Question 1

Which verification scope fits my company?

Accepted Answer

The scope depends on your company structure: how many sites deliver to ZF, in how many countries, and how your electricity is sourced. Most single-site suppliers in Germany with a green electricity contract fall under the simplest scope. We help you determine the right scope in a free initial consultation, or you can use our interactive Scope Finder tool.

Question 2

What are EACs, GOs, GECs, and I-RECs?

Accepted Answer

These are all types of Energy Attribute Certificates (EACs) that prove the origin of your electricity. Guarantees of Origin (GOs) are the European system. I-RECs (International Renewable Energy Certificates) are used in Asia, including China. GECs (Green Electricity Certificates) are the Chinese national system. Think of EAC as the umbrella term, and GOs, I-RECs, and GECs as regional implementations.

Question 3

Do I need to repeat the verification every year?

Accepted Answer

No. ZF operates a rotating, sample-based verification process rather than requiring annual re-verification from every supplier, and has not published a fixed re-verification interval. Once verified with a positive result, you are generally compliant for the verified period.

Question 4

Is the verification done on-site or remotely?

Accepted Answer

Remote verification is our standard approach. All document exchange happens through secure channels, and meetings are held via video call. In rare cases where a dedicated meter setup needs to be inspected, an on-site visit may be required.

Question 5

Who pays for the supply chain sustainability audit?

Accepted Answer

The verification cost is borne by the supplier, not by ZF. Effort is measured in auditor days at the current daily rate, and we provide a fixed-price quote before any work begins. ZF operates a rotating, sample-based verification process rather than requiring annual re-verification from every supplier, and has not published a fixed re-verification interval.

Question 6

What if our site is in China? Can you still verify?

Accepted Answer

Yes. We have extensive experience with Chinese suppliers and understand the specific challenges: I-REC and GEC certificate systems, the GEC free text field requirements, and data confidentiality concerns.

Question 7

What is mass balance allocation and when does it apply?

Accepted Answer

Mass balance applies when ZF is not your only customer and you cannot attribute specific electricity to ZF production. The formula is straightforward: ZF Ratio = ZF Sales / Total Sales. This ratio determines how much of your green electricity needs to be verified for ZF.

Question 8

How much does the green energy certificate verification cost?

Accepted Answer

Fees are calculated in auditor days at the current daily rate. A simple single-site verification takes approximately 2 auditor days. ISAE 3000 mass balance verifications require approximately 4 days. We always provide a fixed-price quote before starting.

Question 9

What is the difference between ISRS 4400 and ISAE 3000?

Accepted Answer

ISRS 4400 (Agreed-Upon Procedures) means we perform specific, pre-defined checks on green energy certificates and report factual findings. It is faster and more affordable, suitable for the ZF Recommendation level. ISAE 3000 (Limited Assurance) is a full sustainability assurance engagement required for the ZF Minimum Requirement level (mass balance and dedicated meter). Both are internationally recognized standards for supply chain sustainability audits.

Question 10

Why does justReporting need my revenue data?

Accepted Answer

Revenue data is only needed for mass balance allocation, not for simple green contract verifications. We use total revenue and ZF-specific revenue to calculate the ZF ratio. This data is treated strictly confidentially under our professional secrecy obligations as a licensed German audit firm (WPG).

Question 11

When should I start the verification process?

Accepted Answer

Ideally in Q4 (October to December), before the verification year even ends. This lets you complete the engagement setup and scope definition so you are ready to verify as soon as documents arrive in January. May is tight, as ZF's deadline is 31 May of the following year (e.g. 31 May 2027 for reporting year 2026).

Question 12

What if I don't have all documents yet?

Accepted Answer

That is completely normal and not a reason to delay. We can set up the engagement and define your scope while documents are not yet available. By January, when GO cancellation statements and consumption data arrive, we are ready to verify immediately.

Question 13

When does my energy provider issue the GO cancellation statement?

Accepted Answer

In Germany, energy providers typically issue Guarantees of Origin (Herkunftsnachweise) cancellation statements between January and March for the previous calendar year. For I-RECs and GECs in Asia, retirement statements are available immediately after retirement, which can happen year-round.

Question 14

Can I choose a different verification provider?

Accepted Answer

Yes — but only within limits ZF itself sets. ZF requires the verification of the green electricity share to be performed by an independent public auditor (Wirtschaftsprüfer) or a registered audit firm, applying ISRS 4400 or ISAE 3000 (Revised) / ISSA 5000. Certifications or audits issued by ISO or management-system certification bodies — for example ISO 50001 or ISO 14001 auditors — are explicitly not accepted by ZF for this verification. For ISAE 3000 / ISSA 5000 engagements, any qualified audit firm meeting this criterion can perform the work; for the ISRS 4400 approach, justReporting currently provides this service within the ZF verification framework. We always transparently explain both options so you can make an informed decision.

