Distribution ensures the flow of gas, coming from the high-pressure (HP) transmission network, in medium pressure (MP: between 20 and 4 bar) and low pressure (LP: below 4 bar) networks to consumption facilities (delivery points). These networks are also called interconnected networks, as opposed to other local distribution networks, which are fed by liquefied natural gas tanks (UAG) supplied by tanker trucks.

The distribution networks ensure the transit of gas between the national transmission network and the industrial and domestic consumption points (in MP and BP), under suitable conditions of quality of service.

The distribution system operators (DSO) operating under regional concession are listed below:

• Beiragás - Companhia de Gás das Beiras, S.A.
• Lisboagás GDL - Sociedade Distribuidora de Gás Natural de Lisboa, S.A.
• Lusitaniagás - Companhia de Gás do Centro, S.A.
• REN Portgás Distribuição, S.A.
• Setgás - Sociedade de Distribuição de Gás Natural, S.A.
• Tagusgás - Empresa de Gás do Vale do Tejo, S.A.

The DSO operating with local natural gas distribution licenses are listed below:

• Dianagás - Sociedade Distribuidora de Gás Natural de Évora, S.A.
• Duriensegás - Sociedade Distribuidora de Gás Natural do Douro, S.A.
• Medigás - Sociedade Distribuidora de Gás Natural do Algarve, S.A.
• Paxgás - Sociedade Distribuidora de Gás Natural de Beja, S.A.
• Sonorgás S.A.

The activity of DSO must be separated from the gas production or supply activities. DSO with more than 100 thousand customers (Lisboagás, Lusitaniagás, REN Portgás and Setgás) are legally unbundled, while the others only require functional and accounting unbundling between the distribution and supply of last resort activities.

Every two years, each DSO, in conjunction with the transmission network operator (TSO), draws up a 5-year investment plan: the Five-Year Development and Investment Plan for Distribution Networks (PDIRD-GN). This Plan is subject to public consultation and to an opinion from ERSE and the Directorate-General for Energy and Geology, and is approved by the Government, after being discussed in Parliament.

ERSE is responsible for the economic regulation of the gas distribution activity, setting the tariffs for the use of the distribution network and operators’ revenues. 

To find out more about this, have a look at the pedagogical guide Natural gas: how does it work?