Gemini System

Learn about this suite of online applications which are used for managing the transport of gas through the transmission network.

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    What is the Gemini System?

    The Gemini System is a suite of online applications for managing the transportation of gas through the National Transmission System (NTS) in Great Britain.

    These online applications are used for:

    • Capacity Management (Entry and Exit Capacity)
    • Capacity Trading
    • Commercial Balancing
    • Invoicing (Capacity and Energy Balancing)


    Gemini Entry and Gemini Exit

    The Gemini System is made up of Gemini Entry and Gemini Exit.

    Gemini Entry is used for:

    • all Entry Capacity related activities to ensure you have booked the right amount of space to bring gas onto the NTS
    • all Energy Balancing activities which is the amount of gas you intend to flow in and out of the NTS

    Gemini Exit is used for:

    • all Exit Capacity related activities to ensure you have the right amount of space booked to bring gas off the NTS through one of the exit locations including the distribution network (DN) offtakes

    The Gemini System is owned by National Gas Transmission and Xoserve is responsible for managing and operating the system on their behalf.


    Who is it for?

    The Gemini System is available to our Data Services Contract (DSC) customers. This includes Shippers, Network Operators, Allocation Agents and Traders.


    What Gemini Entry/Gemini Exit will do for you

    Depending on your role in the industry, you can use Gemini Entry/Gemini Exit to:

    Purchase Gas Capacity (Entry/Exit)
    Check your organisation's Gas Capacity entitlement
    Trade Gas Capacity with other organisations
    Validate your Capacity Invoices
    Sell Capacity back to National Gas Transmission
    Register a Gas Nomination or Renomination at a location (Entry/Exit/interconnectors)
    View measurements/allocations to see the quantity of gas deemed to have flowed through a location

    For more detailed information on what you can do with the Gemini System, please download our Gemini User Role Descriptions.


    Applying for access to the Gemini System

    Gemini works on a role-based system, with each User ID given roles relevant to the duties they need to perform on the system.

    You’ll need to determine your user role by reading the Gemini User Role Descriptions.

    You’ll then need to contact your Local Security Officer (LSO) and ask them to return a Gemini Security Access Request Form (currently v21.8).

    Your LSO will need to request the:

    • creation of your user IDs
    • required roles for your ID

    Your LSO is responsible for all account administration including:

    • creations and deletions
    • permissions and roles
    • password resets

    If you’re unsure who your LSO is, please raise a support request.


    How to log in to the Gemini System

    The Gemini System application is only supported by Internet Explorer 11 (IE11).

    The Gemini System requires the installation of:

    As the Gemini System uses the Citrix application to run, two user IDs are needed:

    • one ID is used to log in to Citrix
    • one ID is configured and used for Gemini


    Gemini Single Sign-On (SSO) User Guide

    We have created a user guide for accessing Gemini and detailing the changes introduced as part of XRN5368.2 – Gemini Single Sign-On. You can download the user guide below.

    Common queries

    The timing of processes within Gemini have changed due to the new switching time. As a result, we’ve created a new ACT file, which sends activity numbers within the file to Shippers.

    Log in to Gemini

    Access the Gemini System through Citrix. 

    Log in


    Gemini maintenance windows:

    Monday to Friday 3:15am–4:15am 
    Sunday 3am–5am

    System outages are updated on our Live updates webpage.

    Raise a support request

    Please raise a support request if you have any queries regarding Gemini.


    Gemini Sustain Plus

    Modernising Gemini through the Sustain Plus programme.