Wuppertal Institute for Climate Environment Energy has been established in 1989 as a corporation fully owned by the German federal state of North Rhine-Westphalia. Wuppertal Institute is one of the largest think tanks for sustainability in Europe. Its work is dedicated to ecology and its relationship to economy and society. The institute supports the development of models, strategies and instruments to support a sustainable development at local, national and inter-national levels. The research explores and initiates technological and social innovations aiming at decoupling the use of natural resources from economic growth. Wuppertal Institute has a staff of around 140 persons working in four research groups and the UNEP Collaborating Center on Sustainable Consumption and Production (CSCP). Besides broad working experience on the German national level and for international Institutions such as UNEP, UNFCCC, the World Bank, the ILO and others, the institute has a long record of consultancy and policy advice for the European Commission and the European Parliament as well as for various national authorities. Wuppertal Institute has been contributing to and co-ordinating several EU studies. For its applied sustainability research, Wuppertal Institute takes an interdisciplinary and applied approach and working towards systems understanding. Technical, ecological, political-administrative and socio-economic aspects are covered by the research work of the Wuppertal Institute. Work of the different research groups of Wuppertal Institute in the field of energy efficiency is closely inter-linked, and several projects are carried out in co-operation between the different research groups. The Research Group 2 Energy, Transport and Climate Policy of the Wuppertal Institute provides research on path-ways and instruments for attaining a sustainable energy system. By using a holistic systems approach, interdependencies between the supply-side and end-use of energy are explicitly taken into account. The research aims at taking advantage of existing market conditions and political arrangements while exploring further possibilities of improvement. Emphasis is put on specifically designed approaches to overcome the numerous barriers in order to pave the way for promising initiatives of energy efficiency and clean energy supply. Wuppertal Institute has considerable experience with the analysis of en-ergy efficiency and material efficiency on the supply- and on the demand-side as well as the role of the different actors involved. Furthermore, Wuppertal Insti-ute has a long record of experience with the ex-ante and the ex-post evalua-tion of energy and resource efficiency policies with a certain focus on policies and measures targeting energy efficiency as well as the design and evaluation of energy efficiency and material efficiency projects, programmes and services carried out by different policy makers or market actors. Building on this experience, Wuppertal Institute has profound knowledge and data on the technologies, costs, and behaviour of market actors in the field of energy efficiency and material efficiency. Moreover, Wuppertal Institute operates a disaggregated bottom-up energy model for scenario analysis of energy systems and greenhouse gas emissions for Germany and Europe.