Green building and the way the build environment interfaces with urban structures and services have become significant levers of action for cities to reduce greenhouse gas emissions and are perceived as climate change leaders. Against this background, this chapter investigates conditions and drivers behind innovations leading towards green building in selected city regions. It embeds urban energy transitions within the recent literature on sustainability transitions that pays attention to the spatial dimensions of green transformations, including regional variations and multi-scalar linkages within and between cities and regions. Further, it places particular emphasis on the role of both individual and institutional actors in these changes. As such, knowledge transfers and learning processes amongst practitioners, experts and decision makers, both in the building sector and at the urban policy level, are considered to be central to understanding green building innovations and developments in city regions.

Methodologically, the chapter introduces and discusses two specific tools: the World Café and Delphi approaches that seem particularly well suited for knowledge generation and data collection of complex and multi-actor processes common in sustainability science. Based on practical experiences, the benefits and challenges of the methods are critically discussed. Their potential contribution to critical reflection is also outlined. In the emerging field of green building and related policy, as well as societal and technological innovations, they have shown both their efficiency in exploring new actor constellations and policy arrangements and their potential for initiating mutual learning processes between researchers and practitioners, as well as amongst practitioners themselves.