Optimization of CO2 emissions in the design phases of urban planning, based on geometric characteristics: a case study of a low-density urban area in Spain

Abstract

When environmental impact analysis is included in the design phase of engineering projects, this lowers the cost of strategic actions that must be performed to minimize possible environmental damage in later project phases (Construction Process Stage, Use Stage, and End-of-Life Stage). In the case of family housing, efforts to optimize energy consumption will not be successful if initial urban planning stages are not taken into account. The objective of this research was to use Life Cycle Assessment (LCA) as a method of evaluating the environmental impact of urban planning. For a surface area of 100,000 m2, six housing development alternatives were analyzed for the following housing profiles: (i) single-family detached house; (ii) single-family semi-detached house; and (iii) high-rise apartment buildings of 40, 20, 10, and 5 floors. The results for this case study indicated that in the building construction stage, the activities that produced the greatest environmental impact were those related to the foundation, frame elements, and siding of the buildings. More specifically, these activities were responsible for 55–68 % of the CO2 emissions produced during this stage. In contrast, in the urbanization phase, the most harmful activities were linked to earth-moving and paving, which generated 63–75 % of the emissions in this stage of the project. Furthermore, this study highlights the importance of using steel and cement with a low environmental impact as well as of creating green spaces with an environmentally friendly design. The results obtained show that the steel and concrete used in the building construction stage were responsible for 30–52 % of all of the CO2 emissions during this phase.