This translation has not been editorially reviewed yet. The German version is authoritative. Deutsche Fassung

CO₂ & EmpCo

How does your hoster get green energy proof at the Green Web Foundation?

There is a public database for the servers of websites: the Green Web Foundation, a non-profit foundation in the Netherlands, lists hosts there and notes whether they have proven their green electricity. The check asks who hosts the website. If the database has a record for the provider and lists it as “not green”, this finding is raised.

How the check asks

It sends the website’s host name to the interface of the Green Web Foundation. The answer says whether a record exists, which provider is listed there and whether it is listed as “green”, that is, with proven green electricity. A record with the status “not green” results in this finding. If the status is open, the audit file lists that as a separate note.

What it means for the score and the CO₂ value

The CO₂ score loses 8 points; with proof it gains 8 points. In this case the check calculates the CO₂ value per view with 442 g CO₂ per kilowatt hour. With proof, it calculates the data centre share (15 %) with 50 g, about 383 g in total. For the same page, the value with proof is therefore about 13 % lower by this method, because the network and the visitors’ devices still run on the general electricity mix.

What counts as proof

As evidence the Green Web Foundation accepts, for example, an electricity supply contract for renewable energy, documents for a green electricity tariff, guarantees of origin, or proof of own generation off the grid. The provider submits them itself and registers its servers, via domains or IP addresses. The entry is free and then applies to all websites on these servers.

Examples

Claim on the website

Not met

Unsere Website läuft auf grünen Servern.

Passes

Unsere Website liegt bei einem Anbieter, der bei der Green Web Foundation
mit Ökostrom-Nachweis eingetragen ist (Abfrage vom 3. Oktober 2026).

Ask your host about the electricity supply of its data centre: electricity supply contract or guarantee of origin.
Ask it to submit the proof to the Green Web Foundation.
If the proof is still open after your request, move to a provider with an entry, for example Hetzner, which is listed there as “green” (query of 11 September 2026).
After the change, order a re-measurement so that the audit file calculates with the new electricity mix.

Deutsche Fassung dieser Seite

FAQ

What does the entry say about my host?

It shows the state of the database: a green electricity proof is still open there. If your host buys green electricity, it can submit the proof at any time. That is why the first step is to ask.

What if the website is delivered via a CDN?

The check asks about the website’s host name. If a CDN sits in front, the database answers for the CDN provider, because its servers answer the requests. The server behind the CDN is then outside the query.

What does this have to do with the environmental claims on my website?

If your website advertises green electricity for hosting, the check of environmental claims (EmpCo Directive) in the same audit area compares this claim with the entry. With the status “not green”, a separate finding is raised there. If the same sentence names an ecolabel for data centres such as UZ 80 or the Blue Angel, the claim counts as backed.