Greenpeace has issued a video calling on social networking giant Facebook to stop powering its Oregon data centre with electricity generated by burning coal.

In July 2010, Facebook announced that it would be doubling the size of its 147,000 square foot data centre in Prineville, Oregon. This announcement prompted the environmentalist pressure group to write an open letter to Facebook founder Mark Zuckerberg.

The letter criticised the company’s “decision to power this data center with dirty coal-fired electricity from PacificCorp, which runs an electricity mix that is disproportionately powered by coal, the largest source of global warming pollution.”

Facebook’s director of policy communications Barry Schnitt responded to Greenpeace’s open letter, arguing that by centralising its data centre operations in Oregon, with its “uniquely dry and temperate climate”, the company has been able to achieve a Power Usage Effectiveness (PUE) of 1.15. The average PUE in the web industry is between 1.7 and 2, he said (although PUE is not designed as a measure to compare data centres).

“It’s true that the local utility for the region we chose, Pacific Power, has an energy mix that is weighted slightly more toward coal than the national average (58% vs. about 50%),” he wrote. “However, the efficiency we are able to achieve because of the climate of the region minimizes our overall carbon footprint.”

Now Greenpeace has responded with the following video, in which it calls on Facebook to increase the use of wind-generated electricity and describes it as a “so coal network”.

In August 2010, it was rumoured that Facebook was to become one of the first companies to use chips based on the ARM architecture – most commonly found in mobile devices – inside its servers in order to reduce power consumption. The company denied this claim, however.