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RWE GSNGeneral Guide for Ordinary Shipper Created by:Jaromír Šivic,Luboš Zelinka Cygni Software 15.4.2013
Introduction This document covers general behavior for ordinary shipper in RWE Gas Storage Nomination System (GSN). It briefly describes physical structure of RWE underground gas storage facilities, focuses on nomination, matching process, correct timing, gas flow between underground gas storage and transmission system operator and final allocations. It also contains RWE GSN Web portal guide for new shipper.
Physical Structure For better understanding of system behavior it is necessary to briefly describe physical structure and business structure of RWE underground gas storage facilities. Each underground gas storage facility have specific physical location and a set of transmission system operators connected to it, but the structure and business logic is the same for all RWE underground gas storages.
Physical Structure Underground gas storage (UGS) is identified by its capacity, location and unique name. Capacity of Underground gas storage is always set in Nm3 (normal cubic meters). Each underground gas storage facility is connected to at least one transmission system operator, that way gas can be transferred, stored and later withdrawn. Exchange of gas between transmission system operator and underground gas storage is done via grid connection point.
Physical Structure Grid connection point (GCP) is a place where gas is exchanged between transmission system operator and underground gas storage. Each grid connection point is always connected to exactly one underground gas storage facility and exactly one transmission system operator. You may imagine GCP as a compressor injecting gas into the underground gas storage and later withdrawing it back into the transmission system operator’s pipes.Note that each underground gas storage facility may have multiple grid connection points.
Business Structure Business structure closely follows physical structure of RWE UGS facilities. Each shipper has its own portfolio of contracted underground gas storages where the shipper can store gas. Under each underground gas storage there must be at least one contracted grid connection points. Each grid connection point must contain at least one balance grid.
Business Structure Balance grid is a business entity used to distinguish type of transferred gas (Natural Gas, Biogas, …)Unique pair of shipper codes is assigned to each balance grid. Shipper codes are used during nomination and matching process and identifies every transfer of gas between underground gas storage and transmission system operator.
Business Structure – Web Portal User may have an access to send nominations and browse values for many different shippers. List of available shippers is displayed as soon as user logs in.
Business Structure – Web Portal If user has an access to send nominations and browse values only for one specific shipper then he will be redirected to the main page of the shipper.
Business Structure – Web Portal Business hierarchy of contracted underground gas storages and grid connection points is used very often on the web portal.
Business Structure – Web Portal List of balance grids can be displayed when browsing Nominations & Allocations
Nomination and Matching Process Nomination and matching process is always initiated by shipper. RWE GSN supports several ways how shipper can send nomination to the system. • Using Edigas Messages. (Recommended) • Via Web Portal. • Official request to commercial dispatching (via email: gs.dispatching@rwe.com, via phone: +420 267 974 570).
Nomination – Edigas Messages Edigas messages – the most commonly used way to exchange nominations between shipper and RWE GSN. Nomination scenario closely follows EASEE-gas Common Business Practices Implementation and it gives shipper the possibility to change nominated values (very quickly) with standard feedback containing information about acceptation and matching process results. NOMINT messages (XML format) are used to initiate nomination process. NOMRES messages (XML format) are used to confirm accepted values and matched values.
Nomination – Edigas Messages Exchange of messages (NOMINT, NOMRES, …) is handled by RWE GSN Enterprise Service Bus. Supported protocols: • FTP/ISDN • FTPS/Internet • SMTP (we discourage shipper to use this way) Note messages are not processed immediately after they are received. It takes 30 seconds until they are validated, decomposed and pushed to the MSGStore for further analysis. It takes another 30 seconds until hourly values are stored in proper time series. Therefore shipper will see the nomination on the web portal after 1 minute.
Acceptation Procedure - Timing Acceptation procedure window for nominations or re-nominations on GD+1 (next gas day) starts at: • 14:00 CET/CEST • 16:00 CET/CEST • 20:00 CET/CEST • 24:00 CET/CEST • 01:00, 02:00, 03:00, 04:00, 05:00 CET/CEST
Acceptation Procedure - Timing Acceptation procedure window for nominations or re-nominations on GD (ongoing gas day) starts every hour at: 06:00, 07:00, …, 03:00 CET/CEST Regarding re-nominations: gas flow direction cannot be changed immediately. There must be at least 2 hours reserve for technical dispatching to change direction of gas flow.
Acceptation Procedure - States • Received – Initial state of nomination - indicates that nomination message (NOMINT), was received by RWE GSN enterprise service bus, but it was not processed yet. • Waiting – Nomination was decomposed into the hourly values, stored into proper time series and awaits for next acceptation procedure window. • Processed – Nomination is being processed, but decision was not made yet. Under the normal circumstances nomination is processed in a matter of minutes and then it is switched to accepted state. When “acceptation procedure checks” are not passed correctly system has to wait for decision of operator (human) – that may take 2 hours. If operator does not react in 2 hours then nominated values are reduced and nomination is accepted.
Acceptation Procedure - States • Accepted – Indicates that nomination was accepted. Shipper should always take a look on accepted values, because they may be different from originally nominated values. • Overchanged – It may happen that shipper wants to change nominated values and sends new nomination before the most recent one was even processed. In that case the latest unprocessed nomination is marked as changed (state “overchanged”) and the new one is marked as Received. • Out of time (out of order) – If shipper attempts to nominate values to the past or change already accepted values in the past then the nomination is immediately marked as “out of time”. • Error – Internal error or business logic error. User is able to see the state of nomination on “Nomination History” page.
