In practice, market participants are unable to ensure a balance between consumption and production every hour. For this reason, each market participant must have a contract with one supplier (electricity supplier) that ensures the sale of missing electricity and the purchase of excess energy, i.e. the so-called opened supply. This open supplier, who in turn has an open supply contract with the system operator, is called a balance provider. 

Open suppliers

An open supply contract between a balance provider and a system operator is called a balance agreement, the standard terms and conditions of which are public and the same for all balance providers.

More information about the balance agreement can be found here Balance agreement | Elering.

The system operator uses capacity reserves to compensate for deviations within the balance period caused by generation, network disruptions and changes in consumption. To this end, the system operator enters into emergency reserve and balancing agreements with the system operators of power plants and neighbouring systems that provide the corresponding service.