In a new report on Thursday, Greenpeace ( said that while Apple is doing a better job ensuring the energy efficiency of its data centers, the company still lags behind some competitors in key areas.

However, Rich Miller of Data Center Knowledge (DCK), an online source of daily news and analysis about the data center industry, says ( the environmental group is too critical in its grading of Apple and is apparently making up its own estimates of the North Carolina data center’s energy usage rather than believing Apple’s public statements.

Greenpeace says that additional information Apple provided about its facilities in recent months has resulted in improved scores. That includes infrastructure siting, where Apple now has a “D” grade, up from an “F.” Apple also improved from “D” to “C” ratings in energy efficiency and greenhouse gas mitigation, as well as renewable energy investment and advocacy.

In mid-May Apple announced its intention to operate its Maiden, N.C., data center entirely off renewable energy by the end of 2012. Greenpeace praised Apple for the pledge but chided the company for what it says has been a lack of transparency on the road map to reach that goal.

“In its initial report in April, Greenpeace estimated Apple’s power use in North Carolina at a whopping 100 megawatts,” Miller writes. “The group has reduced that slightly to 81 megawatts, dismissing the company’s disclosure that it expects draw about 20 megawatts at full capacity. Strangely, the Greenpeace report notes that Apple currently has state permits for backup generators providing up to 41 megawatts of power — a data point that suggests Greenpeace’s estimate is significantly off base. Greenpeace’s math assumes that Apple is providing only enough backup power to support half of its total power requirement, a configuration inconsistent with industry practices.”

He concludes that either:

“Greenpeace is having difficulty developing estimates that accurately incorporate data center operations and power usage.”
“Greenpeace is predisposed to cling to estimates that make Apple look less “green” because it generates more headlines for its awareness campaigns.”