Since a Combined Heat and Power (CHP) plant can offer high economic benefits when a certain energy savings value is obtained, it is very interesting to consider the requirements foreseen by legislation to meet this target. The paper deals with an energetic assessment of eleven industrial CHP power plants, based on different prime mover technologies installed and in operation in Italy. The analysis has been carried out considering not only the nominal design data of the plants, but also experimental ones, in order to highlight their real operational performances.
The aim of the study was to compare the effects of two legislations on the calculation of the primary energy savings: the first is the Italian legislation that was in force when the power plants were designed, and the second is the current European Directive, which was issued a few years later when the plants were already in operation. The results of the study show as the subsidy mechanism introduced by the new legislation is stricter than the previous one, and could have a significant effect on the economic profitability of a cogeneration plant installation. More critical comments on the overall regulatory framework are presented in the paper.