A recent report by Greenpeace said that Apple, Amazon and Twitter are among the companies using "dirty" cloud computing technology that relies on coal and nuclear power. The social media giants were graded poorly on the study, which focused on how companies of their size use clean energy to power the mushrooming Internet cloud. Greenpeace found that Facebook, Google and Yahoo! were demonstrating environmentally friendly cloud computing practices. The report, titles "How Clean is your Cloud?" focused on the companies' use of data centers and other energy issues. "We are not trying to give them a hard time, we are trying to build them up to do the right thing," Greenpeace senior campaign specialist Casey Harrell said. "We love our iPhones, they make our lives better but they shouldn't make the planet worse," he added. Christy Ferguson, who heads Greenpeace Canada's Climate and Energy Unit added that the world is becoming increasingly reliant upon cloud technology. Cloud technology enables users to watch movies or TV, listen to music, work and share photos without saving information to their hard drive or local network. The world's largest cloud computing data centers are located in countries such as Ireland, Germany, Hong Kong, the Netherlands and across the United States. Greenpeace alleges that these centers "Are powered by the dirtiest sources of electricity, supplied by some of the dirtiest utilities on the planet, such as gas, coal and nuclear power." The report said Amazon's cloud technology has relied upon coal (33.9%) and nuclear power (29.9%). It gave the company a grade of "F" for energy transparency, renewable energy and green advocacy. Follow Ynetnews on Facebook and Twitter