The pursuit of a new, sustainable power generation has led to a soaring employment of intermittent renewable energy sources (RES), such as wind and solar power. Traditional, load-following power systems face ever increasing problems with this intermittent supply. Demand Side Management (DSM) and Vehicle-to-Grid (V2G) could help relieving the power system, offering much greater flexibility in energy management. In order to evaluate the potential of DSM and V2G in urban areas, a model has been set up for Bern, a medium sized city in Switzerland, which was used to simulate the central control of white goods, electric heatings and electric vehicles. The aim was to balance all generation-consumption mismatches and to find the cost saving potential of DSM. This was done by both a central on&off-control of each device and an optimization of its use. The analysis showed that on average about 33% of all generation-consumption mismatches can be compensated just by DSM. Together with V2G it is up to 60%. The savings potential is about 3.3% of the electricity purchase costs. This is more than enough to support RES in Bern to a high fraction of the power mix and make DSM and V2G a valuable alternative for integrating RES into the existing power system.