A new mobile solar power prototype that reduces expeditionary energy supply needs could help the US Marine Corps (USMC) to increase the effectiveness of forward-deployed forces and to decrease vulnerability. The military must reduce both fuel and battery resupply to increase combat-effectiveness and decrease vulnerability. Photovoltaic cells are the only renewable energy source that can meet this challenge. “One of the most significant challenges currently facing the Marine Corps is the need to supply sufficient electricity to individual Marines in forward-operating bases,” said Robert Walters, head of the National Research Laboratory’s Solid State Devices Branch. “Mobile photovoltaics are a technology that can address these needs by leveraging emerging flexible, high-efficiency photovoltaic technology.” The mobile solar power photovoltaic prototype, fitted to a standard USMC-issue backpack, includes a 10.5-in. x 15.5-in. solar panel that can generate more than 11 W under 1-sun air mass of 1.5 illumination. (Image: US Naval Research Laboratory) Now researchers at the NRL’s Electronic Science and Technology Div. are working to increase operational energy efficiency on the battlefield through the combination of on-installation alternative energy production and energy demand reduction. The USMC Expeditionary Energy Strategy is projected to reduce fuel consumed, per Marine, per day, by 50 percent and reduce total weight of batteries carried by nearly 200,000 lb. In collaboration with MicroLink Devices, Design Intelligence Inc. and the USMC Expeditionary Energy Office, scientists at the NRL developed and prototyped a new photovoltaic system to meet the unique needs of USMC Expeditionary Power for robust, high-efficiency solar panels suitable for adaptation to rechargeable batteries in the field. The mobile solar power system consists of an array of single-junction solar cells with a power conditioning circuit that maximizes array power production and charges a standard military-issue, high-capacity rechargeable lithium ion battery. Flexible solar cells with light-to-electricity conversion efficiency as high as 30 percent were demonstrated in multicell panels. Although field tests are still in progress, initial modeling, simulation and experimentation of the 150-sq-in. deployed array produced more than 11 W per 1-sun air mass 1.5 illumination, showing considerable promise for future production. For more information, visit: www.nrl.navy.mil