If one of the underlying tenets of thinking ecologically is to conserve resources, then Miami-Dade County Public Schools is thinking green two times over.

Not only did it deploy an IT system that does scheduled shutdowns of 80,000 computers across 370 sites, but it did so by reusing software originally designed for patch management.

Truth to tell, the fourth-largest school district in the United States got a little help from BigFix, the vendor that Miami-Dade has been using since 2004 to manage the desktop PCs accessed by a population of 345,000 students and 22,000 teachers in a total of 400 schools and administrative sites.

[Discover the techniques used by other 2008 Green 15 winners to make their IT more sustainable. ]

Because every device is already connected to the asset and patch management system, Miami-Dade was able to leverage the management technology that pushes down software updates and use it to also control when computers are turned on and off.

Additionally, because the BigFix system was already in place, it cost Miami-Dade only $2 more per desktop to add the power management component.

Tom Sims, director of network systems at Miami-Dade, said the district's electric bill of $80 million a year made centralized power management for PCs a no-brainer. Sims said the system allows PCs to be shut down according to a schedule for each site in the school district.

"Some buildings have night schools, so we work from template-driven parameters, especially the off and on hours for schools with adult classes," said Sims.

The system is managed through a console layered on top of an SQL database. A separate component queries the database and sends out reports on PC usage and associated costs based on cost per kilowatt hour.

All told, the power management system has cut the time that PCs are turned on and consuming electricity by about half, down from being kept on for an average of 20.75 hours per day to 10.3 hours per day. When the system shut down almost all of the PCs during spring break, Miami-Dade saved $1 million for that week alone.

In terms of comparing the district's power consumption to nationwide averages, Miami-Dade went from being in the 35th percentile, at $461,655 per month, to the 4th percentile, at $243,157 per month.

Sims estimates that PC power management will save the district at least $2 million per year, but he isn't stopping there. Now Sims is investigating how to link the system into an overall energy management system that controls the HVAC systems as well.