Many U.S. Army systems, such as ground vehicles and fully equipped soldiers, are comprised of multiple subcomponents which each typically perform unique functions. Combining these functions into single, multifunctional components could reduce mass and improve overall system efficiency. In particular, creating structural materials that also provide power generating or energy storing capacity could provide significant weight savings over a range of platforms. In this study, structural composite batteries, fuel cells, and capacitors are proposed. To ensure performance benefits, these multifunctional composites are designed so that the materials involved in power and energy processes are also load bearing, rather than simply packaged within monofunctional structural materials. Fabrication and design details for these multifunctional systems, as well as structural and power/energy performance results, are reported. Critical material properties and fabrication considerations are highlighted, and important technical challenges are identified.