The aim of the PhD project is to analyse the cost-effectiveness of energy efficiency programs that are implemented by energy companies at the end user's site. Electricity conservation and load shifting programs are evaluated with priority. This field of research is of particular interest as, in the year 2006, the European Union adopted the Directive on Energy End Use Efficiency and Energy Services, which encourages the Member States to reduce their national energy demand by 1 percent per year in the period from 2008 to 2017. The Directive considers energy companies as one of the main actors to reach this target. The analysis of benefits and costs is performed from the perspective of different market actors: the customer participating in an energy efficiency programme, the national economy, the society and various kinds of energy companies existing in the European liberalised energy market. The first step is to develop an appropriate methodology for the evaluation of energy efficiency programs that are implemented in the energy regulation context existing in Europe. Applying this methodology, costs and benefits of energy efficiency programs are calculated in a way allowing to compare the energy conservation costs with the costs of supply side technologies on the same level. The most common types of energy efficiency programs that are implemented in France and Germany are evaluated and compared with each other based on the developed methodology. Moreover, the impacts of existing current and potential future regulatory conditions existing in different European countries are assessed. The objective is to identify which regulatory changes are able to improve the framework conditions for the implementation of energy efficiency programs. Electricité de France (EDF) provides relevant data for the analysis. The Wuppertal Institute realises the research in co-operation with EDF Recherche & Développment.