Acceptation Procedure – Contracts Contracts in RWE GSN are linked to grid connection points and underground gas storages, but there are no contracts for balance grids. Contract contains information as max. injection capacity, max. withdrawal capacity, max. level of working gas, start date, end date. All nominations during acceptation procedure are tested using following conditions. • Sum of nominations on all balance grids under the specific grid connection point must not exceed contracted capacities for that grid connection point. • Sum of all nominations on all balance grids under the specific underground gas storage must not exceed contracted capacities on that underground gas storage. Note that injection/withdrawal capacities are influenced by injection/Withdrawal curves.
Acceptation Procedure – Contracts Contracts are placed in the “contracts” folder.
Acceptation Procedure – Contracts Nomination must not exceed maximal aggregated capacities on UGS or GCP level. Note that UGS contracts contains injection/withdrawal curves which may influence maximal aggregated injection/withdrawal capacities of connected GCPs and maximal technical injection/withdrawal capacities of connected GCPs.
Injection CurvesWithdrawal Curves Injection/withdrawal f(x) is piecewise-constant function. The only argument of this function is level of gas stored in underground gas storage (also known as CBA%). Result of the function is taken as a multiplier for aggregated injection/withdrawal capacities.
Injection/Withdrawal Curves Example Injection Curve of Shipper A is defined as a piecewise-constant function f(x) described on a slide before. Let the “Shipper A” CBA% be 50%. Let the Shipper A – Aggregated Maximal Injection Capacity be 100 000 Nm3. Then the final maximal injection capacity is: = => => 80% => 0.8 => 80 000
Acceptation Procedure – Technical Capacities Under the standard circumstances are technical availabilities always equal or higher than aggregated contractual capacities. If there is some technical issue on grid connection point or underground gas storage then technical availabilities might be lower than aggregated contractual capacities – and in that case nomination should not exceed technically available capacities (multiplied by result injection, withdrawal curve function).
Nominations via Web Portal It is possible to send nominations as well via web portal. In that case shipper is obliged to contact TSO and send nomination to him as well. Operator uses nominations via web portal as a backup solution.
Matching Procedure Matching procedure is always initiated by TSO. It should not take longer than one hour to match accepted values. Result of matching procedure(for every single hour) is always the value representing less amount of transferred gas. Final nomination result (NOMRES status 16G) is sent to the shipper as soon as matching procedure is finished.
Matching Procedure - States • DelordReceived – Initial state of matching - indicates that matching message (DELORD), was received by RWE GSN enterprise service bus, but it was not processed yet. • SendDelres – Indicate that matching was processed, values were matched and response should be sent back to TSO. • DelresSent – Indicates that matching response (DELRES) was sent back to the TSO. • Out of time (out of order) – If TSO attempts to match values to the past or change already matched values in the past then the matching is immediately marked as “out of time”. • Error – Internal error or business logic error.
Communication with Technical Dispatching • Technical dispatching sends to RWE GSN (using real-time protocol TASE.2) information about technical availabilities/un-availabilities for each physical GCP. RWE GSN takes that value into account during acceptation procedure. • As soon as acceptation and matching procedure is finished – RWE GSN sends to technical dispatching “Gas Flow Schedule” messages (for each physical GCP) and awaits for the confirmation. • RWE GSN shares with technical dispatching (in real-time via TASE.2) the most recent OBA values for each physical GCP.
Nominations & Allocations - Strategies • Manual allocations. Commercial dispatcher has to write allocated values for each BGR of the shipper on a daily basis. • Allocated as nominated (and matched). Shipper always gets the amount of gas matched by transmission system operator. Differences are balanced using special shipper SSO and sent to technical dispatching using real time protocol TASE.2. • Allocated as measured – allocations are equal to amount of gas injected or withdrawn from UGS
Nominations & Allocations - Strategies 4. Allocated to balance account. Currently there is only one shipper following this strategy in the system called SSO. SSO is a special shipper used by technical dispatching to eliminate differences between sum of matched values (per GCP) and transferred amount of gas. 5. Proportional balancing – used in past by RWE S&T Netherlands. Aditional manual allocations, corrections and transferes of gas can be used with any strategy mentioned before. Strategies can be changed in time (RWE S&T Netherlands)
Custom Excel Reports Every user has a right to create custom excel reports. Custom excel reports are usually used to export large amount of data from RWE GSN and later import them into the shipper’s information system for further analysis.
Special Shippers • Shipper RWE S&T NL • Nominations are received processed and matched at any time. • In the past there was proportional balancing • Archived/locked GCPs • Shipper SSO • No nomination • No matching • Used only for technical dispatching as a balancing shipper • Shipper Eigengas • Nominations are automatically matched without cooperation with TSO • Used for gas transfers between BGRs and special BGR called blow out gas
Old Version of Web Portal Old version of web portal is used by SSO, commercial dispatchers. In some cases it might be used by shippers. The navigation is not so straight forward, layout conception is different, but some users are accustomed to it. It will take some time before we terminate support (if we ever terminate support) for it.
