There must always be a balance between the supply and consumption of electrical power. In the balancing power market, the participants bid a price to alter production or consumption. This is used when any imbalances arise in the power system.
When there is a balance between the supply and the consumption of electrical power, the frequency of the voltage in the Nordic power system is 50.00 Hz.
Power cannot be stored. It must be generated at the same time it is used. This physical fact means that the free power market has certain challenges and schemes that differentiate it from the sale of goods that we can see and touch.