This paper analyzes the interaction of renewable energy sources, CO₂-price and investments in storages. With an electricity market model the German energy system is observed. Therefore three assumed renewable shares, a CO₂-price-range and three storage types (namely hourly, daily and seasonal) are included in the analysis. The aim is to assess which type of storage has the highest value under uncertain but crucial frame conditions. It can be shown that an increasing renewable energy share results in a higher marginal values for storage in general. CO₂-prices strengthen this effect. Additionally they have a high impact on the conventional power plant mix as well as on the investment in the different storage types.