Going Green with Desktop Virtualization

By Aly Orady
published: Friday, April 10 2009

New Dawn of Virtualization

According to a recent McKinsey and Company report, data centers emit 0.3 percent of the world's carbon dioxide emissions.  As the use of virtualization in data centers becomes more prevalent, the green benefits including the significant savings on cooling and power are becoming more well-known. While organizations continue to adopt server virtualization for data center consolidation - with Gartner predicting that there will be 4 million virtual machines installed on x86 servers by 2012 , - virtualization technologies are being leveraged in broader IT beyond just the server. Desktop virtualization, for example, is seen as one of the strongest areas of growth. Gartner predicts the number of virtualized PCs to grow to 660 million by 2011 . Traditional PC desktops certainly represent a far larger cost center - from initial acquisition and maintenance costs to the green impact - than the datacenter. Moreover, a 2008 study from The Climate Group approximates that PCs consume around three times as much power as the data center.

Desktop Virtualization

Just as server virtualization is not a new, but rather a renewed concept, desktop virtualization also has existed in previous forms. Companies like Citrix, Microsoft, Sun Microsystems, Wyse and HP have long been in the business of leveraging the power, security and manageability of servers to host desktop applications and distribute them to alternative desktop clients.

However, instead of hosting desktop applications on server operating systems that look, act and are managed differently than PCs, the new wave of solutions use hypervisor technologies from companies like VMware, Citrix and Microsoft to host multiple instances of Windows XP or Vista in the data center and then connect the display, keyboard, mouse and USB peripherals over the network from a desktop device.

This strategy, called desktop virtualization, results in better management savings than associated with thin clients by enabling far easier deployment and management in the data center and eliminating many of the application compatibility and end user retraining issues. Most importantly, the end user desktop experience is unchanged and end users can keep the same OS configuration they had with their traditional PC.  In addition, many desktop virtualization solutions do not have the technical limitations of thin clients and do not require unique skills or software to enable all the utility of the Windows experience including management and drivers.

Green Savings and Server-based Desktop Virtualization

Saving Power

The initial savings from server-based desktop virtualization solutions are similar to those experienced in server consolidation. One of the greatest benefits of server virtualization is the energy saved when many servers running multiple application loads at low utilization can be combined on one physical piece of hardware. Because server-based virtual desktops run from the data center, power savings are twofold: server-based virtual desktops allow organizations to further consolidate and save on power and cooling in the data center. Additionally, since most virtual desktop client devices have significantly smaller power footprints than their PC-counterparts - as little as just four watts versus over 150 watts for a traditional PC - organizations save power on the desktop.

According to an Environmental Protection Agency (EPA) report to congress, data centers consumed about 60 billion kilowatt-hours (kWh) in 2006, which was around 1.5 percent of the total U.S. electricity consumption for that year . The EPA also has calculated that if all computers sold in the United States met the Energy Star requirements, the total savings in energy costs would be around $2 billion. With a cut in greenhouse gas emissions that would be equivalent to removing 2 million cars off the road . If businesses replaced their PCs with server-based desktop virtualization, these savings would dramatically increase.

For example, a desktop device optimized around delivering a virtual desktop like the Pano Logic desktop virtualization solution uses only 18% of the energy of the average PC, including its share of the server's power and the energy consumed by a traditional desktop computer. Even when in sleep mode, most desktops consume around 35 watts compared to the Pano device's average of less than 5 watts when powered on. This is a very real savings both in the environmental impact of a company's operations as well as their energy budget.

Due to the potential energy savings, some energy companies have created rebate programs as incentives to encourage organizations to adopt virtualization technologies. One example is the western US based utility company, Pacific Gas and Electric (PG&E).  PG&E offers rebates of hundreds of dollars per server replaced through virtualization initiatives. They also allow for companies to submit other green IT initiatives for possible rebate and provide free energy audits so that companies can track what they save.

E-waste and the virtual desktop

Traditional PCs have other environmental drawbacks in addition to their power requirements: their size and their relatively short lifecycle.

Of the just over one billion PCs used around the world, around 180 million PCs will be replaced this year. A fifth of these will be dumped into landfills. Some international disposal sites incinerate discarded PC technology which further pollutes the air with toxins. E-waste is a growing global issue. Millions of computers are discarded into landfills and many of the raw materials used in their manufacturing like lead, cadmium, mercury and chromium are harmful if they seep into soil and groundwater.