Techno-economic analysis for the construction of a waste-to-energy power plant

Plastic is one of the most used materials in every-day life. Its implementation globally during the last century raised the standard of living of the population, thanks to its lightness, resistance, and wide range of applications. Plastic becomes waste very quickly, and its increase all over the years is a dramatic issue for the natural environment. Mismanaged plastic waste (PW) often ends in the natural ecosystem, and due to its chemical composition, thousands of years are necessary to let the PW decompose. The European Academies Science Advisory Council has drawn up the so-called PW hierarchy, where the PW management (PWM) options are listed in order of preference: reduce, reuse, mechanically recycling, chemical degradation without or with energy recovery, incineration, landfill. However, most of the time, that hierarchy cannot be followed due to the complex composition of plastic materials and economic obstacles. The manufacturing of new plastic from scratch is cheaper than from recycling. From this perspective, it often happens that thermal degradation of PW with energy recovery is the last option to avoid the PW to be landfilled. Mismanaged or landfilled PW dramatically impacts the environment, with consequences on terrestrial and marine life and land use. Three leading technologies exist for energy recovery from PW: gasification, pyrolysis, and incineration. This project thesis investigates the techno-economic feasibility for an existing thermal power plant to be converted into a waste to energy (WtE) plant. In particular, the project involves the possibility to incinerate PW that is daily produced in the nearby factories, mainly for the automotive sector. After having analysed the heat demand of the local community, a Combined Heat and Power (CHP) has been selected as a possible solution for the WtE plant. The plant’s size is designed to burn 30 000 tons of PW per year. Particular emphasis has been dedicated to the economic assessment of the project in order to verify the feasibility. Net present value (NPV) and internal rate of return (IRR) are the main parameters considered for the financial aspect. The outcomes on predicting the expected revenue calculated for different scenarios showed that the project can be economically profitable, and it can proceed to further stages. Moreover, a sensitivity analysis has been performed in order to identify the parameters that will most influence the NPV of the project. Another essential aspect that has been thoroughly treated is the environmental impact. A review of the current EU legislation has been carried out, and a Flue Gas Cleaning (FGC) equipment has been proposed. The systems proposed are reflected in the EU Implementing Decision on the Best Available Techniques (BAT) for waste incineration (WI), and therefore they are expected to guarantee the minimum environmental impact. Finally, some further proposals are presented in order to enhance the quality of this project and increase social acceptance