Storage Represents a Green ICT Opportuity
Much Green ICT focuses on computers: servers in the data center and desktops in the office. Don't forget that disk-based data storage, which can cost an organization $25/GB/month, also offers opportunities. Here's a look at the progress manufacturers and users have been making in recent years to manage data storage's energy consumption. The storage capacity of the United States National Security Agency's (NSA) new data center in Utah is a powerful reminder of the role storage plays in ICT facilities.
NPR cites an estimate of five zettabytes (5,000 exabytes) of storage for the NSA facility. Cisco helps us imagine this amount of data by noting that 1 ZB represents the storage of "250 billion DVDs" and that 66 ZB is the "The amount of visual information conveyed from the eyes to the brain of the entire human race in a single year."
Since actual amount of the NSA's storage and any Green ICT tactics being applied to it are classified, let's look at what others have been doing.
As early as 2008, sophisticated users already where aware of the power consumption of hard disk drives (HDD) and thinking about how much performance is really necessary for an application. "Spinning disks consume energy both directly and indirectly. They require energy to spin and generate energy in the form of heat, which then requires cooling systems that consume more energy. So the more spinning disks you have, the more energy you consume. But not all disks consume the same amount of energy. Fast, high-performance disks consume a lot more energy than their slower counterparts."  Marriott International Inc, for example, archives "data that's infrequently accessed onto slower-speed spindles. [VP Wendell] Fox says a disk drive that spins at 7,200 rpm consumes eight times more power than a disk spinning at 3,700 rpm. [IDC analyst Chris] Ingle says Marriott's approach reflects what many other companies are starting to do." 
Storage virtualization can reduce the amount of storage required. A useful PTS Data Center Solutions case study reported that the company's data center successfully used storage virtualization to recover "stranded storage". By significantly increasing data storage utilization, PTS was able to reduce physical storage 21%.
IBM's 2010 Corporate Responsibility Report noted, "Two new storage systems…deliver 88 percent and 85 percent more storage capacity per watt of power consumed than their predecessor models."
Being mindful of toxins in manufacturing and disposal when assessing storage gear lifecycles is another opportunity. Seagate, for example, moved in 2009 to offer drives that no longer use chlorine- and bromine-based chemistry.
The Storage Networking Industry Association (SNIA) has released its SNIA Emerald™ Power Efficiency Measurement Specification “We are providing end–users and the industry at–large with a means to test, measure and evaluate storage system power usage and efficiency at a time when datacenter energy usage is projected to increase by 19% in 2012…The SNIA Emerald Program website will provide the industry with the resources needed to learn about, evaluate, test and submit storage system power usage and efficiency test results…"
The folks at Apple accessories supplier Other World Computing (OWC) called our attention to a number of lower-power storage options they offer, including drives featuring Hitachi CoolSpin, Seagate Barracuda Green, and Western Digital IntelliSeek (variable spin) technologies. The company also reports it has kept six tonnes of polyethylene out of the waste stream by shipping drives in recycled and recyclable packaging. OWC's campus is LEED Platinum certified and 100% wind-powered.
Computerworld reports that the IT department at financial firm State Street "deployed compression and deduplication technologies to reduce storage use by 40% to 50%."
An article in Processor notes, "With average written-data disk utilization rate estimates ranging from as little as 10 to 25%, more than half of the disks quietly humming away in the world’s data centers are effectively wasted." The articles goes on to report, "Microsoft’s research focuses on write offloading that changes the input/output patterns on disks to coordinate idle time when the disks can be spun down to save energy. Researchers have found that this process can result in a 45 to 60% energy savings."
No article on storage would be complete without noting the growing popularity of solid state drives (SSD). We noted above that higher storage performance, like that of 7200 rpm drives, used to mean higher energy consumption, but SSD is different. Tom's Hardware explains, " At the system level, an SSD increases power consumption because CPU and memory utilization rises in response to increased I/O activity (they're not sitting there, waiting on a hard drive to send data). But remember that an SSD-based configuration will always finish those operations faster. You see that reflected in the charts above. At the end of the day, an SSD lowers power consumption." One result is that Seagate announced in 2013 that it is discontinuing production of 7200 rpm HDD while retaining their 5400 rpm line, hoping to migrate power users to hybrid drives (SSHD) that combine solid state storage and spinning storage. Unfortunately, the spinning component is still 7200 rpm.