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CONCLUSION
In this paper an analysis was carried out for a number of small Italian islands, aimed at
assessing the viability of heat recovery from the existing diesel-engine based power plants
(currently operated, very inefficiently, in power-production-only mode) and the possible
distribution of heat to supply energy loads of both residential and centralized/punctual users.
The six examined islands differ by the number of inhabitants, the climatic conditions, the
incidence of touristic fluxes on the energy loads and several other factors. Detailed
simulations were made, based on a number of scenarios as concerns the energy loads to be
covered via the distributed hot/warm or cold fluids and the contribution to the coverage of
connection costs; optimal paths for the main and branch lines were determined, based on the
linear heat density in the most densely populated areas. Once conducted accurate cost
analyses, synthetic economic indicators were derived to assess the viability of the “CHP
retrofit + DH network installation” plans. As expected, even for the most promising scenario
for each examined island, the proposed solution was far from economic viability, especially
due to the extremely low heat density which is, in its turn, induced by the prevalence of “non-
hydronic” space heating and cooling systems in residential buildings. In case of inclusion, in
the economic analysis, of possible incomes from support mechanisms such as White
Certificates for cogeneration and eventual grants covering a fraction of the DH network
purchase and installation cost, moderate feasibility could be achieved in some cases, although
the investment remained scarcely attractive as proven by the long payback periods. A high
number of permanent inhabitants resulted to be the factor most favouring the viability of the
examined schemes, while the climatic conditions of the site appeared to play only a secondary
role. Of course, the results are highly sensitive to specific conditions such as, for instance, the
distance between the power plant and the most densely populated areas.

CONTRIBUTION OF AUTHORS

As concerns the contribution to the work, Dr. Leone Dr. Galatioto Dr. Ciulla have performed
the territorial analysis of the islands, collected and organised information related to the end
uses per categories and built the dynamic models for the energy loads evaluation. Prof.
Piacentino defined the scenarios and designed the CHP retrofit and DH network solutions,
sizing the plant components, identifying the network geometries and sizing the lines, and
performing all the energo-economic analyses. Dr. Di Pietra managed the information flow
between the research team and electric utilities and public authorities. Prof. Beccali
coordinated the whole project and supervised all the phases of the work.

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