We have had a strong mechanism for interaction between power production companies and the power trading/supplier companies for a number of years by now. In the future we can expect new types of more interactive communications between single customers and groups of customers towards the energy market companies. We can also expect a stronger demand-side from the customers, e.g. to buy only green energy, only nu-clear etc. Power (kW) will be an important parameter aside of energy (kWh) and there will be new possibilities to buy energy when it is as cheap as possible. This may include new applications like charging batteries for your car when the electricity price is low. Differentiation of price may be not only as a direct function of time, but also energy availability like when it is windy, as wind power becomes a major part of many energy systems. Energy storage will be more important and perhaps we will get new possibilities to buy shares in central energy storages, in the same way as space is bought at servers for your applications, photos, web-pages etc. Other type of functions may develop as a result of the introduction of individual metering of first electricity and later on hot water and temperature. By metering the individual consumption and billing the exact amount that has been consumed, there will also increase the driving force also to perform energy and load saving actions, e.g. turning off high demand functions like “infra-heating”, “large screen TV” and similar, when other usages are on, and the price is high. We expect displays with interaction possibilities in all homes, where you can see your consumption and pricing information. These new type of systems will put new demands on both hardware for supply and software to handle the services/functions. As part of developing this, mathematical modelling of the systems and tests with simulators will be an important tool. Also new soft ware functions will be developed to support the actual services, like simulators giving information on how different actions you make as a user will influence your energy consumption in the future, both short term and more long term. For the more long term case, new investments in new hardware and software may be proposed and evaluated for users in both technical and economic terms. In this paper the system aspects including the costs is analysed through a simulation model. This includes the physical system as well as the user behaviour and possible effects of different price models, like a combination of kW and kWh. The effect on the users, the distributors and the power producers are evaluated.