There is a good article over at Infoworld on the colo market and companies outsourcing their data center needs. They also discuss making ice at night to cool in the day, fly wheel replacments for a UPS, and increasing efficiency through the usage of DC power. The first paragraph sums it up nicely:
"Data-center space is in high demand these days, and like energy prices, that demand appears to be headed nowhere but up. In fact, Digital Realty, a San Francisco-based REIT, estimates that demand for data-center space will continue to rise by as much as 15% annually over the next five years."
Check out the article here.