Based on the presentation and discussion at the 3rd Winter School on Technology Assessment, December 2012, Universidade Nova de Lisboa (Portugal), Caparica Campus, PhD programme on Technology Assessment Environmental concerns over the use of fossil fuels and their resource constraints have increased the interest in generating electric energy from renewable energy sources (RES) to provide a sustainable electricity supply. A main problem of those technologies (wind or solar power generation) is that they are not constant and reliable sources of power. This results inter alia in an increased demand of energy storage technologies. Related stake holders show a big interest in the technical, economic and ecologic aspects of new emerging energy storage systems. This comes especially true for electrochemical energy storage systems as different Li-Ion batteries, Sodium Sulfur or Redox Flow batteries which can be utilized in all grid voltage levels, a wide range of grid applications as well as end user groups (e.g. private households, industry). A prospective and active Constructive Technology Assessment (CTA) can help to minimize potential mismatches, wrong investments, possible social conflicts, and environmental impacts of new energy storage technologies in an early development stage. It is insufficient to exclusively look at the operation phase to assess a technology. Such an approach can lead to misleading interpretations and can furthermore disregard social or ecological impact factors over the whole life cycle. Different energy storage technologies have to be evaluated in a prospective manner with a full integrated sustainability and life cycle approach to form a base for decision making and to support technology developers in order to allow distinctions between more or less sustainable battery technology variations. Therefore CTA is used as a scientific approach using several “neighbouring” engineering orientated disciplines e.g. Life Cycle Analysis (LCA), Social Life Cycle Assessment (SLCA) or Life Cycle Costs (LCC) and their methodologies which were initially developed for other purposes. The aim of the presented PhD Thesis is to make an economic, technological and ecological comparison of Energy storage technologies based on a life cycle sustainability Analysis (LCSA), multi criteria Analysis (or evaluation) (MCA) and to develop a suitable LCSA-MCA model through a new combined highly interdisciplinary approach in frame of CTA. Dr.-Ing. Marcel Weil Prof. Dr. António Brandão Moniz