Just in time for Earth Day, Greenpeace published a report Thursday on cloud computing that asserts Apple is the company with the dirtiest data.

The report looks at the practices of several tech companies that rely on cloud computing and scored the companies on coal power use, policy transparency, data center sites and how the companies offset their energy use.

According to Greenpeace, Apple’s low marks were mostly due to the amount of energy its new North Carolina data facility is expected to consume.

Apple didn’t respond to a request for comment.

Yahoo and Google topped their list, followed by Amazon Web Services, Microsoft, Twitter, Facebook, IBM and HP.

(The report, based on publicly available data, also examined Akamai but could not come up with a figure for its coal consumption.)

One particularly interesting tidbit from the report: If cloud computing were a country, it would be the fifth-largest energy consumer in the world, behind Japan and ahead of India.

Today, Google announced that it has signed a power purchase agreement for wind energy in Oklahoma. It is the second wind energy deal Google has made — it signed a similar deal in Iowa last July — as part of its commitment to be a carbon neutral company.

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