By starting with an existing building and recycling 90% of its materials and 95% of the shell of the building IBM got a great start to the development of their new green datacenter in RTP and the awarding of LEED Gold certification. From the reflective roof (to reduce cooling requirements) to the innovative rainwater collection and recycling system (to be used in cooling) the new datacenter does an excellent job of showing what can be done with brick and mortar datacenters.
But it's important to note that the internal construction of the new datacenter makes use of IBMs Enterprise Modular Data Center architecture. This choice is indicative of what the future holds for datacenters in general; the concept of modularity. Modularity isn't just for the container market, or barebones datacenter construction.
The ability to deploy an infrastructure that can expand or contract to meet the business needs, while neither over nor underutilizing the systems needed to deliver the power and cooling to the IT workload is the goal. The modular model allows even brick and mortar construction in a traditional building to be designed in a way that the customer invests in the architecture that allows computing power to grow and change with the business needs without the need to have expensive equipment sitting idle while waiting for the business to grow into it.
IBM makes claims that up to 40% of capital cost and 50% of operational expenses can be saved by using their modular model, with the expenses being deferred until the additional capacity is necessary. Data center modules can be had from a number of vendors, in configuration from single modules, to predesigned containers, to entire modular datacenters.
IBM's experience shows it is possible to use modular components as the core of your datacenter redesign, but keep in mind that even a less bare bones rebuild of an existing datacenter can benefit from the addition of modular elements, either as new components or to replace existing standard rack systems in current datacenters.