First, understand that storage is not the major culprit in the data center. IT equipment accounts for about 50% of energy consumption and storage about 20-30% of that piece of the pie. So overall, storage accounts for about 10-15% of the problem. Nonetheless, disk drives are a major culprit of storage power consumption and for those who are desperate – out of power or cooling - the best strategy is to deploy lower RPM drives and look to water cooling if possible.
For those who are not desperate, the best strategy is to wait for the vendors to commit to their green storage strategies while addressing the organizational issues discussed in Can IT be cool again?.