Dublin, Ireland and Chicago are the sites for two new Microsoft datacenters that employ some green innovations. Both are set to go online in next month and each drives energy efficiency in different ways.

The Dublin datacenter, a render of which you can see above, is a 330,000 square foot facility that will keep cool by employing outside air thereby lowering energy costs. Chicago, on the other hand, opts for massive density via the datacenter-in-a-box/container route for its 700,000 square foot site.

The Chicago, Illinois facility covers over 700,000 square feet–approximately the size of 16 football fields–with critical power of 60 megawatts. Phase 1 represents 30 mega watts of critical power and the rest is pre-positioned for future growth. Two-thirds of the Chicago data center is optimized for housing containerized servers. Containers conserve energy and will help us realize new advancements in power efficiency with a PUE yearly average calculated at 1.22. These prepackaged units (with up to 1,800 to 2,500 servers each) can be wheeled into the facility and made operational within hours, so they represent important advances in the ability to quickly and efficiently provision capacity. The density inside the containers can exceed 10 times that of traditional data centers.

Sun got in early with the concept, but IBM, Dell and others have since made modular datacenter moves of their own.