Tihomir Tomić

Municipal solid waste system analysis through energy consumption and return approach

Inappropriate waste management and poor resource efficiency are two of the biggest problems which European Union is trying to solve through Landfill Directive, Waste Framework Directive and Circular Economy Package by increasing recycling and reuse and reducing waste disposal. In order to meet set goals, new European Union member states must quickly change national legislature and implement appropriate solutions. In the circumstances of strong EU resource and energy dependence, decision makers need to analyse which of the considered waste management systems leads to higher overall benefits ie. which is more sustainable. The main problem in this kind of analysis is a wide range of possible technologies and the difference in inputs and outputs. Sustainability of these systems is analysed through single-score LCA based assessment, using primary energy used to produce materials and energy vectors as a common measure. To ensure reliable results, interoperability between different data sources and material flows of waste and its components are monitored. Tracking external and internal material, and energy flows enable modelling of mutual interactions between different facilities. Resulting PERI, primary energy return based index, is used for comparison of different waste management scenarios. Results show that time and legislation dependent changes have great influence on decision making related to waste management and interconnected systems.

Influence of legislative conditioned changes in waste management on economic viability of MSW-fuelled district heating system: Case study

District heating systems represents one of the ways by which the European Union is trying to reach set goals in energy efficiency and security field. These systems allow the use of different energy sources including local energy sources such as waste and biomass. This paper provides economic viability assessment of using these fuels in the district heating system. Economic evaluation is based on regression analysis from data of existing plants and on the locally dependent data. Some of parameters that are dependent of local parameters are price and available fuel quantity, therefore these values are separately modelled; biomass as a function of location of the plant while municipal waste as a function of location and the time changes in waste quantity and composition which depend of socio-economic trends and legislation. This methodology is applied on the case of district heating plants in the City of Zagreb where internal rates of return are calculated for four considered scenarios. Results indicate that waste powered plant can improve its profitability by co-combusting other local wastes while economic viability is achieved by introduction of region wide waste management system. Reducing plant capacity, based on prognosis of waste generation, showed that these plants can be competitive with biomass plants.