3.1.2. m) Methodology for calculating technical capacities of the gas transmission system

“On relation to their own systems and services, the transmission system operators are required to disclose at last the following information:

m) each of the transmission system operators are obliged to disclose a detailed, comprehensive description of the methodology and procedure used for the calculation of the technical capacity, including information with respect to the applied parameters and key assumptions.”

As per Section 6.13.3 of BCC

**Determination of the capacity on the natural gas transmission system**

(a) For the natural gas transmission system, the capacities can be determined:

i. maximum daily capacity (MJ/day);

ii. maximum hourly capacity (MJ/hour);

iii. maximum daily available capacity (MJ/day);

iv. maximum hourly available capacity (MJ/hour);

(b) Such capacities shall be determined for every entry and exit point.

(c) The natural gas supplier shall establish the feasibility of the ordered natural gas transmission tasks with reliance on mathematical modeling, hydraulic simulation (hydraulic testing)

(d) The m3/hour, m3/day capacity values for any specific network point shall be converted to the MJ/hour, MJ/day value with the use of the calorific value published for the given point in QSS (Quality-Based Settlement System).

Methodology for the determination of the booked and available capacities

**Methodology for the determination of booked capacities**

During the determination of booked capacities, the total capacity specified in the currently effective capacity booking and natural gas supply contracts and booked by any system user at the entry and exit points shall be taken into consideration, in the following breakdown:

i. Firm capacities (any capacity booked for over one year, booked for one year, book seasonal, booked on a seasonal, monthly, daily basis);

ii. Interruptible capacity (capacities booked for one year, month, day in total);

iii. Capacities in reverse direction to the direction of physical flow (backhaul capacities).

**Methodology for the determination of available capacities**

(a) The boundary conditions of the determination of available capacities in the natural gas transmission system are:

i. Calculated from the geometric and hydraulic properties, the maximum flow during a unit time shall be determined for the individual entry and exit points with the use of hydraulic calculations.

ii. In relation to the hydraulic properties, the maximum capacity and pressure data of the connected systems (underground gas storage facilities, import entry points, entry points of domestic production) shall be determined for the period under review.

iii. Available capacities shall be determined in MJ/hour units, the daily maximum capacity is a 24-fold value.

iv. For the determination of available capacities, returned capacities shall also be taken into account.

(b) The available capacities at the network points shall be specified for 10 years in advance in the following breakdown:

i. In a daily breakdown for the current month.

ii. In a monthly breakdown for 18 months in advance.

iii. In an annual breakdown for the additional years.

(c) The methodology for the determination of available capacities at the network points of the natural gas transmission system is applicable to the following cases:

i. Firm available capacities of the network points.

ii. Interruptible available capacities of the network points.

iii. Available backhaul capacity.

**Firm available capacities of the network points**

Firm available capacities of the entry points

(a) The firm available capacities of the entry points shall be determined as follows:

i. Data and boundary conditions considered:

- Maximum daily (MJ/day) and hourly (MJ/hour) capacity data for the entry points (import, underground gas storage facility, domestic production) of the high performance gas transmission system.
- Data for daily capacities (MJ/day) booked by system users.
- In the case of the capacity demands placed by system users, the number of hours for 24-hourly peak utilization has to be specified for the conversion between hourly and daily capacities.
- Available capacities shall be determined as the difference between the maximum daily capacities at the entry points of the high performance natural gas transmission system and the total volume of firm daily capacities booked by the system users for the given entry point.

ii. Available capacity = (maximum capacity of the given entry point) – (total volume of firm capacities booked for the given entry point). For the determination of the available capacity, the capacities booked by the natural gas supplier, the natural gas distributor and natural gas storage facility operator for technological and loss management purposes in relation to their own systems at the entry points of the natural gas transmission system – and capacities booked for the maintenance of the equilibrium of the system – shall be deducted from the largest hydraulically transmissible volume.

For the replenishment of the volumes of the use of natural gas for technological purposes and losses, the capacity bookings of natural gas distributors and natural gas storage facility operators shall be determined with respect to the planned use of natural gas for technological purposes in their systems and the demands of system users in their systems, in view of the operating experience earned in the previous 3 gas years.

The natural gas supplier shall meter the use of own gas in the natural gas transmission system, as well as the natural gas distributed at the entry and exit points on a daily basis. The volume of natural gas utilized by the natural gas supplier for the replenishment of the volumes of the use of natural gas for technological purposes and losses shall be determined with the following formula:

Technological demand = metering difference and loss + use of own gas.

