By Summer BarkleySeptember 29, 2011
BAGRAM AIRFIELD, Afghanistan--How to heat and cool in the desert without attempting to heat and cool the desert itself is a question that has to be answered when planning and building camps and operating bases in Afghanistan. The easy answer is generators and then more generators.
Another answer is offered by Project Manger-Mobile Electric Power (PM-MEP) in the form of the Afghan Microgrid Project, or AMP. Forward engineering support of the project is provided in part by the Research, Development and Engineering Command's Field Assistance in Science and Technology - Center nested in the 401st Army Field Support Brigade. The 401st AFSB, working through its parent, Army Sustainment Command, delivers integrated logistics solutions to operating forces -- in this case reliable power generation featuring centralized distribution and efficient use of resources.
When a camp or operating base is first set up, Force Provider packages, Project Manager-Force Sustainment Systems, provide all life support and other structures needed by the unit. Power is generated by tactical quiet generators, or TQGs. As the footprint expands, commercial generators purchased locally or provided by contractors are often added to augment the existing point generation. Often this results in more power being produced than is actually needed. Generators are run constantly and consume fuel at a constant rate regardless of power demands that may fluctuate during the day. Running generators at a low load results in "wet stacking," which decreases efficiency, increases pollution and reduces the time between maintenance actions and useful life of the equipment.
The RFAST-C team and PM-MEP installed a one-megawatt microgrid at Camp Sabalu-Harrison that can replace up to 20 60-watt TQGs that had been collectively producing more than 1,300 kilowatts of power to meet a demand of less than 400 kilowatts. The microgrid can be configured through distribution networks to provide power to 66 structures, and has the advantage of being able to match power generation with demand as opposed to running stand-alone generators 24 hours a day.
"The microgrid balances supply and demand," said Lt. Col. Alan C. Samuels, RFAST-C director, 401st AFSB. "The microgrid includes a computer-controlled system that senses demand and provides centralized distribution instead of point generation."
"The Intelligent Micro Grid provides 100 percent power to the end user," said Joe Barniak, a contractor with PM-MEP, who keeps the microgrid running and collects daily system data. "It delivers what's needed at the time they need it without having to take a generator off-line for maintenance."
The four large generators in the microgrid system are turned on and off automatically by the system as peaks and valleys in power demand occur throughout the day according to Barniak.
Barniak said the microgrid captures fuel usage and fuel efficiency and generates load profiles. The microgrid generators are rotated automatically by the system's computer to balance the number of hours on all engines.
"It's nice to see technology get out of the RDECs [research, engineering and development centers] and put to use," said Michael J. Zalewski, RFAST-C mechanical engineer who focuses on power management.
Force protection and logistics also enter into the picture according to Samuels and Zalewski. Samuels said each set of stand-alone generators that are scattered throughout the camp requires a fuel blivet that must be refilled on a regular basis while in the case of the microgrid fuel is delivered to one central point. This localization of fuel points and reduces the number of sites that fuel trucks must service throughout the camp, many times on a daily basis.
"Logistics issues arise from having to bring fuel forward by convoy or air drops," Zalewski noted. He also added that there are other technologies that can be employed by expeditionary units to reduce dependence on fuel-powered generators and thereby reducing the number of fuel resupplies requried.
Samuels said looking at demand issues is another step that can be taken to increase energy efficiency and reduce costs for power generation. Suggestions include using solar shades to reduce the thermal loading on tents, tent insulation to reduce the thermal losses to the outside environment and improved environmental control units that have been developed by PM-MEP.
So, back to the initial question of how not to heat and cool the desert -- there are a number of answers, but given the right set of conditions and planning, a microgrid provides reliable power matched to demand loads and peak demand times at a lower cost per kilowatt hour with reduced wear and tear on generators while achieving energy efficiency and improving force protection.