|Sgt. Nathaniel Taylor, 161st Field Artillery, Kansas Army National Guard, cleans up one of the six Hawker HMMWV batteries that store electricity produced by a solar shade at Camp Lemonnier, Djibouti. Photo by Rich Bartell, U.S. Army Public Affairs.|
Power shade system uses solar energy to produce electricity in desert climates
17 August 2011 — By Rich Bartell, U.S. Army Africa Public Affairs
CAMP LEMONNIER, Djibouti - More than a year ago, a team of Kansas National Guard Soldiers set up a solar shade system here that produces two kilowatts of power. With relatively no maintenance, the system continues to silently and steadily produce eco-friendly electricity from the sun.
Recently, Maj. Tim Franklin, the Uniformed Science Technology Advisor to U.S. Army Africa and Steve Tucker of the U.S. Army Natick Research, Development and Engineering Center traveled to Djibouti to assess the power shade system and train Soldiers on its use.
“The system performed well during the year-long, limited military user assessment. Despite the harsh winds, high temperatures and extremely dusty conditions, the system remains fully operational with only minor de-lamination on three of the 72 panels. It produces virtually maintenance-free power,” Franklin said.
He said the silent, zero-emission and logistic-free power the system produces provides tangible savings.
“The solar shade system produces the same amount of power that would be produced by a gas driven generator using eight gallons of fuel a day, or approximately 2,900 gallons in a year. In remote sites, gas costs about $15 a gallon when you factor in transportation and handling. When properly used in the optimum environment, a system like this has the potential to save the Army as much as $40 thousand dollars a year,” Franklin said.
He said there are many other second and third order positive effects, such as less maintenance to generators and refueling trucks, reduced manpower requirements for mechanics and drivers and decreased power requirements due to the thermal protection the solar shade provides.
“Most importantly, the reduction in fuel convoys equates to a reduction in associated casualties from IEDs [improvised explosive devices] and small-arms fire when used in a hostile environment. That's a metric that you cannot hang a dollar value on," Franklin said.
The system is simple and consists of 72 solar panels located on the top of the 40-by 60-foot surface of the shade. Power is stored in six Hawker HMMWV batteries encased in three metal boxes. It resembles a tent-like awning used at outdoor events and can allow smaller tents to be set-up underneath it.
Tucker, an electrical engineer uses the “bathtub” analogy to describe how the solar shade system works. “Using the solar shade as an alternative energy source is all about understanding of the balance of power,” Tucker said.
“Think of the solar shade as a bathtub filled with water. The water is the energy produced and stored by the shade. It’s usable energy. The solar panels create energy that goes into the battery system, just as the faucet pours water into the bath tub,” Tucker explained.
“This is where the balance of power comes in, where users must ensure the power used doesn’t exceed the amount of power stored,” Tucker said.
“It’s a paradigm shift. It’s a different mindset from having a generator, where you have energy only as long as you have fuel. The biggest challenge is managing the expectations of the user. The system has advantages far above and beyond fossil fuel fired generator systems. Again, there isn’t a logistics tail. It doesn’t require fuel, nor does it require weekly maintenance,” Tucker said.
The power shade is particularly appropriate to power small electric devices such as fans, radios and computers.
“We’ll continue to work with Army units and Combined Joint Task Force-Horn of Africa to refine and validate requirements for remote, silent expeditionary power, especially where logistical resupply is a challenge,” Franklin said.
“This is not a science project. The end-state is to see promising alternative energy technologies such as the solar shade advance to enduring solutions for the Army. That can only be accomplished with validated requirements and a coordinated effort between the warfighters, program managers, TRADOC combat developers, and the RDECOM science and technology office,” Franklin said.
During the two-day training Franklin and Tucker engaged eight Combined Joint Task Force Horn of Africa personnel in the use and assembly of the solar shade. They took the shade down and reassembled it after a complete cleaning and maintenance of the system.
The solar shade has been added to the organization’s property book and is ready for use in any of several CJTF - HOA operational area.