Construction equipment consumes a vast amount of energy, but that’s not the only thing to worry about. Manufacturing the building materials and then transporting them to the building site to be installed and constructed into the final structure all emit a great amount greenhouse gases, and take a fair amount of energy, too. The building science journal Building and Environment published a case study of a Hong Kong example to demonstrate the building construction costs in terms of greenhouse gas emissions.
Hui Yan and his collaborators aimed to calculate all the greenhouse gas emissions for a building’s construction. Independent studies have been done on energy in the manufacture of building materials, transportation of those materials, and greenhouse gas emissions in building construction, but none have taken all of these aspects into consideration of the whole picture.
Manufacture of the building materials is just one of six greenhouse gas contributors identified for this study. The others are the transportation of building materials and equipment to the site, energy use of the construction equipment, transportation of workers, and final disposal of the construction waste.
Half of the world’s energy goes into buildings throughout their lifetime, from construction, through use, and finally demolition. They also contribute almost half of the world’s carbon dioxide emissions. Transporting the materials to the site constitutes 6-8% of total greenhouse gas emissions for a project.
Construction is one of the largest consumers of raw materials. In fact, 25 % of the world’s timber goes to construction efforts. Nevertheless, the manufacture of concrete and reinforced steel account for 94-95% of the greenhouse gas emissions for construction materials.