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E-Invoice at Thünen Institute

The Thünen Institute is able to accept and process electronic invoices (e-invoices). Everything you need to know about electronic invoicing with us is described in the following. The necessary information will be enclosed with all new contracts effective immediately.

Starting 27 November 2020, it will be mandatory to submit invoices in electronic form. Exceptions to this rule are given in section 3 (3) of the E-Invoicing Ordinance (E-Rechnungsverordnung, ERechV), for example in case of direct contracts valued at up to €1,000, not including VAT.

We would like to ask you to make use of the possibility to submit electronic invoices. As an issuer of invoices, you can benefit from the advantages even before electronic invoicing becomes mandatory:

  • more efficient work processes, shorter processing times, faster payment
  • quick and easy access to invoice data
  • possibility of digital, auditable archiving
  • lower costs for paper, printing and postage

If you have questions about electronic invoicing for your existing contract with Thünen Institute, please contact the department listed in the contract document.

Submitting E-Invoices

The Thünen Institute receives E-Invoices via the federal Central Invoice Submission Portal (ZRE). You can contact ZRE at

Content of an E-Invoice

In accordance with section 5 of the E-Invoicing Ordinance (and in addition to what is required by section 14 of the Value Added Tax Act (Umsatzsteuergesetz, UStG)), an electronic invoice must include at least the following information:

  • Buyer reference
    The contracting authority will inform you of the buyer reference in document [X] when the contract is awarded.
  • Terms of payment or the date by which payment is due
  • Bank account details of the payment recipient
  • De-Mail or email address of the invoice issuer

Information about invoice content
Please note the following for electronic invoicing with Thünen Institute:

Invoice elementData field XRechnung standardInformation from Thünen Institute for suppliers of goods and services
Buyer reference “Buyer reference” (BT-10)

“This information must be provided with every invoice.”

“Please use the buyer reference provided in the contract document, to be used from the order document that is sent to you in the course of placing the order.”

Purchase order number“Purchase order reference” (BT-13) “Please use the order reference provided in the contract document, to be used from the order document that is sent to you in the course of placing the order. Without it, the Thünen-Institute may reject your E-Invoice.”

Requirements for the invoice format

  • In general, invoices for the federal administration must be issued using the valid XRechnung standard. Other standards may be used (such as ZUGFeRD version 2.1.1 or later in the XRECHNUNG profile) as long as they meet the requirements of the European standard (EN 16931), the conditions of use for the invoice submission portals and the requirements of the federal E-Invoicing Ordinance.
  • Invoice formats which do not comply with the European standard will not be accepted.
  • Supporting documents or attachments should be embedded in the invoice data file; they should not be sent as an email or De-Mail attachment.
  • The maximum size of an invoice depends on the transmission channel selected: for example 10 MB for email and 11 MB for web submission. Please note the portal’s conditions of use in this regard. No more than 200 supporting documents may be embedded. Documents having the following file types may be embedded: PNG, PDF, JPG, JPEG, XLSX, ODS and CSV Attachments must not contain any active content such as macros. Any changes to these requirements will be announced on the invoice submission portal.

These rules do not apply to supporting documents which, according to other laws, must be sent in paper form: export or customs documentation, etc.

Requirements for submitting E-Invoices

  • E-Invoices must be submitted using the Central Invoice Submission Portal (ZRE) at To use the portal, you will first have to register and select the transmission channel you wish to use.
  • For more information, please see the ZRE terms of use.

If you have questions about submitting E-Invoices via the ZRE, the following support is available:

  • Support hotline: available Monday through Friday, 8:00 to 16:00 at +49 228 99681 - 10101
  • Support Email: ZRE users may send questions via Email to 

Invoice issuers and invoice senders with questions about the ZRE may contact its support hotline, which is available Monday through Friday from 8:00 to 16:00 on +49 228 99681-10101.

For more information on the ZRE, please see the brochure Information for invoice issuers and the FAQs on e-invoicing on the website of the Federal Ministry of the Interior, Building and Community:

Legal basis

Under the federal E-Invoicing Ordinance, public administration is required to accept electronic invoices for public contracts, and suppliers of goods and services for the federal administration are required to send electronic invoices. The E-Invoicing Ordinance also sets the deadlines, the transmission channels and the data standard as well as exceptions to electronic invoicing.

Link to the E-Invoicing Ordinance (in German):

For federal contracts, electronic invoicing will be required for goods and services starting 27 November 2020. Exceptions to this requirement are given in the Ordinance and are as follows:

  • invoices for goods and services provided in direct contracts with a value of up to €1,000
  • invoices which meet the conditions for exceptions under section 8 or 9 of the E-Invoicing Ordinance (sensitive invoice data and certain matters of the Foreign Service and other procurement abroad)
  • invoices to be issued in procedures performed by way of an official delegation of powers under section 159 (1) no. 5 of the Act against Restraints of Competition (Gesetz gegen Wettbewerbsbeschränkungen, GWB)
  • Apart from the legal requirement, e-invoicing may be required by the contract in question
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