Production of renewable energy on closed landfills to compensate for biogas emissions: A case study of the Valdina landfill (Messina, Italy)

The contribution of integrated municipal solid waste (MSW) management systems to greenhouse gas emissions is not negligible, even though it is moderate compared with other anthropogenic activities. The main emission from landfills that accept biodegradable MSW is methane that escapes from the biogas collection system. Such emissions are partially compensated if the collected biogas is exploited for energy production. Further compensation measures would also increase the overall sustainability of the landfill site. This study analyses the possibility of exploiting closed landfills to produce energy based on the case study of the Valdina landfill (Messina, Italy). Two possible scenarios are presented: the installation of a photovoltaic system and the cultivation of giant reed (Arundo donax L.) to be used for energy production through combustion. The results of a preliminary experimental activity are presented for the second scenario. The findings demonstrate the possibility of using the leachate produced in the landfill for irrigation purposes. For each scenario, the costs, potential energy production rate, avoided emissions and issues related to the integration of energy production with the landfill aftercare are evaluated. The presented results suggest that the cultivation of giant reed is the best option, especially during the early post-closure period, in terms of investment (18,000 € against 8,300,000 €), high production yield in the Mediterranean climate, simplicity of cultivation and integration with ordinary post-closure landfill management, limited cost of the energy produced (0.1€ kWh^-1 against 0.27€ kWh^-1). On the other hand avoided emissions are higher for the photovoltaic plant (27804  against 778  on an horizon of 20 years).