Quick, how do you say renewable energy without saying renewable energy? If you guessed “capturing energy from the environment” is somewhere on the table, run right out and buy yourself a cigar. Wind and solar power are touchy subjects for the US military following last year’s sharp U-turn in federal energy policy, but alternative phrasing — like “capturing energy from the environment” — enables would-be defense contractors to pitch renewables-friendly microgrid systems to the Department of Defense without getting embroiled in politically loaded conversations about clean power. New Microgrid Plugs Into “The Environment” Today’s geared-up soldiers, vehicles, and weapons require more mobile power than ever before, and they need power systems that run without the giveaway noise and heat signatures of diesel generators, and don’t require dangerous, expensive fuel transportation convoys. Don’t just take our word for it. The defense startup Chariot Defense has plenty to say on the topic of 21st century warfare and diesel generators: “Drones, sensors, electronic warfare and directed energy systems — all demand more and more power from a battlefield currently reliant on a 19th-century tool: the diesel generator. Breakers trip, noise drowns, exhaust and heat expose, fuel depletes — undermining the missions they support.” Chariot’s core product is Amphora, a compact, storage-enabled microgrid designed for plug-and-play mobility. “Amphora takes the energy already on the battlefield and puts it under optimized software control, so units run their drones, their EW [Electronic Warfare] kit, and their compute from one system seamlessly,” Chariot explains. The system is a resource-agnostic power optimization tool. When Chariot refers to “the battlefield,” they include conventional generators, idling vehicles, and any other resources at hand. Solar power is also in play, though Chariot does not outright say so. The Death Of Diesel If and when the solar element materializes in the Army’s deployment of Amphora, that would not be a surprise. By the early 2000’s, renewable energy emerged as a means of reducing casualties and expenses related to fuel convoys. With the visibility of turbine towers among the factors limiting the Defense Department’s interest in wind power, solar energy has been the main area of focus. Concurrently, Army analysts have been identifying a whole series of operational shortcomings related to diesel generators. An article published by Military Review (the professional journal of the US Army) in 2022 sums it up: “Universally oversized, these generators suffer from wet stacking (when unburned fuel passes through a generator and accumulates in the exhaust system) due to underloading. “A recent study determined that most U.S. Army generators run at 30 percent of their rated capacity.6 Wet stacking leads to poor fuel economy and increased maintenance requirements.” “Typically, the diesel generators are rated at less than 25 kW, and the microgrids include no energy storage or renewable generation. In their present form, these grids are ill-suited to support the products of the electrification of warfare.” A $7.6 Million Contract For The Military Microgrid Of The Future Chariot Defense launched just two years ago in August of 2024, billing company itself as a pioneer in “next-generation software-defined power distribution for modern warfare,” meaning a system that can harvest energy from a wide variety of resources and synchronize it with receiving systems. The technology caught the attention of the leading venture capital firm Andreessen Horowitz, which spearheaded a $34 million round of Series A funding to bring the Chariot’s total raise of $41 million. With the nest egg in hand, Chariot attracted the interest of PRISM (short for Portable Resilient Integrated Storage Module), a new program in the Defense Innovation Unit of the Defense Department that focuses on storage-supported microgrids. Last week Chariot announced that it won a $7.6 million DIU contract to deploy Amphora to the US Army this fall under the PRISM program. “Distributed forces are increasingly dependent on power-hungry drones, electronic warfare, and edge AI compute networks, but legacy battlefield power solutions still rely on loud, heavy liquid-fuel generators that expose unit positions with their ever-present acoustic and thermal signatures,” Chariot points out. As for capturing energy from the environment, Chariot emphasizes that its power management and storage system “captures energy from tactical generators, idling vehicles, wall sockets at full load, or the environment.” More Batteries For Better Warfare As for why DIU continues to explore renewables-friendly systems under today’s fossil-friendly administration, that’s a good question. Maybe winning wars is the answer? “The United States Department of War’s current approach to battlefield electrical energy across the force is fragmented, lacks a framework to meet current and future battlefield power needs, and is tactically and operationally vulnerable to targetable signatures and strained supply lines in areas of contested logistics,” explained DIU last spring, when it solicited bids for the PRISM contract. The avoidance of heat signature doesn’t necessarily mean renewable energy is on DUI’s radar, but the part about “strained supply lines in areas of contested logistics” does suggest a pivot into local power sources, namely, solar. “To address this problem, the services require a flexible, scalable, easily-portable energy storage and power conversion and distribution system, sized between 1kWh GOTS lightweight systems and heavy applications serviced by current 90kWh GOTS energy storage units,” DIU elaborates, with GOTS referring to existing “government off the shelf” systems. “Without this capability, combat units will either be underpowered and unable to achieve their mission, or be anchored to oversized generators,” DIU adds, throwing even more shade on traditional diesel generators. DIU closed out PRISM submissions in March, but the defense advisory firm Praxis Innovation Group still provides a rundown of the particulars, including: * Power: Will input and output 1 – 15 kilowatts (kW) at various Direct Current (DC) voltages up to 48 Volts (V) and world wide Alternating Current (AC) voltages and frequencies.* Energy Storage: Will utilize 1 – 30 kilowatt-hours (kWh) of scalable, energy storage modules.* Interoperability: Will utilize standard military and/or commercial connectors for inputs and outputs.* Size: Depending on energy storage capacity, compact form factor suitable for manportable transport or in light tactical vehicles.* Weight: At the subsystem level, each component will weigh no more than 160 pounds (lbs).* Architecture: Will employ a modular, open system architecture design to allow upgrades of power electronics and energy storage systems as technology improves.* Signature Management: Minimization of electromagnetic, thermal, audible, and visual signatures is critical. What Is This DIU Of Which You Speak? Coincidentally, DIU is currently celebrating its 11-year anniversary. The office launched in 2015, during the Obama administration, when it became clear that the pace of civilian innovation was running ahead of DoD resources. While the technology focus has shifted somewhat since then, the core motivation is the same. DIU aims to speed up the acquisition timeline while also making the process more accessible to startups and small businesses with promising technologies in hand. “DIU opened its doors 11 years ago this week,” the office noted on August 27. “The mission then was bold: bring cutting-edge commercial tech to the front lines, and do it faster than we ever thought possible.” “DIU cuts procurement timelines to field low-cost, high-lethality and critical operational technology into the hands of our warfighters – fast,” DIU emphasizes. Skipping over the lethality part for now, the focus on operational technology covers a lot of bases including the replacement of traditional diesel generators with something more lightweight, transportable, and relevant to the electro-centric warfare of today. For that matter, DIU is not the only Defense Department office chasing the sun. Last year the agency’s Operational Energy Capability Improvement Fund (OECIF) took a step towards adopting a space-based solar power system under the wing of the startup Aetherflux, and the US Army Corps of Engineers launched a demonstration project for a solar-enabled green hydrogen fuel cell microgrid demonstration project. Photo: The US startup Chariot Defense is pitching a microgrid that replaces hot, noisy, logistically burdened diesel generators with batteries that scavenge energy from the battlefield (cropped, courtesy of Chariot Defense).
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