Notes for audit reports for the biogas register

The structure of the audit report can have great influence on the speed at which the verification (greenlighting) of a batch of methane takes place. Hence, dena recommends that the structure of the audit report follows the system used by the biogas register. This simplifies processing and allows a batch to be given the green light quickly.

Hence, the following contains tips on how audit reports can be structured so as to match the system used by the biogas register.

This content can also be downloaded in the document box.

1. Background: Audit reports in the German biogas register.

The German biogas register was created as a documentation system for biogas records in the natural gas grid. Audit reports (also called audit documentation / audits) on biogas facilities and/or biogas quantities are stored in the biogas register. In legal terms, these audit reports serve as the original record which, above all, is required when submitting applications for reimbursements or rebates, as well as fulfilling record-keeping obligations for biogas in the natural gas grid. The process according to which facilities and biogas quantities are entered into the biogas register is as follows:

  1. The user provides information on a biogas facility or quantity in the register
  2. The auditor verifies the information provided by the user during an expert audit and uploads the corresponding audit report
  3. The user submits the information he entered, which has now been verified by the auditor, to the registrar
  4. The registrar performs a plausibility check based on the information provided and the audit report
  5. The result is that the facility or biogas quantity is permanently entered into the system ("greenlighted")

At the same time, the auditor confirms in the biogas register that the information provided by the user corresponds to the content of the audit report, i.e. that they were corroborated during the audit carried out on site.

2. Separate facility- and company-related audits.

The German biogas register distinguishes between the documentation of facility and company audits. The documentation of a facility audit includes those inspections which pertain to the facility, and which may therefore be valid for a longer period of time. The documentation of a company audit includes those inspections which pertain to a certain quantity of biogas. These quantities must be unambiguously defined in the description, both with regard to its energy content in kWh as well as with regard to the injection period.

Note: When compiling the audit report, two separate reports should be compiled; one for facility-related inspections and one for company-related inspections, in order to facilitate the conducting of plausibility checks for the registrar. However, the registrar also accepts the same audit report for both the facility as well as the quantity inspections.

3. Following the criteria catalogue.


The inspection requirements necessary according to German law for various reimbursements, record-keeping obligations, and rebates
are summarised in the criteria catalogue of the German biogas register. Based on
these criteria, the documented biogas facilities and quantities will be distinguished according to
their properties. Hence, a distinction is made between facility- and company-related criteria.
Note: The (inspection and) structure of the audit report should be adapted to the individual points of the criteria catalogue.

The legal background of the criteria catalogue is described in the document "Suggestion for a documentation system for biogas characteristics".

4. Adherence to mass balancing regulations.

The interpretation aid for mass balancing according to Section 27c (1) No. 2 of the 2012 Renewable Energy Sources Act (EEG) (hereinafter: interpretation aid) describes requirements for mass balancing systems, which are binding for legally valid mass balancing and hence are adhered to by the German biogas register, which is a mass balancing system.
Due to this, it must be possible for the auditor to verify the numerically correct transfer of the quantity of biomethane handed over to the transport customer at the grid connection point in a specified period of time up to the 1st documentation point both in the audit report as well as the biogas register (via criterion 27).
If there is a transfer of rights for the entire processed quantity between two or more legal or natural persons between the biogas processing, the grid connection point, and the actual injection (1st documentation point), the audit report must confirm every single transfer of rights, including the quantity transferred, such that only the final legal or natural person in possession of the quantity of biomethane before the 1st documentation point needs to document these quantities in the register. In the case of a division of the overall processed quantity or the absence of confirmation of a legal transfer in the audit report, the legal or natural person who was last named in the audit report as being in possession of the overall processed quantity is obliged to maintain documentation in the biogas register.

Note: In addition, in cases where various gaseous biomass products from different raw biogas production facilities are processed in a jointly used biogas production facility, we recommend that the audit report provide verification of each individual partial raw biogas quantity, stating the quantity and all legal and natural persons involved in its production and processing.

5. Information for the greenlighting process.

In particular, the information to be entered by the user and to be confirmed by the auditor includes:

  • Information on biogas facilities
  • Information on biogas quantities
  • Name of biogas facility
  • Audited (verified) facility-related criteria
  • Audited (verified) company-related criteria
  • Client of audit report
  • Name of company which produces biogas in this facility
  • Meter number and injection point (according to definition for the designation of real
  • metering points by the German Association of Energy and Water Industries (BDEW))
  • Year or time of commissioning injection quantity in kWh (when auditing multiple partial quantities, it is necessary to specify each individual quantity)
  • Time of first validation of this audit
  • Production period (accurate to the day; information accurate to the minute may be specified; when auditing multiple partial quantities, it is necessary to specify each individual quantity)

Note: These points should be listed in a summary or highlighted in the text of the audit report.

Obligatory fields: The "General contractual terms for users" (Number 2.4) point out that audit reports for biogas quantities are to specify which partial quantities of the biogas quantity audited are to be managed via the biogas register. This information prevents multiple sales because the record with this audit report can only be managed via the biogas register. Hence, the audit report must contain information on which (partial) quantities in kWh are to be represented and documented in the German biogas register.

6. Information on audit firm and auditor.

The registrar also verifies if the audit report contains information on the auditor and/or the

audit firm for which the auditor was working, as well as the date and location where the audit report was compiled.

Note: These data should be included in the report.

7. Handling of sensitive information.

The audit reports submitted will be stored in the biogas register and can also be viewed by third parties
along the entire record-keeping chain upon request. For the relevant regulations, please refer to the "General information on how the German biogas register works". The following refers explicitly to the above.

The auditor is to have the client give him explicit consent and assign him the job of uploading the audit report to the biogas register; also see section 1.1.3 in the "General terms of use for audit firms and auditors".

Note: If the audit report contains sensitive information which is not relevant for the record, they do not need to be included directly. Such information may include e.g. the auditor's recommendations for internal processes. In this case, such information may be provided on a separate annex to the audit report (which is then not disclosed to other parties). Alternatively, such information may be blacked out before being uploaded.

8. Transitional regulations for existing audit reports.

Audit reports which do not fulfil content-related requirements because they were e.g. compiled in the past
can be updated with the required information with the aid of an additional document. To do so, the auditor compiles an additional document which adds information which is incomplete or missing from the audit report, such that it fulfils the content-related requirements. Furthermore, he is to provide personal information in this document, organisation-related information on the audit firm for which he is working, as well as information on the date and location the document was compiled. The relationship to the audit report to be supplemented should also be clearly stated. This document will be stored together with the original audit report in the German biogas register.

9. Supplementary audit of quantities which have already been documented.

Starting with version 2.0 of the biogas register, it is possible to expand the property profile of parent batches that have already undergone a plausibility check ("greenlighted") with additional criteria. The basis for this is an audit report (audit document) from a registered auditor, in which the new criteria to be added are verified according to the 2012 Renewable Energy Sources Act (EEG). In contrast to register version 1, the new version allows parent batches to undergo the greenlighting process multiple times in order to add additional criteria.
However, the new criteria will only be transferred to batches which continue to exist in the system and not to batches which have already been withdrawn ("redlighted").