Question 15

How long is a positive verification result valid?

Accepted Answer

Based on current ZF requirements, ZF operates a rotating, sample-based verification process rather than requiring annual re-verification from every supplier, and has not published a fixed re-verification interval. Treat this as a multi-year investment rather than a recurring annual expense.

Question 16

What does supply chain sustainability audit mean in this context?

Accepted Answer

A supply chain sustainability audit verifies that a ZF supplier's electricity consumption is covered by renewable energy. The direct effect: it supports the decarbonization of ZF's supply chain, reduces the Product Carbon Footprint (PCF) of ZF components, and lowers ZF's Scope 3 emissions. Specifically, we verify Scope 2 emissions (purchased electricity) by matching green energy certificates (Guarantees of Origin, I-RECs, GECs) against actual consumption data.

Question 17

Do you also audit suppliers for other automotive OEMs?

Accepted Answer

Yes. While we are specialized in the ZF verification framework and in direct professional exchange with ZF, the same supply chain sustainability audit under ISAE 3000 or ISRS 4400 works for suppliers of other automotive OEMs with comparable green energy requirements. We do not publish client names without explicit written consent (§ 43 WPO).

Question 18

How does this audit support CSRD / ESRS and Scope 2 reporting?

Accepted Answer

Our verification covers Scope 2 market-based emissions. The verified figures feed directly into your Scope 2 disclosures under ESRS E1, your customers' Scope 3 Category 1 supply chain decarbonization reporting, and evidence for subsidy applications such as Strompreiskompensation. ISAE 3000 is the internationally recognized sustainability assurance standard, so the report is reusable across multiple reporting contexts.

Question 19

What is the difference between Scope 2 and Scope 3 in this context?

Accepted Answer

Scope 2 emissions are indirect emissions from purchased electricity, steam, heating, and cooling — this is what we directly verify at the supplier level. Scope 3 emissions are all other indirect emissions in a company's value chain, including Category 1 (purchased goods and services). The supplier's Scope 2 rolls up into the OEM's Scope 3 Category 1. Verifying a supplier's Scope 2 renewable coverage lowers both at the same time — supply chain decarbonization in a nutshell.

Question 20

Do you offer other assurance services beyond ZF green electricity verification?

Accepted Answer

Yes. We also provide Energieaudits (EnEfG/EED), CSRD/ESRS Limited Assurance, Product Carbon Footprint (PCF) verification, and Strompreiskompensation testates. One engagement can often serve multiple purposes — ask us how to structure it. See also /energieaudit and /supply-chain-audit.

Question 21

Why are you faster than other auditors?

Accepted Answer

Three reasons. First: we work with the ZF verification guideline every day and are in direct professional exchange with ZF — we don't need to learn the requirements. Second: our templates, checklists, and engagement design are ready for day one — no onboarding on your side, no learning curve on ours. Third: we know the markets for green energy certificates (I-REC, GEC, HKN) from practice. That means a lean engagement, fewer clarification rounds, and a fixed-price quote before we start.

Question 22

Which company's figures do we actually verify?

Accepted Answer

Unless you choose group-level scope, verification always centres on the legal entity that holds the ZF delivery contract — not its subsidiaries or sister companies. Electricity consumption and green-electricity certificates of subsidiaries that supply parts upstream are not in scope. If a subsidiary's production is relevant for ZF, we either extend the scope explicitly or structure a separate engagement. We clarify the exact boundary with you before the engagement letter is signed.

Question 23

We didn't apply the ZF redemption note when retiring our certificates — can we still allocate them to ZF?

Accepted Answer

In exceptional cases, yes. Where EACs were already retired before the ZF redemption note could be applied and the retirement can no longer be amended, ZF allows the allocation to be demonstrated by a signed Allocation Declaration (Appendix 9), submitted together with the underlying evidence. It is admissible only where the redemption note was objectively unavailable or could no longer be applied, the omission was not intentional (simply being unaware of the requirement is sufficient), and the relevant quantity is unambiguously identifiable (EAC serial numbers, or generation facility and meter readings) and allocated exclusively to ZF, with no indication that the same electricity is claimed elsewhere. Once you are aware of the requirement, the redemption note must be applied to any certificates retired thereafter. We assess this as part of the verification.

Question 24

Can my ISO 50001 or ISO 14001 certifier perform the ZF green electricity verification?

Accepted Answer

No. Per the ZF Green Electricity Guideline, the verification must be performed by an independent public auditor (Wirtschaftsprüfer) or a registered audit firm applying ISRS 4400, ISAE 3000 (Revised), or ISSA 5000. Certifications or audits issued by ISO or management-system certification bodies (for example ISO 50001 or ISO 14001 auditors) are explicitly not accepted as evidence of the green electricity share.

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