Abstract
This document outlines the definition, key performance indicators (KPI) and assessment criteria for the Research Centre on Zero Emission Neighbourhoods in Smart Cities (ZEN research centre). This second version of the ZEN definition builds upon version v.1.0 of the ZEN definition (1). The ZEN categories for GHG emission, energy and power have been updated after having been tested in selected pilots. In addition, a description of ZEN KPI tool and framework has been added. Finally, the ZEN categories mobility, spatial qualities, economy, and innovation have been partly updated. Over 100 people involved in the ZEN research centre have contributed to this document.