Greenpeace has given Apple a minor upgrade in its clean power rankings, saying the company has improved its infrastructure siting, energy efficiency, and use of renewable energy since April. However, Apple wasn't exactly scoring well before, earning a F, D, and D in each of the aforementioned categories, which have now been boosted to a D, C, and C grade.

The environmental advocacy group says that Apple must improve its reliance on Coal for iCloud data centers. Greenpeace applauds Apple's statement that it wants to power three of the centers with 100 percent renewable energy by 2013, but says that it shouldn't cheat by using coal and selling power back to suppliers for "renewable energy credits," instead pointing to alternative suppliers that would actually provide clean energy. It also wants Apple to commit to similar standards for its upcoming Reno, Nevada data center and all future sites.