SCHOFIELD BARRACKS, Hawaii--Soldiers from the 25th Infantry Division put the Army's ZH2 fuel-cell electric vehicle through the rigors of operating in jungle terrain during a training exercise here in late January.Soldiers evaluated the Chevrolet Colorado ZH2's operational effectiveness during multiple reconnaissance missions as a notional friendly "blue" force (BLUFOR) and "opposition" force (OPFOR) vehicle asset. They provided feedback on its fuel-cell technology and the capabilities it offers.The U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) leveraged General Motors' fuel-cell and off-road vehicle technology investments and commercial off-the-shelf products to develop the ZH2 demonstrator. TARDEC has been collecting data and Soldier feedback on the ZH2's capabilities for more than a year as part of the Army's effort to bring advanced vehicle systems, technology and critical capabilities to the warfighter quickly. Previous ZH2 evaluations involved Soldiers at the squad and platoon levels, while this latest exercise involved an entire battalion-sized element."The ZH2 is more than just a hybridized vehicle. It's really a leap ahead as we look at solutions we're trying to get on the battlefield particularly applicable to reconnaissance and security organizations," said Lt. Col. Tim Peterman, 2nd Squadron Commander, 14th Cavalry Regiment.The ZH2, fitted with a hydrogen fuel cell and electric drive, has a stealthy drive system which produces a very low smoke, noise, odor and thermal signature. This allows Soldiers to conduct silent watch and silent mobility missions on the battlefield. "I think the technology is very useful, and implementation of it could make a positive impact to the cavalry squadron, enabling us to be on the move silently, find the enemy, and kill the enemy undetectable at close range," Capt. Quinn Heydt, 2nd Squadron assistant operations officer.To start the training exercise, the ZH2, which generates 25 kilowatts (kW) of continuous power or 50 kW of peak power when not in motion, was used to export power to the entire squadron Tactical Operations Center (TOC). The ZH2 is capable of exporting both 120- and 240-volt AC power for off-board use."The ZH2 provides an alternative power source other than generators, which are very loud and at times difficult to maintain and move based on the operating environment," Heydt said."The ability to power the Main Command Post with a silent energy source facilitates noise discipline, making it more difficult for us to be detected and also enables us to maintain a lower signature moving across the battlefield," he said.The Army has leveraged more than $3 billion in GM research and development spent on fuel cell technologies over the last several decades."GM has been a terrific partner with the ZH2 program," said Brian Butrico, program manager and chief engineer for the TARDEC ZH2 hydrogen fuel cell electric vehicle program. "We've leveraged their existing designs and rapid prototyping capabilities, enabling us to collect valuable data from testing the military utility and technology readiness of hydrogen fuel-cell propulsion in our unique environments and use cases."While electricity drives the ZH2 vehicle, the electricity doesn't come from storage batteries used in today's electric cars. The ZH2 generates electricity from highly compressed hydrogen stored in the vehicle combined with oxygen from the atmosphere through an electrochemical reaction.Existing fuels such as gasoline, propane, JP8 (the Army's main petroleum fuel source) and natural gas can also be used to produce hydrogen. TARDEC and other Department of Defense entities are researching and comparing the costs and benefits for each energy source to determine which is most effective and efficient for various areas of operation within the continental U.S. and abroad."With the ZH2 demonstrator we were certainly able to validate the durability and reliability of the fuel cell. The fuel cell itself has been extraordinarily reliable," Butrico said."We've been able to show with an operations tempo and a mission profile that includes a lot of idle time that the efficiency of fuel cells far exceeds any of the conventional vehicles that we were comparing it to such as HMMWV, MRZR, or Dagor vehicles," he said. The next step for the program involves investigating different applications for hydrogen fuel-cell technology for stationary generators and for existing vehicles such as those used for special operations and for medium to heavy tactical use. "In the future, I believe the hydrogen fuel cell could be implemented into a larger scale system, the Stryker, for example, or other heavy combat vehicles, and make them more stealthy, more silent, and more capable than any other fuel vehicles we have today," said 2nd Lt. Justin Jung, also from 2nd Squadron. The Army is currently conducting more extensive modeling and simulation for the logistics and supportability of hydrogen, Butrico said. "How do we produce, store, transport, and distribute hydrogen on the battlefield?" he said. "What are the cost implications of hydrogen technology in various applications and phases of major combat operations?"The ZH2 has undergone previous Soldier evaluations in real-world field conditions at Fort Bragg, North Carolina, and Fort Carson, Colorado, where Soldiers gave high marks to the ZH2's off-road maneuverability to negotiate rough and steep terrain and its ability to produce high torque at low speeds. Another key advantage they cited was the ability of the vehicle's hydrogen fuel cell to produce two gallons per hour of potable water.Going forward, Jung believes research labs should focus on producing portable hydrogen fuel cells."In future military operations, having fuel cells small enough for Soldiers to carry in the field that can be used to recharge batteries used for night vision goggle systems, thermal cameras, crew systems, or any UAV assets would be amazing," he said.