The ‘Europe 2020 strategy includes the reduction of greenhouse gas emissions by 20 percent, the increase of renewable energies up to 20 percent and the increase of energy efficiency by 20 percent by 2020. The federal energy efficiency law (EEffG) in Austria obliges energy suppliers to do annual measures for a more efficient use of energy by 2020. The starting point for this thesis is a dilemma within the EEffG: the supplier commitment, the setting of energy efficiency measures and the related energy saving is offset by the core business, the sale of energy and energy products. The thesis has two objectives: first to analyze the long-term effects of the EEffG on energy suppliers, and second the summary and analysis of proposals in terms of the future of energy supply companies. Proposals, such as the development of new business models, energy services and the increased binding of customers are analyzed with a three-stage Delphi study. The thesis discusses the development of the energy supply and the impact on the core business of energy suppliers, as well as the role and importance of affected actors. A SWOT analysis provides a comparison of internal strengths and weaknesses, and external opportunities and threats in dealing with the effects of EEffG on energy suppliers. The study shows that the federal energy efficiency law strengthens the relationship between energy suppliers and companies. New service offers in the sector of “building” and “transport”, electro-mobility and charging infrastructure, as well as “contracting” are the essential solution proposals. Due to the shift towards decentralized forms of energy production, energy suppliers are required to include alternative energies in their overall portfolio.