TABLE 7-1 Science and Technology Objectives for the Near Term, Mid-Term, and Far Term, in Three Power Regimes

Power Regime

Near Term (3 to 5 years)

Mid-Term (5 to 10 years)

Far Term (beyond 10 years)

20 W average power

Develop batteries for the 24-hr mission with specific energies >300 Wh/kg.

Develop smart hybrid systems with high-energy and high-power batteries and/or electrochemical capacitors.

Develop generic modeling capabilities.

Develop efficient balance-of-plant components for small fuel cell systems.

Develop small fuel processors for logistics fuel, methanol, ammonia, and other viable fuels.

Develop and field-test direct methanol fuel cell (DMFC) hybrid systems.

Develop and field-test proton exchange membrane/hydrogen (PEM/H2) systems.

Conduct battlefield-relevant safety testing of alternatives (H2, MeOH, ammonia, JP-8, and Li batteries).

Develop rapid start-up, compact solid oxide fuel cell (SOFC) systems operating on low-sulfur logistics fuel or surrogates.

Develop complete small internal combustion and Stirling engine systems with low signatures operating on JP-8 or diesel fuels.

Develop high-specific-energy, air-breathing battery system hybrids.

Develop microelectromechanical system components for power technologies.

Develop SOFC systems that operate directly on high-sulfur and polyaromatic fuels.

100 W average power

Develop smart hybrid systems with small engines and fuel cells.

Develop portable fuel processors for logistics fuel.

Evaluate DMFC and PEM systems for various specific missions.

Develop small engines. Validate performance scaling laws. Assess reliability, failure modes.

Develop SOFCs.

Develop high-specific-energy, air-breathing batteries.

1 to 5 kW average power

Develop lightweight, efficient, 1-to 5-kW engines that operate on logistics fuel.

Develop lightweight logistics fuel reformers.

Integrate logistics fuel reformers with lightweight PEM fuel cells.

Develop high-capacity SOFCs and integrate them with logistics fuel reformers.

KEY: Relative risk: Low, ; Medium, ; High, .

NOTES: MeOH, methanol; JP-8, jet propellant 8; Li, lithium.

Recommendation 6b: The Army should develop smart hybrid systems capable of air-independent operation and the 50-W peak load. These hybrid systems must be developed with the aid of duty-cycle analysis and modeling. Key to this is an evaluation of the limits of battery-battery hybrid system performance as well as methods for packaging or sealing air-breathing hybrid systems.

Recommendation 6c: If the Army determines that a nonstandard fuel source is acceptable for battlefield use by dismounted soldiers (see Recommendation 2 above), it should develop PEM and SOFCs as complete systems with the hydrogen storage or generation subsystem yielding at least 6 percent by weight hydrogen, including all components. In this context, the Army should investigate

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