This project provides findings about the way customers handle variable tariffs. 24 ELE customers were equipped with intelligent measuring instruments. Due to the great price range from  10 ct/kWh to 40 ct/kWh at different tariff times there is a great saving potential available for the customers. Via an Internet portal or an SMS to a mobile phone the participants get to know the tariff forecast for the following day, which is closely oriented to the availability  of regenerative energies, and can, with the help of this information, adjust their power consumption in such a way that they make use of favourable tariff times for energy-intensive activities and hence save electricity costs. For the electricity customer a time-variable tariff system thus results that can be made use of in order to save energy costs. If sufficient customers adjust their electricity demand in accordance with the tariff times for the grid operator a better load distribution in the grid results. In the current simulation in which the customer's existing electricity contract does not have to be amended a max. rebate of 100 euros can be earned that is paid out at the end of the year.