Cost optimality – brake or accelerator on the way towards nearly zero energy buildings

Panel: 5B. Cutting the energy use of buildings: Policy and programmes

This is a peer-reviewed paper.

Authors:
Klemens Leutgöb, e7 Energie Markt Analyse GmbH, Austria
Lorenzo Pagliano, End-Use Efficiency Research Group, Politecnico di Milano, Italy
Paolo Zangheri, End-Use Efficiency Research Group, Politecnico di Milano, Italy

Abstract

Art. 5 of EPBD recast requires EU Member States to take into account cost optimality when defining energy performance requirements taking into account initial investment cost, running cost and replacement cost over the life-cycle of a building. In March 2012 the Commission published the Delegated Act No 244/2012, in which the methodological approach of cost optimality calculations as to be applied under the EPBD is described. Although this regulation includes harmonised standards for some important input parameters, it leaves considerable degree of freedom to the Member States for selecting input parameters according to their choice.

This background given, calculations on cost optimality play a crucial role in setting the energy performance levels in the Member States and may show up as brakes or accelerators on the way towards nearly zero energy buildings. Based experience gathered in life-cycle cost assessment of buildings and on selected examples of cost optimality calculations under the EPBD regime the paper analyses – in a first step – the impact of the most important input parameters on the results.

In a second step an approach of a quick “top-down” plausibility check of cost optimality calculations is developed. This approach aims at increasing transparency of cost optimality calculations and follows several assessment steps “from general to particular”, as follows:

• Check 1: Plausibility of the shape of the cost curve (e.g. flatness resp. steepness in certain energy performance areas)

• Check 2: Plausibility of the “spread”, i.e. the ratio between different input parameters (e.g. discount rate compared to energy price increase; investment cost related to quality and life-time etc.)

• Check 3: Plausibility of selected – i.e. the most important – input parameters

The paper concludes that cost optimality assessments usually suggest that considerable tightening of minimum energy performance requirements can be argued also from an economic point of view.