The study examines different variations of market openings. Besides a fully opened market, it also analyses variations with a gradual opening over a period of time or with a differentiation of the opening in regard to customer attributes e.g. the exclusion of market access for households. Furthermore, the issue is being discussed, whether a basic gas supply is necessary at all. The study also evaluates the impacts of a market opening in relation to the economy, the society and the environment. The analyses carried out show that with a continuation of the opening of the gas market, there are positive effects on the economy and the private households to be expected. Moreover, the greatest potentials for efficiency gains can be achieved by a complete opening of the market.