Technical–Financial Feasibility Study of a Micro-Cogeneration System in the Buildings in Italy

Abstract

The current global context, marked by crises such as climate change, the pandemic, and the depletion of fossil fuel resources, underscores the urgent need to minimize waste. Cogeneration technology, which enables simultaneous production of electricity and thermal energy from electricity generation waste, offers a promising solution to enhance energy efficiency. Its widespread adoption, particularly in the European Union, where several cogeneration systems are in place, demonstrates its growing popularity. Italy alone has 1865 high-efficiency cogeneration units, contributing significantly to total cogeneration energy generation. Micro-cogeneration, specifically, has attracted attention for its potential to reduce energy waste and environmental impact. This study focuses on assessing the technical and financial feasibility of a micro-cogeneration plant using natural gas-fuelled internal combustion engines, considering different scenarios of plant operating strategies in order to optimize energy production, minimize waste, and mitigate environmental footprints associated with conventional methods. Additionally, it provides valuable guidance for policymakers, industry stakeholders, and decision-makers invested in sustainable energy solutions. By advancing micro-cogeneration technology, this study aims to promote a more sustainable and environmentally conscious approach to energy production. The methodology applied is based on the development of a numerical model via RETScreen Expert 8 and it was calibrated with one-year energy bills. The study was performed by focusing on the analysis of the annual energy savings, greenhouse gas emission savings, tonnes of oil equivalents savings, and financial parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), Profitability Index (PI) and Payback time (PBT). The results show, using a micro-cogeneration system in a big complex of buildings, that the financial parameters can continually increase with the plant’s capacity with the electrical load following, but with a loss of the recovered heat from the cogenerator because it may reach values that are not necessary for the users. When the thermal load variation is much more significant than the electrical load variation, it will be useful to design the plant to follow the thermal load variation which allows the full utilization of the thermal and energy production from the plant without any waste energy and choosing a system capacity that can optimize the energy, emissions and financial aspects.