Feasibility of converting Hong Kong's restored strategic landfill intoclean energy facility

Abstract

Closed landfills possess vast open space which could only be lightly developed due to environmental concerns. Renewable energy production is one of the few beneficial and viable uses. This paper presents a study on the feasibility of converting Hong Kong’s restored strategic landfill into a clean energy facility. South East New Territories (SENT) landfill has been chosen for study due to its impending closure, its proximity to energy demands and expected restored area at approximately 60 ha. Given the location constraints, photovoltaic (PV) solar farm was found to be the most viable technological option among all available renewable energy choices. A review of literature has revealed that there are overseas examples of using ex-landfill sites for PV solar farms in the developed countries including the US, Germany, France, Italy and Korea. Different PV systems have been explored, with C-Si, CdTe, A-Si and CIGS PV panels being shortlisted for further investigation. The site characteristics have also been studied and solar resource was found to be adequate. The renewable energy production from abovementioned options has been estimated to be 81.9, 61.9, 44.3 and 68.8 million kWh respectively. The environmental performance of the hypothetical landfill based PV systems were evaluated through a life-cycle assessment. C-Si PV system has a longer payback period in terms of energy and CO2 emission. However, it outperforms the other PV options in terms of overall environmental performance over the entire life cycle. Given the long product life of PV panels, other elements including transportation, electricity system, invertors and mounting was found to be of little impact to the life cycle performance of a PV installation. The cost estimation indicates that the monetary payback period would be longer than the lifetime of all installation options. Hence, from an economic point of view, breaking even is unlikely. The findings from this study are expected to provide a preliminary concept to policy makers and environmental managers, shedding light on the implications of an alternative beneficial use of Hong Kong’s vast yet closing strategic landfills.