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SNGN Description
System Balancing
Balancing Rules
Balancing Actions
Forecasting Party
Available Capacities
Capacity Allocation
Oversubscription & Buyback
Gas Characteristics
Natural Gas
Sulphur Compounds

System Balancing

The National Natural Gas System (SNGN) holds a Balancing Zone, the National Natural Gas Transportation Network (RNTGN), comprising four entrances, namely 2 international interconnections per pipeline, one entrance from the Sines LNG Terminal (TGNL ) and a connection to the Underground Storage in Carriço (AS), and multiple outputs, such as all outputs for consumption, distribution networks, as well as both international interconnections and connection to AS.

To operate in the SNGN, shippers must establish and maintain quantitative stocks of natural gas (NG) in the infrastructures that make up the National Transport Network, Storage Infrastructure and LNG Terminal (RNTIAT): RNTGN, TGNL and AS. The minimum levels of these NG stocks, are set up to meet security of supply obligations and to ensure the proper functioning of the infrastructures in compliance with the legislation and in accordance with SNGN Global Technical Management Procedures Manual (MPGTG) . Shippers can use the capacity of RNTIAT through processes of programming and nomination of gas quantities, under the rules defined in the MPGTG. For the use of the capacity is required the prior acquisition of Capacity Utilization Rights (DUC), which can be carried out over different time horizons of capacity allocation processes that are implemented in accordance with the Natural Gas Sector Infrastructure Access Procedures Manual (MPAI)

Within its competences of managing and coordinating the operation of the infrastructures of RNTIAT, it is the obligation of the operator of the RNTGN, in its Global Technical Management activity of the SNGN (GTG), to exchange NG between the infrastructures, ensuring the safety of persons and infrastructures and the security of supply. Furthermore, economic and efficiency factors should be taken into account and the costs should be allocated to the responsible parties, infrastructure operators or shippers.

For each gas day, GTG establishes the NG flows necessary for the safe and efficient management of RNTIAT, using, if necessary, balancing actions, with the objective of:

  • Maintain the transmission network within its operational limits;
  • Achieve an end of day linepack position in the transmission network different from the one anticipated on the basis of expected inputs and off-takes for that gas day, consistent with economic and efficient operation of the transmission network.

When deciding upon the appropriate balancing actions, GTG shall consider the following merit order:

  1. Purchase and sale of standard short-term products on a trading platform, under the following circumstances:
    • Prioritising the use of title products;
    • Using locational products when the use of title products could not ensure the operation of the transmission netwotk within its operational limits;

  2. Balancing services under the following circumstances:
    • If short term standardised products will not or are not likely to provide, upon assessment of the transmission system operator concerned, the response necessary to keep the transmission network within its operational limits;
    • Lack of liquidity in the short term standardized products trading;
    • When the use of balancing services are more economic and efficient.

  3. Linepack when, upon assessment of the transmission system operator concerned, short term standardised products and balancing services will not or are not likely to provide the response necessary to keep the transmission network within its operational limits;

In order to minimize GTG compensation actions, it is the responsibility of the shippers to maintain the balance of their portfolios, in accordance with the rules established in MPGTG.