Article 7 4.

using the standards specified in Articles 5 and 6. The risk assessment shall describe the calculation of the N – 1 formula at national level and where appropriate include a calculation of the N – 1 formula at regional level. The risk assessment shall also include the assumptions used, including where applicable those for the calculation of the N – 1 formula at regional level, and the data necessary for such calculation. The calculation of the N – 1 formula at national level shall be accompanied by a simulation of disruption of the single largest gas infrastructure using hydraulic modelling for the national territory as well as by a calculation of the N – 1 formula considering the level of gas in storages at 30 % and 100 % of the maximum working volume;

taking into account all relevant national and transnational circumstances, in particular market size, network configuration, actual flows, including outflows from the Member States concerned, the possibility of physical gas flows in both directions including the potential need for consequent reinforcement of the transmission system, the presence of production and storage and the role of gas in the energy mixes, in particular with respect to district heating and electricity generation and for the operation of industries, and safety and gas quality considerations;

running various scenarios of exceptionally high demand for gas and disruption of gas supply, taking into account the history, probability, season, frequency and duration of their occurrence and assessing their likely consequences, such as:

identifying the interaction and correlation of risks among the Member States in the risk group and with other Member States or other risk groups, as appropriate, including, as regards interconnections, cross-border supplies, cross-border access to storage facilities and bi-directional capacity;

taking into account risks relating to the control of infrastructure relevant to the security of gas supply to the extent that they may involve, inter alia, risks of underinvestment, undermining diversification, misuse of existing infrastructure, including hoarding of storage capacities, or an infringement of Union law;

taking into account the maximal interconnection capacity of each border entry and exit point and various filling levels for storage;

taking into account scenarios of a prolongeddisruption of a single supply source.