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Assessing the feasibility of cogeneration retrofit and district heating/cooling
networks in small Italian islands

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M. Beccali , G. Ciulla , B. Di Pietra , A. Galatioto , G. Leone , A. Piacentino 1,*
* Corresponding author. Email: piacentino@dream.unipa.it

1 Dpt. of Energy, Information Engineering and Mathematical Models,
University of Palermo, Viale delle Scienze, Building no. 9, 90128, Italy;

2 ENEA, Unità Tecnica Efficienza Energetica, Via Anguillarese 301, 00123, Rome, Italy

Email addresses: ciullaina@dream.unipa.it; biagio.dipietra@enea.it;
giuliana.leone@dream.unipa.it; alessandra.galatioto@dream.unipa.it;

ABSTRACT
Sustainability of energy supply strategies in small islands has been emerging as a severe
issue, due to the large margins for improvement and rationalization of the most frequently
adopted solutions. In most of the European islands, large amounts of heat are wasted by the
operation of engine-based power plants; conversely, heat is produced by boilers (supplied by
liquid fuels) or by electric equipment for a number of different uses, like domestic hot water
production or space heating in winter. In this paper a techno-economic analysis is proposed to
assess the feasibility of CHP-retrofit of the existing power plants and the possible utilization
of the recovered heat to supply, via a district heating and/or cooling network, the energy
requests of civil energy users (both in the tertiary and in the residential sector). The analysis is
accurately performed for six islands located in Italy and characterised by different context
conditions from a demographic, geographic and climatic viewpoint, so as to get a
comprehensive understanding of the factors that favour/obstruct the economic feasibility of
the examined technical solution. As expected, due to the low “linear heat density” usually
observed in small islands and to the complex orographic profiles, the investment usually
resulted “far from being attractive”; only in the case where public incentive or support
mechanism is adopted, the possible integration of the existing power plants with heat recovery
devices and a district heating network resulted in moderately attractive, especially in the
largest examined islands due to their highest heat loads.

KEYWORDS
Cogeneration, trigeneration, residential/tertiary energy uses, load estimation, district
heating/cooling, small islands, energy analysis, economic viability.

INTRODUCTION

Sustainable energy supply in remote areas like small islands represents an emerging research
topic [1], since in many sites obsolete technologies and scarcely efficient energy uses may be
encountered. In this regard, recent studies have suggested the use of integrated approaches to
sustainability, aimed at addressing both the need for efficient energy supply and the problem
of fresh water scarcity often experienced in such remote communities [2]. Fresh water
production is prevalently achieved by Reverse Osmosis plants that consume significant
amounts of electricity eventually produced by Renewable Energy Sources (RES) [3].

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