That's not to say, however, that there isn't a potential for big savings with private clouds. Peterson points out that large agencies could build private clouds and then sell capacity to smaller agencies under a shared-services model.
But for that model to work and produce a strong ROI, government entities will have to move beyond their often parochial outlooks and build a culture that embraces cross-agency cooperation, say Peterson and other analysts.
"If everyone builds their own private cloud, you won't get the cost savings," Peterson says. "The big thing is, we don't want to see a bunch of cloud stovepipes popping up. That's how the government operates now."
Public, Private and Hybrid
Analysts say that government agencies, like their private-sector counterparts, are trying all of the cloud options and seeing which models work best in particular situations.
Government entities that are implementing cloud computing are primarily doing so in one of three ways, according Marie Francesca, director of engineering operations, and Geoff Raines, senior principal software systems engineer, at The Mitre Corp., a government contractor based in Arlington, Va.
One is to use commercial services such as those offered by Amazon and Google. Examples of this model include the migrations of Treasury.gov and Recovery.gov to Amazon's cloud service.
The second is to share services within the government, where one agency acts as a service provider for others. Examples of this are DISA's RACE system and NASA's Nebula.
The third option is to build a private cloud for an organization's exclusive use.
Francesca and Raines point out that government CIOs have such diverse systems in their portfolios that they can legitimately use any of those approaches, depending on the needs of the applications and data slated for migration to the cloud.
The General Services Administration and the National Institute of Standards and Technology are helping federal agencies with their cloud computing moves, according to Francesca and Raines.
The GSA is setting up contract vehicles and schedules that will allow agencies to purchase commercial cloud services in a quicker and more uniform way, they explain. The website Apps.gov will provide a central point for information on this initiative. The GSA had already been providing federal agencies with a uniform mechanism for handling other types of contractors, they say.
Meanwhile, NIST is defining cloud concepts, identifying standards and organizing security research.
Despite such guidance, the reality is that many federal entities aren't yet moving to the cloud.