The rise of social media is being powered by dirty forms of energy such as coal, a report from the campaign group Greenpeace said on Wednesday.

The Clicking Clean report praised six companies – Apple, Box, Facebook, Google, Rackspace and Salesforce – for committing to power their data centres with 100% renewable energy. Apple in particular had cleaned up its energy profile, Greenpeace International said.

But Amazon Web Services, which provides a cloud platform for Netflix, Tumblr and Pinterest, was singled out for being secretive about its energy use, and for siting data centres in areas that rely heavily on coal.

The company lagged "far behind its major competitors, with zero reporting of its energy or environmental footprint to any source or stakeholder", the report said.

Twitter and Oracle were also faulted. Microsoft and Yahoo received middling grades in the report, which looked at energy use by 300 tech companies.

Electricity use by data centres is one of the fastest-growing sources of greenhouse gas emissions globally, as more people come online. Internet data traffic is expected to triple between 2012 and 2017, Greenpeace said.

Companies like Google, Facebook and Apple have built their own clean data centres and pushed for more of that electricity to come from wind and solar power.

But not Amazon, which provides a cloud to many well-known online brands including Netflix, Pinterest, Spotify, Tumblr and Vine, Greenpeace said.

"Amazon has been undergoing quite explosive growth. They are providing a huge part of the infrastructure for the internet," said Gary Cook, technology campaigner for Greenpeace. "But if you look at their data centres, their heaviest concentration is in Virginia which has a very dirty energy grid. They have really done nothing at this point to try to leverage their buying power to secure clean energy."

Power lines and smoke stacks a coal plant. In Virginia, Amazon Web Services has 10 data centres where nearly 40% of its electricity is generated by coal. Photograph: Saul Loeb/AFP/Getty Images

At peak times in the evening, streaming of Netflix and YouTube combined accounts for about 50% of US internet traffic. Much of that traffic is being moved along by electricity coming from coal.

In Virginia, the east coast hub of Amazon's operation with 10 data centres, the company gets just 2% of its electricity from renewable sources. Nearly 40% of its electricity is generated by coal, Greenpeace said.

The findings are estimates; Amazon did not provide data about its electricity demand.

Twitter also received failing grades for failing to disclose its electricity use, despite going public last year. The company rents space in data centres. While it has expanded its footprint in a Sacramento, California data centre with a relatively clean electricity mix, Twitter has also moved into Georgia, a state that relies heavily on coal and nuclear power.

The report said Twitter had made no public effort to buy renewable energy for its data centre, or push electricity providers to provide a cleaner mix of fuels.

An Amazon spokesperson disputed the report, saying Greenpeace "misses the mark by using false assumptions on AWS operations and inaccurate data on AWS energy consumption".

However, Amazon did not address the central criticism of the Greenpeace report about its refusal to disclose energy use - as other tech companies now do.

The spokesperson argued that the use of Amazon's big data centres in itself saved electricity - and lessened the carbon footprint of computing.

"Running IT infrastructure on the AWS Cloud is inherently more energy efficient than traditional computing that depends on small, inefficient, and over-provisioned datacenters."

Carolyn Penner, a spokeswoman for Twitter, said: "Twitter believes strongly in energy efficiency and optimisation of resources for minimal environmental impact. As we build out our infrastructure, we continue to strive for even greater efficiency of operations."

Greenpeace is pressing Twitter and Amazon to follow the lead of Apple, Facebook and Google and press electricity companies to invest in wind and solar.

The evaporator room inside the the new Facebook Data Centre, in Lulea, Swedish Lapland, that is 100% run on hydropower. Photograph: Jonathan Nackstrand/AFP/Getty Images

Facebook had located a data centre in Iowa, ensuring it was powered by wind turbines. In Utah, eBay disconnected its data centre from the grid and brought in fuel cells, powered by natural gas.

"They [Twitter and Amazon] could totally do the same thing," Cook said.

The report also criticised tech companies for their support and their membership of the conservative American Legislative Exchange Council (Alec).

Alec has been pushing for legislation that would impose fees on homeowners who install solar panels, and roll back clean energy standards in many states.

Google, Facebook, Microsoft, Yahoo, eBay, and Verizon Terremark are members of the group.