Where the metering difference

**=**

(closing volume + transferred volume /meter readings at exit points/)

**–**

(opening volume + received volumes /meter readings at entry points/)

With reliance on the above procedure, the natural gas supplier shall determine the volume of the utilization of natural gas for technological purposes. The largest daily volume of natural gas utilization for the previous 3 gas years corresponds to the capacity demand of the natural gas supplier at the entry point.

iii. Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

**Firm available capacities of the exit points**

(a) The available capacities of the exit points shall be determined as follows:

i. Data and boundary conditions considered:

- maximum daily (MJ/day) and hourly (MJ/hour) capacity data for the exit points.
- data for daily capacities (MJ/day) and hourly (MJ/hour) capacities booked by system users at the exit points.

ii. Theoretical available capacities at the exit points shall be determined as the difference between the maximum daily/hourly capacities at the entry points and the total volume of daily capacities booked by the system users for the given exit point:

- Theoretical available capacity = (maximum capacity of the given exit point) – (total volume of firm capacities booked for the given exit point).

iii. Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

**Interruptible available capacities of the network points.**

Available interruptible capacity at the entry points

(a) The interruptible available capacities of the entry points shall be determined as follows:

i. Data and boundary conditions considered:

- Maximum (MJ/hour) capacity data for the entry points (import, underground gas storage facility, domestic production) of the high performance gas transmission system.
- Data for firm daily capacities (MJ/day) and hourly (MJ/hour) capacities booked by system users.
- In the case of the capacity demands placed by system users, the number of hours for 24-hourly peak utilization has to be specified for the conversion between hourly and daily capacities.
- Interruptible available capacities shall be determined at the entry points where firm capacities are fully booked, or the natural gas supplier has offered interruptible capacities due to the prevailing conditions of supply.
- Available capacities shall be determined as the difference between the maximum hourly capacities at the entry points of the high performance natural gas transmission system and the total volume of maximum hourly interruptible capacities booked by the system users for the given entry point, to which the absolute value of booked backhaul capacities shall be added:
- Available capacity = maximum capacity of the given entry point – total volume of interruptible capacities booked for the given entry point + absolute value of the booked backhaul capacities.
- Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

Available interruptible capacity at the exit points

(a) The interruptible available capacities of the exit points shall be determined as follows:

i. Data and boundary conditions considered:

- Maximum (MJ/hour) capacity data of the high performance natural gas transmission system.
- Data for firm daily capacities (MJ/day) and hourly (MJ/hour) capacities booked by system users.
- In the case of the capacity demands placed by system users, the number of hours for 24-hourly peak utilization has to be specified for the conversion between hourly and daily capacities.
- Interruptible available capacities shall be determined at the exit points where firm capacities are fully booked, or the natural gas supplier has offered interruptible capacities due to the prevailing conditions of supply.
- Available capacities shall be determined as the difference between the maximum hourly capacities at the exit points of the high performance natural gas transmission system and the total volume of hourly interruptible capacities booked by the system users for the given entry point, to which the absolute value of booked backhaul capacities shall be added:
- Available capacity = maximum capacity of the given exit point – total volume of interruptible capacities booked for the given exit point + absolute value of the booked backhaul capacities.

ii. Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

Available backhaul capacities of the network points

**Available backhaul capacities of the entry points**

(a) The available backhaul capacities of the entry points shall be determined as follows:

i. Data and boundary conditions considered:

- Maximum (MJ/hour) capacity data for the entry points (import, underground gas storage facility, domestic production) of the high performance gas transmission system.
- Data for interruptible daily capacities (MJ/day) and hourly (MJ/hour) capacities booked by system users.
- At the import entry points, the minimum delivery volumes required for the secure supply of the national natural gas system shall be taken into consideration.
- Determination of the available backhaul capacity: the minimum hourly volume required for the secure supply of the national natural gas system and the hourly backhaul capacities booked for the given entry point shall be deducted from the hourly capacities booked for the entry points of the high performance natural gas transmission system.
- Available capacity = firm capacity booked for the given entry point – minimum hourly volume required for the secure supply of the national natural gas system – total volume of backhaul capacities booked for the given entry point.

ii. Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

Available backhaul capacity at the exit points

(a) The interruptible available capacities of the exit points shall be determined as follows:

i. Data and boundary conditions considered:

- Maximum (MJ/hour) capacity data of the high performance natural gas transmission system.
- Data for interruptible daily capacities (MJ/day) and hourly (MJ/hour) capacities booked by system users.
- Available backhaul capacities shall be determined as the difference between the total volume of firm hourly capacities booked at the exit points of the high performance natural gas transmission system and the total volume of hourly backhaul capacities booked by the system users for the given entry point:
- Available capacity = (firm capacity booked for the given exit point) – (total volume of backhaul capacities booked for the given exit point).

ii. Nevertheless, the utilizability of the calculated theoretical available capacity depending on the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.

(b) The feasibility of natural gas transmission tasks shall be tested as follows:

i. The feasibility of any natural gas transmission task shall be tested with respect to the given boundary conditions, as per the provisions of Section 6.13.1 of BCC.

ii. The feasibility of any natural gas transmission task depends on the following:

- available capacity published for the entry point and theoretical available capacity published for the exit point;
- hydraulic parameters of the natural gas transmission system;
- the hydraulic conditions of the natural gas transmission system, i.e. the source and destination, as well as the boundary conditions of transmission.
- The natural gas supplier shall perform all feasibility calculations with respect to all the already booked capacities.

Available capacity at the Hungarian Gas Balancing Point (HGBP)

The capacity of HGBP as a virtual point is available without limitations.