GRIP CEE 2017 / Main Report

4.3.1.2 Summer period

In addition to the data for entry capacities used for the CEE GRIP Regional N-1 analysis during the winter period, the working gas volumes and maximum injection capacity to the underground storage facilities of each country are also used for the analysis during the summer period. The summer formula is set to determine how long a gas supply disruption through Ukraine and Belarus can last without endan- gering the ability to cover demand and/or to fill the storage facilities in the respective country. After a matching/correction of entry and exit capacities of each intercon- nection point (lesser-of rule), the surplus gas is allocated to neighbouring countries to meet their domestic demand. The N-1 value for the summer is calculated for each country by setting the interconnection points of the main supply corridor to zero or to the minimum volume that an upstream country (next or nearer to Ukraine/Bela- rus transport to a relevant interconnection point) is able to export. If the investigat- ed country has surplus gas for sharing after satisfying its demand, the gas is then allocated to downstream countries, where necessary. These values are used for the N-1 calculation as entries for each particular country.

Summer N-1 Formula:

For calculation purposes, the time period for injection into underground storage facilities during the summer is considered to be 180 days in duration. EP_IN All border entry points (transmission and LNG) capable of supplying gas to the calculated area (GWh/d) P National production, entry capacity (GWh/d) D_AS Domestic average summer demand (1 in 20) (GWh/d) XP_OUT Remaining gas to fulfil demand in neighbouring countries and for injection into underground storage facilities in country concerned (GWh/d) S_WGV Working gas volume of underground storage facilities in country concerned (GWh) S_X Storage, exit capacity (injection) (GWh/d)

Image courtesy of Plinovodi

Central Eastern Europe GRIP 2017 |

53