Life Cycle Cost Analysis of rooftop gardens using openLCA

Abstract

Most innovative and eco-friendly project alternatives are rejected due to higher initial costs. This problem arises due to the general cost analysis that considers only the initial costs. It can be solved using Life Cycle Cost Analysis (LCCA) approach because LCCA helps the decision makers to select the project alternative with more economic benefits by considering the costs incurred in it throughout the life cycle. In this paper, the life cycle cost analysis of the rooftop garden was carried out and compared with the conventional roof using openLCA software. The rooftop garden includes many environmental benefits such as the reduction of the urban heat island effect, reduction of noise pollution, improvement in quality of air, management of surface runoff and conservation of biodiversity. Still, the use of rooftop gardens is not common in the projects due to their higher initial costs. Thus, LCCA was carried out to evaluate its economic feasibility. A model was developed using openLCA software to carry out the analysis. The costs considered in the analysis include the initial costs, maintenance costs, renovation costs and energy costs. The cost data were collected for extensive rooftop gardens laid in commercial buildings in and around Chennai city. The results indicate that the initial cost of the rooftop garden was 5.2 times higher than that of the conventional roof but due to the prolonged life period and the energy savings of the rooftop garden, the life cycle cost was 5.25% lower than that of the conventional roof.