Article 13 5.

If there is more than one Member State that could provide solidarity to a requesting Member State, the requesting Member State shall, after consulting all Member States required to provide solidarity, seek the most advantageous offer on the basis of costs, speed of delivery, reliability and diversification of gas supplies. Where the available market-based offers prove not to be sufficient to cover the deficit in gas supply to the solidarity protected customers in the requesting Member State or, where the requesting Member State has taken temporary measures to reduce the non-essential gas consumption of protected customers in accordance with Article 11(7a), the deficit in gas supply of the essential volumes of gas consumption to its solidarity protected customers, the Member States required to provide solidarity shall be obliged to activate non-market-based measures.