As a manager of nearly 10,000 federal buildings across the country, the General Services Administration (GSA) is in a unique position to move the needle on energy use within the government. 

In order to fulfill an executive order setting energy performance goals in government buildings, the GSA recently started a "green proving ground" to test out energy efficiency and renewable energy products for wider adoption across its portfolio of buildings. The proving ground is like American Gladiators for energy-efficient products, where technologies are put to the test in a variety of conditions. 

Well, actually, it's not nearly as exciting. But it's certainly far more important.

In partnership with government labs, the GSA is installing all kinds of systems in its buildings -- variable speed chillers, wireless sensor networks, on-site water treatment andsolarPV, among many others -- to determine which ones are suitable for widespread adoption. The testing has validated a wide set of technologies that, if implemented on a broader scale, could offer deep energy savings across thousands of buildings.

Here are five of the most recent technologies the GSA has tested and validated.

Solar PV

In order to test the viability of solar on its buildings, GSA installed five PV systems at Bean Federal Center in Indianapolis, Indiana. One of the projects was a 2-megawatt crystalline PV project system, and the other four were 3-kilowatt test installations (including a system from Solyndra).

After a year of testing, the 2-megawatt system offset 8 percent of the federal center's electricity consumption, and the GSA concluded the payback period would be nineteen years at the Midwest location. All the systems performed as expected or better than expected, leading GSA to conclude that solar "is a practical, on-site energy generation solution, even in a diffuse, four-season climate" like Indiana.

Occupant responsive lighting

Rather than simply test out "dumb" efficient lights, GSA wanted to know how much controllable lighting systems that respond to occupancy would save. GSA deployed seven such systems in vastly different occupancy conditions across five buildings. Each lighting system included a management control system that responded automatically to occupancy levels or a manual override that allowed building mangers and individuals to change lighting conditions in local areas.

GSA found that controllable lighting offered energy savings of between 27 percent and 63 percent, depending on the location and occupancy conditions. GSA also found through surveys that "occupants were generally more satisfied with the retrofitted lighting systems," leading the agency to call for widespread adoption of smart lighting.

Advanced power strips

Plugs that suck electricity all day and night can account for up to one-quarter of electricity use in office buildings. This adds up to a major expense across the GSA's portfolio of 9,600 buildings. Advanced power strips that can adapt to load automatically or that allow users to schedule circuit use can drastically cut plug loads.

The GSA tested nearly 300 advanced power strips (APS) in eight buildings throughout the Mid-Atlantic region and found that the technology reduced plug loads by 26 percent at computer workstations and by half in printer rooms. The scheduled timers performed the best, bringing in average energy savings of nearly 50 percent. The payback period is even more impressive, with kitchen timers recouping their costs within half a year and printer rooms paying themselves back in just over a year. GSA concluded that "energy savings and low simple payback argue in favor of deployment of APS...throughout GSA’s portfolio."

Variable refrigerant flow

This technology uses refrigerants as a way to heat or cool buildings through a modular HVAC unit. By running multiple lines to fan coils, all of which can be controlled as individual units, the system allows for more granularity in heating and cooling a building. The technology is particularly attractive in older buildings where adding new air ducts is difficult.

GSA's evaluation found that variable refrigerant systems could save government buildings 34 percent or more on heating and cooling costs. The buildings best suited for this technology include those with limited space for new ducts, those in colder climates and those that require mixed temperature controls. Although GSA concluded the technology "merits serious consideration," the high upfront cost and limitations in certain buildings don't make it attractive everywhere.

Condensing boilers

Condensing boilers utilize waste heat to preheat water coming into a tank. This technology is big in Europe where some countries mandate its use, but is less popular in the U.S. The GSA recently installed four natural gas condensing boilers at a federal office building in Atlanta, reducing natural gas consumption by 14 percent over a six-month period of time. GSA estimates that installing condensing boilers across its entire portfolio could reduce total energy use by 1 percent, with a payback of roughly five years and almost no increase in operations and maintenance costs. "Replacing conventional boilers that are at end-of-life with condensing boilers should be considered during all facility energy audits," the GSA bullishly concluded.

The GSA is under increasing pressure to get its energy use and carbon emissions down. These are just a handful of the proven technologies the government can use to meet sustainability targets.