Management Engineering, Mai-britt Quitzau et.al Improvement of the energy performance of buildings represents an important focus area in Europe, since there is a need to reduce the heat loss from building envelopes and implementing a greater share of renewable energy. One of the major policy responses from the European Commission has been to set up the Energy Performance of Building Directive in European legislation. Although this type of regulation provides an important push towards improved building standards in Europe, it has certain limitations in terms of preparing the ground for a more fundamental break with the inertia that still exists in the building sector with regards to improvement in the energy performance of buildings. Traditional energy policy responses to lack of diffusion of technologies often rely on a too simplistic view of technology transfer, where emphasis is put on removing single `barriers' to technology take-up (Shove 1998). It is therefore argued that policy makers often fail to recognise that technical transfer represents a contextual, localised and temporally specific process, which is often governed by nonlinear processes, rather than rational and goaloriented processes (Geels 2005). This points towards a need to reframe policy initiatives in order to take the complexity of dissemination of energy efficient technologies in practice into account; acknowledging that singular instruments are seldom sufficient to boost a wider transition in building practices, since no simple cause or driver for change exists (Elle et al. 2002; Geels 2005). The aim of this paper is to explore the conditions that urban governments have for proactively promoting low energy buildings at the local scale. These conditions are explored by looking into the use of municipal planning systems to enforce higher energy efficiency standards as a potential form of experimentation in transition processes. In doing that, urban governments are pointed out as proactive agents of change at the local level; demonstrating potential transformative power with regards to climate change processes. Through a review of five case studies of municipal initiatives to promote more energy efficient buildings from different countries in Europe, the paper provides insight into how proactive urban governments engage with and navigate within different prevailing planning and regulation frameworks to promote low energy buildings. The study in this paper is based on the work carried out in the EU Concerto Class 1 project, where one aim has been to look into how energy efficient buildings have been deliberately promoted among the five participating municipalities in the project (in Denmark, Italy, Estonia, Romania and France). The study is based on a case-oriented review on proactive municipal attempts to promote energy efficient buildings through their planning practices. The caseoriented approach does not aim at providing a stateoftheart analysis of the planning and regulation systems in Europe, but at providing a more contextual understanding of the preconditions that municipalities experience, when trying to promote energy efficient settlements. The cases were strategically selected so that these represent flagships for the involved municipalities in terms of promoting energy efficient buildings. The study shows that although important instruments exist in the planning and regulation frameworks in Europe these are not always applicable for proactive municipalities that wish to more radically promote energy efficiency in local building projects. In most of the studied cases, the building regulation represents an important instrument with a high degree of legislative power. However, in several of the case studies, the building regulation is defined at the national level, which leaves the municipalities without local influence. Another important instrument is the detailed plan, which provide a great degree of freedom for the municipalities in most of the case studies. However, in several of the cases, the detailed plan does not have any legal impact, which play down its transformative powers. In most of the cases, the municipalities |