What is AS4?
AS4 (Applicability Statement 4) is a protocol for standardised message exchange between gas transmission system operators (TSOs) and their counterparties, in Europe. It is used in balancing and congestion management. Compared to AS2 (Applicability Statement 2) which has been in use for these messages before AS4 is based on web services. As a data exchange format, Edig@s-XML is used for announcing the communication processes:
- NOMINT (balancing)
- NOMRES (balancing) and
- CHACAP (capacity management)
Where is AS4 used?
Based on the EU Regulation 2015/703 of 30 April 2015 to establish a network code on interoperability and data exchange rules the message formats AS4 and Edig@s-XML are mandatory within gas trading for the communication processes to announce.
- The re-nomination limit for congestion management (CHACAP)
- The nomination, re-nomination and confirmation of the same for balancing management. (NOMINT, NOMRES)
In many European countries e.g. Sweden, Germany, Denmark and Italy this is mandatory from end of 2017 or from the start of 2018.
Those directly affected are therefore all market partners that nominate, get matched or obtain capacity stock reports at the respective transmission network operator’s cross-border and market-area transmission points
In light of this, ENTSOG (European Network of Transmission System Operators) has defined a specific sub-set which outlines communicating via AS4 in detail and standardises the connection to different market partners (AS4 Usage Profile).
Advantage of AS4
AS4 is a secure data protocol which is based on web services. The authorship is guaranteed by digital signatures and data security by encryption. The sender receives a digital receipt, which can be used to prove on-time delivery.
In comparison to AS2 not only the exchange of data via “Push” is possible with AS4, but also “Pull” exchanges. The receiver can actively retrieve messages as the AS4 server is permanently responsive. The HTTP connection is established in the communication event and data can be received at any time by linked systems. Data is exchanged independent of business times and server availability.
AS4 and Compello
Compello provides European utility companies with effective support: In terms of data exchange via AS4, Compello offers customers the choice between a stand-alone solution, an upgrade module for the marketing communication platform Compello Connect and an OEM version.
All options have been initially designed to focus on the requirements of gas transmission network operators, however, they can be upgraded at any time for the electricity sector or extended beyond the ENTSOG standard.
The Compello AS4 Gateway (stand-alone solution) can be installed parallel to existing marketing communication applications. It is usually up and running within a day.
Related terms to AS4: AS2, ENTSOG, Edig@s-XML, CHACAP, NOMRES, NOMINT, Network code on interoperability and data exchange rules, Webservice, Data exchange