While many cities in Europe and in the world have issued climate change policies and set targets for reduction of CO2 emissions, their implementation in urban planning practice remains a major challenge. Devising effective decision systems which support CO2 emissions reduction demands a systems approach which enables different actors -policy makers, planners, engineers, consultants, and inhabitants- to correlate a diversity of problems, spanning across distinct domains and geographic scales. The technological approach of SEMANCO is based on the integration of energy related open data structured according to standards, semantically modeled and interoperable with a set of tools for visualizing, simulating and analyzing the multiple interrelationships between factors determining CO2 production. A Semantic Energy Information Framework (SEIF) will be developed to model the energy-related knowledge planners and decision makers need. The tools interoperating with the framework will support systems innovation and include available technologies, enhancements to existing open source platforms, and new technological solutions. SEMANCO will carry out an analysis requirements to support the application of the tools by the different stakeholders involved in energy related urban planning. The development of the tools and methods will be informed by three case study scenarios in Spain, UK and Denmark which will cover three geographical scales -neighbourhood, municipal and regional- including both existing and new urban areas. The case studies will identify the relevant indicators and the interrelationship between factors contributing to CO2 production in the analyzed urban areas. Based on this analysis, tools and methods will be developed as the project progress. Their application within the cases of study will demonstrate quantifiable and significant reduction of energy consumption and CO2 emissions achieved through ICT and will make it possible to assess their social impact.