Lifecycle Analysis of Green Roofs in the Mediterranean Climate

Abstract

Buildings account for a significant amount of energy consumption and greenhouse gas emissions worldwide. Electricity and fossil fuels are currently the primary sources of energy used for cooling and heating buildings, depending on the climate and location. Both energy sources are responsible for significant greenhouse gas emissions. In contrast, plants and vegetation absorb carbon dioxide and, thus, improve the quality of air. This effect indirectly influences climate change to lower energy demands and produce additional emissions due to rising energy consumption trends. Plants also reduce the ambient temperature by providing shade on roof surfaces. Hence, the large-scale deployment of green roofs reduces energy consumption, emissions, and costs. However, green roofs also impact the overall weight of a building and require additional construction costs. Therefore, the contribution of green roofs to the various structural and thermal performances of buildings varies for extensive intensive or semi-intensive systems. These interactions warranted a lifecycle analysis to optimize the extent of green roof applications. This approach highlighted sustainability performance measures, including energy, emissions, water, and waste. The presented study addressed a lifecycle analysis of green roof deployment during a hot summer in a Mediterranean climate zone. This climate applies to many areas that benefit from warming temperatures without extreme needs for cooling or heating. The emphasis on comparing two towns within the same climate zone facilitated a more detail-oriented approach to the lifecycle analysis. The results illustrated the energy consumption and associated release of greenhouse gas emissions related to structural and roofing materials and thermal operations throughout the service life of a building. The conclusions assessed the challenges and opportunities of green roof applications on new and existing buildings.