The Union Registry is an IT system similar to online banking that ensures accurate accounting of EU allowances.

Within it, the individual MOHAs will allow shipping companies to:

  • Record their annual GHG emissions.
  • Check the balance of their account (acquired through auctions or the secondary markets – see Purchasing EU emissions allowances below).
  • Transfer allowances between participants; and
  • Annually reconcile allowances and company-level emissions. 

To open an account, a shipping company will need to send a request to their Administering Authority, providing the information set out in Annex VIIa of Delegated Regulation (EU) 2023/2904. The documentation includes:

  • A contractual mandate (the content of which is specified) for compliance with EU ETS (if not the shipowner)
  • IMO unique company and registered owner identification number of the shipping company
  • Shipping company type, name, country of registration, address, contact details
  • First year of emission
  • Name and IMO unique company and registered owner identification number of the registered shipowner(s) for which the shipping company assumes responsibility for the ETS obligations (if applicable)
  • Name and IMO unique company and registered owner identification number of the person(s) or organisation(s) other than the shipowner, which assumes the responsibilities imposed by the International Management Code for the Safe Operation of Ships and for Pollution Prevention (if applicable) 

For further details on opening a MOHA, see EU FAQs on Buying and surrendering allowances in the Union Registry.

For further details on the functioning of the Union Registry see Union Registry - European Commission ( 

Purchasing EU emissions allowances

These may be purchased via:

  • The primary market through auctions on the European Energy Exchange (EEX) (currently contracted to manage this system); and/or
  • A secondary market in which allowances can be sold bilaterally or through various derivatives provided by financial institutions and transferred directly into the Union Registry account. 

EU allowances (EUA) issued on or after 2013 do not expire and may be banked for future years. However, an allowance that has been surrendered cannot be retrieved.

Deadline for surrendering EU allowances

By 30 September 2025, shipping companies must surrender sufficient EU allowances via the MOHA to the AA, to account for total emissions released at the company level as reported in 2024 (after applicable derogations as stipulated in Directive 2003/87/EC have been applied). 

Information on key compliance dates