Promotion of polygeneration for buildings applications through sector- and user-oriented “high efficiency CHP” eligibility criteria

The eligibility criteria adopted to assess polygeneration plants as “highly efficient” can play a determinant role in favouring or discouraging the market growth of polygeneration systems, especially for buildings applications where economic viability is often more difficult to achieve. Based on the current European framework, in this paper the opportunity to adopt sector- and user-oriented criteria is discussed. After having identified three buildings with different uses (a large hotel, a hospital and an office building), the optimal lay-out and operation strategy of a polygeneration plant serving each building is determined; then, ex-post processing of economic and energetic results is used to assess at what extent sector-oriented eligibility criteria would be justified and could contribute to a more effective promotion of polygeneration. Finally, for a centralized polygeneration system serving the above three buildings, a particular context condition is analysed, that is the availability of free space to install a large heat storage; it will be shown that this condition moderately influences the amount of electricity assessed as “CHP electricity” and then eligible to obtain “guarantee of origin” and dispatching priority.