Life-Cycle Analysis of Building Retrofits at the Urban Scale—A Case Study in United Arab Emirates

摘要

A consensus is forming among experts that the best way to achieve emissions’ reduction in the near and mid-term is increasing the demand-side energy efficiency—this is especially true in developing countries where the potential for demand reduction is significant and achievable at relatively lower cost. Enhanced energy efficiency also reduces energy costs and can result in a financial benefit to end-users, if the life-cycle value of energy savings offsets the upfront cost of implementing the measure. At the same time, reducing energy demand translates into lower pull for fossil fuel import and supply/distribution capacity expansion. An ideal candidate for the implementation of demand-side energy efficiency measures is the building sector, since it contributes to a large extent to the total amount of greenhouse gases (GHGs) emitted worldwide. In most developing countries, the contribution of the building sector to the total national GHG emissions is significantly higher than the worldwide average. This is in part due to the lower level of industrial activity. Other drivers of the high emissions of the building sector are the inefficiency of the envelope and technical systems of the existing buildings, as well as harsh climatic conditions requiring the use of energy intensive air-conditioning equipment. The United Arab Emirates (UAE) currently have the highest ecological footprint per capita in the world. The Emirate of Abu Dhabi, the focus of this study, can be expected to have a footprint that is even higher, being the largest economy and the major oil producer among the seven Emirates. In addition to the environmental consequences of unrestrained energy consumption, the fact that energy prices are heavily subsidized in Abu Dhabi results in a significant financial burden for the government. In the UAE and the Emirate of Abu Dhabi, the air-conditioning load in buildings is the ideal target for demand-side management because it constitutes more than 60% of the total energy consumption. However, many sources of uncertainty still remain. How should we assess the life-cycle cost/benefit of candidate demand-side interventions? Which ones to choose in order to maximize national utility? This study will start to answer those questions by using a detailed engineering model of a typical Abu Dhabi building as specified by the Emirate’s Urban Planning Council. Using the model building as a baseline, we then proceed to evaluate the energy impact of different retrofits through numerical simulation. We present a novel Marginal Abatement Cost Curve (MACC) for the Emirate of Abu Dhabi focusing exclusively on demand-side measures having an impact on the air-conditioning load. A surprising number of the abatement levers analyzed in this study exhibit a positive net present value (NPV), if the cost-reflective price of electricity is used for the life-cycle assessment.