For each local area, there is a local grid operator who handles the local low-voltage system (cf. the municipal and county service of the roads). While the high-voltage system is operated by the system operator, the local low-voltage system is handled by non-commercial monopoly participants.

The system operator is also responsible for keeping the power system in his area balanced. Consequently, the system operator has the superior, physical ruling and control of the power system in his area. The physical control and maintenance of the power system is done in the same way in the market ruled system and the planned economy system. This originates in the simple fact that the natural laws of electricity are the same whether we have planned economy or market economy.

The commercial participants are not, and cannot be, responsible for the security of supply. If a South Swedish retailer, for example, has bought power from a North Swedish producer, the North Swedish producer cannot guarantee that there will be power in the plug at the retailer’s customers. What the commercial participants deliver to each other and the end users are exclusively the prices (along with the bills belonging to them). Since the commercial participants deliver financial services only, their role depends on how liberalised the market is.