How to tell if a service is actually green

Three different claims are made with the same word, and only one of them means the electricity was clean: renewable supply, renewable-matched, and offset. Telling them apart takes about ten minutes and comes down to one test — does the provider name a facility, a supplier and a figure, or does it show you a leaf?

The three claims, strongest first

Renewable supply

The facility runs on renewable electricity, ideally under a named supply arrangement. The electricity powering the servers is clean at the time it is used.

Providers that have this tend to say so precisely, because it cost them something and they want the credit.

Renewable-matched

The provider buys certificates equal to its yearly use. The certificates are real, but the generation may have happened elsewhere, at other hours — while the facility drew from a fossil-heavy grid at 3 a.m. in February.

This is the most common claim among large providers, and a legitimate thing to do. It is not the same as the first, and it is usually written in language you cannot tell apart from the first.

The tell is the matching period. Ask whether matching is hourly or yearly. Hourly is much stronger, and anyone doing it will say so.

Offset

The provider emits, then pays for reductions elsewhere — forestry, cookstoves, avoided deforestation. Quality ranges from good to worthless, and the weak end of the market has been documented at length.

It is not nothing. But it is a payment after the fact, not a change in how the service runs — and it is often the claim dressed up most enthusiastically.

The five questions

Ask them directly. The quality of the answers separates disclosure from decoration faster than any amount of reading.

1. Which data centre, and where? A named facility and a country. Grid carbon intensity varies a lot across Europe, so the country matters. "Our servers are in the EU" is a jurisdiction answer, not an energy answer.

2. Who supplies the electricity, and on what terms? Named supplier; direct supply, certificates or offsets. Vagueness here is the most reliable warning sign there is.

3. Is matching hourly or yearly? If they know what you mean, that alone is informative.

4. What is the PUE? Power usage effectiveness — the facility's total energy divided by the energy reaching the computers. Efficient modern facilities sit near 1.1 to 1.2. A provider that does not know its figure is not measuring.

5. How long do you keep files, and how many copies? The question nobody expects, with the largest effect. Storage is a continuous cost and copies multiply it — whatever powers either.

Warning signs

• A badge with no registry. Certifications worth having can be looked up. If you cannot, it is a graphic.
• "Carbon neutral" with no scope. Neutral across what? Direct emissions only, or including the supply chain and the hardware — which is usually where most of it sits.
• Tree planting as the headline. Planting and protecting forest is good. It is not a substitute for how a data centre is powered, and when it is the loudest claim it is usually standing in for a stronger one that is missing. I say that as someone who gives a tenth of profit to rainforest protection — a choice, not evidence about electricity.
• No figures anywhere. Disclosure has numbers in it. Marketing has adjectives.
• An undated page. Claims go stale. An undated one tells you nothing about now.

Weighting the answers

Ranked by what actually moves the footprint:

1. Retention and copies — how long, how many. Largest effect, almost never advertised.
2. Energy source — supply beats hourly matching beats yearly matching beats offsets.
3. Grid location — real, second-order.
4. PUE — real, smaller.
5. Everything else — badges, neutrality claims, tree planting.

That is close to the reverse of how these things are usually presented, which is the useful part.

My own answers

Since I am asking you to interrogate providers, here are Yungle's, unflattering parts included.

1. Hydropower
2. Hetzner, Germany · PUE 1.13
3. Your files
4. 10% of profit to rainforest

1. Where: servers at Hetzner in Germany.
2. Electricity: hydropower, per Hetzner. I rent capacity; I do not run the facility or sign the supply contract.
3. Matching: I cannot answer this one first-hand, for the same reason — and I would rather say so than guess.
4. PUE: 1.13, which is Hetzner's figure for the data centre, not a number I measure. Its ISO 27001 and EMAS certificates are Hetzner's too.
5. Retention and copies: one primary copy, not three regional replicas, with nightly backups in EU-jurisdiction storage at a second provider. Free transfers expire after 7 days; paid collections last as long as you like, which is worse on this measure and is a thing customers want.

A tenth of profit goes to Rainforest Trust — a donation, not a claim about electricity. The full list of what Yungle claims and deliberately does not is on the sustainability page.

Applying it

For file transfer specifically, what to look for applies the same checks to this category, and the retention figures for the main services are documented even where energy claims are not. If you are the one writing the vendor form, the procurement checklist turns these questions into a scoring sheet.

And keep the scale in view: cloud storage is a real but modest part of anyone's footprint. The big lever is on your side of the line — deleting what you will never open.