This article was written by Oilprice.com -- the leading provider of energy news in the world. Also check out these recent articles.

Amazon (AMZN -1.65%) and Twitter (TWTR) have received "Fs" on their renewable energy report cards issued by Greenpeace, for inadequate commitment to renewable energy as a large percentage of Internet traffic remains powered by dirty energy.

According to a Greenpeace report released on Wednesday, only 15% of Amazon's massive Internet traffic is powered by green energy, while Twitter, which doesn't use energy hungry data centers, has a long way to go in making its micro-blogging service more efficient and energy transparent.

Apple, Google, and Facebook caught the flip side of the report, with Greenpeace noting that these companies had made significant progress in adopting renewable energy sources to power their web services.     

Apple was given an "A" for efforts in transparency, renewable energy policy and renewable energy deployment, up from Ds and Fs from the last report two years ago.  The improved grading represents Apple's construction of an on-site solar panel farm and fuel-cells at its North Carolina data center, as well as the direct procurement of renewable energy sources at its other three facilities.  

Amazon—which accounts for 1% of all Internet traffic--scored an "F" in terms of commitment to renewable energy, where it locates its data centers and environmental advocacy, while the company was given a "D" in energy efficiency.

Greenpeace noted that unlike Apple, Google and Facebook, Amazon was not "motivated" and indeed was working backwards, citing the example of its Umatilla Electric Cooperative in Oregon, which is pushing the state to loosen environmental restrictions.

"We haven't seen a change in Amazon," Cook said in a statement. "Unfortunately, unlike many of those in the sector, they've not moved very much in the past few years."

Some Internet companies "have refused to pay even lip service to sustainability and are simply buying dirty energy straight from the grid," said the report. "Those companies, most notably Amazon Web Services, are choosing how to power their infrastructure based solely on lowest electricity prices."

In a statement emailed to various news agencies, Amazon the Greenpeace report "misses the mark by using false assumptions", and that the company operates "efficient and highly utilized data centers" in 10 AWS regions across the globe, and two of those use 100 percent carbon-free power."

Greenpeace said Twitter is lagging behind Salesforce.com, inc. (CRM -1.10%) and Box, which have demonstrated their commitment to renewable energy. Twitter was given an "F" for transparency, energy efficiency mitigation, and renewable energy deployment and advocacy and a "D" for renewable energy commitment and sitting policy.

"Twitter's lack of transparency makes it impossible to know what, if any, notable efficiency measures the company employs," according to Greenpeace.