Apple has come bottom of the most comprehensive green league table of technology companies because of its heavy reliance on "dirty data" centres.

The list, which is compiled by Greenpeace and released in San Francisco on Thursday, shows that the company relies heavily on highly polluting coal power at the sites that house its banks of servers.

Greenpeace's report, How Dirty is Your Data? reveals that the company's investment in a new North Carolina facility will triple its electricity consumption, equivalent to the electricity demand of 80,000 average US homes. The facility's power will be supplied by Duke Energy, with a mix of 62% coal and 32% nuclear. On Wednesday, Apple posted a large boost in quarterly earnings, which grew by 95% to $6bn (£3.65bn).

Gary Cook, Greenpeace's IT policy analyst and lead author of the report, said: "Consumers want to know that when they upload a video or change their Facebook status that they are not contributing to global warming or future Fukushimas."

Companies in the US are not required by law to disclose their energy use or carbon emissions. But Greenpeace drew on publicly available information on investments made in data centres, to estimate the maximum power these facilities will consume, and matched that information with data from the government or utilities.

The report estimated dependence on coal for Apple's data centres at 54.5%, followed by Facebook at 53.2%, IBM at 51.6%, HP at 49.4%, and Twitter at 42.5%. Top marks in Greenpeace's clean energy index went to Yahoo, followed by Google and Amazon. Greenpeace is also campaigning for Facebook to "unfriend coal" and use cleaner energy to power its servers.

Cook said: "Many companies treat their energy consumption a bit like the Coca-Cola secret formula, because they don't want competitors knowing how much they spend on energy. The amount of electricity they consume would give some indication of what kind of arms race they were in. They don't really want this story to be told."

Cloud computing relies on large data centres, rather than in-house based IT services, to power internet-based services such as Hotmail or Gmail. Data centre energy demand already accounts for 1.5% to 2% of world electricity consumption and is set to quadruple over the next 10 years.

Molly Webb, head of smart technology at the Climate Group in London, said: "Greenpeace is calling for transparency from companies which rely heavily on data centres, and that would ideally highlight the need for investment and ambitious government policy to ensure enough clean power is available to green our tweets."

Jonathan Koomey, a project scientist for the End-Use Forecasting Group at Lawrence Berkeley National Laboratory, whose work was cited in the study, said that the IT industry wrongly attracted criticism: "The use of IT often reduces environmental impacts. When we compared greenhouse gas emissions for downloading music to buying it on a CD, for example, we found downloads reduced emissions 40-80%."

Apple declined to comment on the Greenpeace report. But at its last shareholder meeting, Apple CFO Peter Oppenheimer said the company would have more to say on the new data centre in Maiden, North Carolina, in the spring.