The U.S. Army is harnessing the elements to help reduce casualties from sniper attacks on forward operating bases. The U.S. Army Research, Development and Engineering Command's research laboratory and aviation missile and communications-electronics RD&E centers - the Army Research Laboratory (ARL), the Aviation and Missile Research, Development and Engineering Center, and the Communications-Electronics Research, Development and Engineering Center (CERDEC) - have integrated and deployed wind and solar harvesting systems to provide continuous energy to company-level, force protection systems used by U.S. Army combat units in theater.

A joint venture by ARL, Aviation and Missile Research, Development and Engineering Center, known as AMRDEC, and industry, the Hostile Fire Detection Sensor – a.k.a. Firefly - is a 360-degree surveillance system that uses acoustics fused with Short Wave Infrared detectors to locate enemy shooters for more accurate return fire. Firefly detects line-of-sight and non-line-of-sight hostile fire and classifies these as small arms, heavy machine gun or rocket/mortar. It calculates geo-location of the shot and provides self-position and heading in a standard cursor-on-target format. The Firefly can be either a mobile or fixed system, attached to a soldier's backpack while on patrol, or mounted at forward operating bases.

The Firefly system was initially deployed to Afghanistan in May 2012 to support a fires detection requirement. However, deployment sites faced challenges in sustaining conventional power delivery to Fireflies along perimeter walls due to enemy attacks when soldiers were above the wall line changing batteries.

"In our attempts to solve the power issue, we discovered that CERDEC had sponsored the development of RENEWS power kits, which offered more complete solutions for charging the power supplies," said William Lawler, an electrical engineer in ARL's Sensor Integration Branch. "They immediately provided us with several kits, which we sent to AMRDEC for integration with Firefly and testing. Once it was determined that this solution satisfactorily extended the power supply, CERDEC provided several solar versions of the kits for deployment."

The Reusing Existing Natural Energy, Wind & Solar system (RENEWS) enables the harvesting and utilization of wind and/or solar power and is intended to produce up to 300 watts of energy field usage in silent, remote operations where the supply of power and fuel resupply is difficult or risky. RENEWS consists of a wind turbine, three 124-watt flexible solar panels, a power conditioner, an AC inverter, and a battery storage/charging unit that contains six BB-2590 rechargeable batteries; it can be hooked into either the solar panels or the wind turbine for continuous charging. The BB-2590 battery, which was developed by CERDEC CP&I, is lighter than the standard BB-390 battery and features better capacity.

"RENEWS offers options; solar was preferred in this case, using the solar panels to charge the six-pack of batteries during the day. We connected a cable from the RENEWS kit to the Firefly, giving them 1.2 KW of continuous energy to run the Firefly system. There still was some maintenance to check the Six-Pack and clean the dirt off the solar panels, but the soldiers are not going up there every day because the solar panels are within the walls, so they're not exposed to enemy fire," said Daniel Berka, an electronics technician in CERDEC's Command, Power & Integration directorate (CP&I).

The integrated solution also provided an opportunity for CERDEC CP&I to gather additional operational feedback to be used in efforts to reduce soldier load and logistical support, said Pedro Passapera, chief for CERDEC CP&I's Experimentation and Simulation Branch.

To date CP&I has deployed 40 complete RENEWS systems and more than 60 solar systems to units.