Energy cost and discount rate influence on the optimal packages of energy efficiency measures.

The Commission Delegated Regulation No. 244/2012 supplementing Directive 2010/31/EU on the comparative methodology framework for calculating cost-optimal levels of minimum energy performance requirements enforces Member States to perform an analysis to determine the sensitivity of the calculation outcomes to changes in the energy price developments and the discount rates, as well as other parameters which are expected to have a significant impact on the outcome of the calculations. In Italy the cost optimal methodology has been performed by using a simulation tool enforced on a quasi-steady state numerical model (UNI/TS 11300) while the cost optimisation procedure is based on a sequential search-optimisation technique considering discrete options, as introduced in a previous work. Packages of energy efficiency measures giving optimal EP levels have been found for different buildings and climatic conditions. Results show that the optimal solutions are strongly influenced by energy costs of the different energy wares, and this can affect the suitable technical solutions for refurbishment. The present work is focused on the definition of different economic scenarios. The aim is to assess a wide economic framework as to determine the influence of the energy cost and discount rate on the costs/benefits analysis and how cost optimal solutions can change according to these trends. Different energy cost variations are considered for electricity and natural gas, which are the most used energy carriers in Italy. The economic framework is applied to four Italian reference buildings to emphasize its influence when different building uses and climatic boundary conditions are considered. Discrepancies in results are then discussed.