LCA).Various concrete construction systems were investigated using the developed LCA-LCC model including Siporex, insulated concrete form (ICF), clay block, concrete block, and precast concrete systems (base case scenario). Additionally, the LCA used in this study was assigned monetary values according to the market price of CO2 and then combined with the LCC. The developed LCA-LCC therefore provides information regarding the sustainability of the construction method and may assist decision makers in public sector on the selection of the best possible construction system to minimize energy consumption, greenhouse gas emission, and environmental impact while simultaneously reducing overall life cycle costs. The highest LCC was associated with construction costs, which represented approximately 55% to 58% of the whole LCC. The operation and maintenance costs of the project over a 50-year lifespan ranged between 25% and 27% of the overall LCC, while the environmental impact cost was found to represent approximately 17.0% to 18% of the total LCC. Offsite construction system was found in this study to generate the lowest embodied carbon emission; however, it was measured to have the highest energy consumption and greatest overall environmental impact.