In this paper we develop a new market design for the German electricity market. Our new market design simultaneously ensures security of energy supply and ongoing expansion of renewable energy (RE). The methodological approach applied considers the special challenges resulting from the intermittent nature of RE we simulate developments in the German electricity market between 2015 and 2034 and differentiate across various power plant technologies according to their ability to flexibly react to changes in the residual load. In theory, a composition of power plants that is optimally adapted to residual load always leads to the most cost efficient supply of electricity. However, our empirical analysis demonstrates that this does not necessarily lead to an improved market environment, both in terms of power plant profitability as well as uninterrupted power supply.