**Marco Gambini, Michela Vellini, Tommaso Stilo \*, Michele Manno and Sara Bellocchi**

Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy; gambini@ing.uniroma2.it (M.G.); vellini@ing.uniroma2.it (M.V.); michele.manno@uniroma2.it (M.M.); sara.bellocchi@uniroma2.it (S.B.)

**\*** Correspondence: tommaso.stilo@alumni.uniroma2.eu; Tel.: +39-06-72597200

Received: 20 December 2018; Accepted: 18 January 2019; Published: 22 January 2019

**Abstract:** In January 2011, the introduction of high-efficiency cogeneration in Europe radically modified the incentive scheme for combined heat and power (CHP) plants. Since then, the techno-economic feasibility of new cogeneration plants in different areas of application (industry, service, residential, etc.), along with the definition of their optimal operation, have inevitably undergone a radical change. In particular, with reference to the Italian case and according to the most recent ministerial guidelines following the new EU regulation, in the event that cogeneration power plants do not reach an established value in terms of overall efficiency, their operation has to be split into a CHP and a non-CHP portion with incentives proportional to the energy quantities pertaining to the CHP portion only. In the framework of high-efficiency cogeneration, the present study compares different CHP solutions to be coupled with the paper industry that, among all the industrial processes, appears to be the best suited for cogeneration applications. With reference to this particular industrial reality, energy, environmental, and economic performance parameters have been defined, analysed, and compared with the help of GateCycle software. Among the proposed CHP alternatives, results show that gas turbines are the most appropriate technology for paper industry processes.

**Keywords:** high-efficiency cogeneration; primary energy saving; electricity from cogeneration; paper industry; GateCycle; CO2 emissions avoided
