Economic analysis of small size gas turbine based chp plants in the present Italian context

The paper deals with the economic performance assessment of CHP plants based on small size Gas Turbine (1-6 MWEL) taking the present Italian regulatory framework and economic context into consideration. From January 2011, the regulatory framework and, consequently, the incentive mechanism is radically changed. The "High Efficiency Cogeneration" concept has been introduced and requirements to be fulfilled by a CHP plant to obtain incentives defined. Such requirements are essentially related to the achievement of a threshold value of the Primary Energy Saving (PES) index. According to the new regulatory framework and taking the present national scenario into consideration (fuel and electricity prices, cost of money, etc.), a techno-economic analysis aimed at assessing the viability and suitability of installing GT based small CHP plant has been carried out. The convenience of the investment has been assessed by comparing costs incurred by installing and operating the CHP plant with those related to the purchase of the required electric power and the production of heat in a fuel fed boiler. Several CHP plant arranged with commercially available MW-class GTs have been examined. Results show that plants in the range of 1.5-6 MWEL can lead to relevant cost savings. For lower sizes, the investment effectiveness has to be carefully checked.