Explicit and realistic representation of heterogeneities residential demand for space heating: modelling principles and implications for national energy policies

Residential buildings sector encompasses increasing energy demand projections and large technical potentials for energy savings [Levine et al., 2007] that are mainly more cost-effective than in sectors like transportation or industry. However, the decline of main residential energy uses in France (space and water heating) is limited by market and behavioural failures, making the reach of ambitious reductions targets very unlikely without the implementation of dedicated public policies [Giraudet et al., 2009]. Moreover, prospective studies have also shown that only major technological change scenarios on heating usages for existing buildings meet overall national long-term target (carbon emissions reduction by a factor of 4 in 2050 comparing to current level) [CLIP, 2011]. On one hand, current political context is characterized by increasing public finances constraints (leading recently to the reduction of efficient refurbishment tax credit in France). One the other hand, it has been shown that residential energy savings potentials are very diverse in cost-effectiveness [Laurent et al., 2009] and technological learning potential [Weiss et al., 2008]. Finally, recent work highlighted the importance of energy demand heterogeneity representation when studying the diffusion of energy efficient equipments [Cayla, 2009]. Previous elements draw a need for a realistic and technology rich modelling of energy efficiency potentials and related households investment decisions in response to various types of policy instruments. Such model aims at providing an efficient and realistic support for national energy policymakers, better adapted to their financial constraints and energy reduction targets than classical normative and aggregated models.