The greening of data centers most likely will not come due to pressure from government or environmentalists or even customers, but because it makes good business sense. Sustainable and scalable data center infrastructure can pay itself in less time due to the overall foot print and the inherent higher energy use. Conversely, profits will deteriorate if overhead cost cannot be contained. And where much energy is wasted on environmental systems rather than on profitable computing, the value of providing high performance infrastructure grows even greater.    

Data Centers and Telecom
Manage design and construction for new and existing Data Centers. Intuitive adaptation of existing facilities to increase infrastructure performance.  
More on Data and Energy Use

Google Data Center Summit
Interesting information regarding the evolution of data center infrastructure efficiency.