In response to a Marine Corps requirement from Iraq for an expeditionary renewable power system, the Office of Naval Research (ONR) Advanced Power Generation Future Naval Capabilities program has introduced technology designed to harness some of the sunlight that beats down upon U.S. Marines operating in the Arabian Desert. Fueled by the sun, the Ground Renewable Expeditionary ENergy System (GREENS) is a portable, 300W, photovoltaic/battery system that provides continuous power to marines in the field.
The GREENS system consists of two parts. The first is a hybrid photovoltaic/battery system comprising stackable 1600W solar arrays and rechargeable batteries that combine to provide 300W of continuous electricity. It can be rapidly deployed and is HMMWV (High Mobility Multipurpose Wheeled Vehicle - or Humvee) transportable. The second part is a tool kit that allows a marine to enter an expected mission profile into the GREENS computer that will indicate which components of the GREENS system to pull out and take with them in order to provide their renewable power needs.
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GREENS will provide AC and DC power needs to charge typical communications, targeting, and computing devices. It is expected that by reducing the logistical supply chain for fuel typically needed to generate electricity to power such devices GREENS, and other projects like it, will not only help cut fuel use and costs, but also reduce the associated threats to vehicle resupply convoys in Afghanistan and Iraq.
“It’s vitally important to have power in the battlefield especially these days in an irregular warfare environment,” said Marine Col. Thomas Williams, a senior officer at ONR. “There’s a high demand for computing devices, targeting systems and communications devices in the field. Small tactical marine units are widely dispersed, and they require power and resupply.”
The Naval Surface Warfare Center, Carderock Division (NSWCCD), developed and tested the GREENS prototype. “Providing reliable AC and DC power to remote outposts is what GREENS is all about,” said Eric Shields, a mechanical engineer for the Battery Technology Group at NSWCCD. “Marines will not have to rely on fuel resupplies as much for generators to ensure their radio equipment and batteries have power.”
Approval for the GREENS project was expedited through the ONR Future Naval Capability process and technical execution took less than six months, resulting in tests of the first unit in July 2009. The entire project, from concept to transition, took just over a year, culminating in a contract solicitation announcement to industry to produce and field GREENS for the Marine Corps.
The GREENS system has undergone continuous power testing at Naval Air Warfare Center, China Lake, Calif., where ambient temperatures exceeded 116°F (46°C). Even under the extreme temperatures, the system provided 85 percent of the rated energy, which exceeded performance expectations, prompting the system's rapid development.