According to the operating principles of the gas market each market participant must ensure that the quantity of gas given into or purchased from the grid in each trading period is equal to the quantity of gas taken from or sold into the grid.
In practice, market participants are not able to do this for every gas day. Therefore, each one must have a contract with a supplier to ensure that shortfalls of gas are covered and excess gas is purchased. This system is called open supply. The open supplier, who has an open supply contract with the Transmission System Operator, is called a balance provider.
Elering as the transmission system operator (TSO) is responsible for the Estonian gas system’s balance and the balance settlement with the Balance Responsible Parties. The open supply contract between the balance provider and the TSO is called a balance agreement. The standard terms and conditions (unofficial translation) of this agreement are publicly disclosed and are the same for all balance providers. The balance agreement consists of the rules for balance service and the conditions for the purchase and sale of imbalance energy.
Balance management is regulated in the natural gas act § 11 – § 17.
- Open supply chains of the Balance Responsible Parties
In order to ease the daily data exchange and management of the balancing portfolios all the entities of the gas marker are coded according to EIC schema. The coding schema has been developed by the European Network of Transmission System Operators for Electricity and it is in Europe-wide use.
According to the natural gas act § 22 (13) the distribution system operator (DSO) is obliged to submit the metering data necessary for balance settlement to the TSO and Balance Responsible Parties. Each DSO has been assigned an EIC code range for all of its metering points.