By Col. John Handy, M.SAME, USA (Ret.)

Defense Distribution Depot San Joaquin, Calif., is responsible for receiving, storing, and shipping materials in support of the Armed Forces around the clock and across the world. Founded in 1942 as part of the U.S. Army’s quartermaster system, the depot has supported every major war and many contingency operations over the past seven decades, starting with World War II and continuing through current operations in Afghanistan and Iraq.

The installation is the center of readiness for the Department of Defense’s western region. While all military missions are critical on some level, any interruption in San Joaquin’s communications, data, or electrical infrastructure creates a ripple effect that can jeopardize logistical support. Such a problem significantly impacts missions and creates risks for servicemembers in the field. Ensuring a constant and resilient power supply for the depot is imperative.


In 2018, Defense Distribution Depot San Joaquin began to look at the replacement of electrical transformers as part of a preventative maintenance program, starting with the equipment nearing the end of its useful service life. Electrical transformers were targeted for several reasons. First, they are in the critical path of most power distribution topologies, and most are single points of failure. Second, unlike uninterruptible power supplies and diesel generators, transformers are continuous duty devices. Third, they tend to fail without warning as they near the end of their service life. Finally, when transformers do fail, they often do so in a costly fashion. In addition to the expenses associated with mission interruption, they create losses due to fire and smoke damage and subsequent repairs.

Transformers are at the heart of net zero and other energy efficiency targets. These types of projects are funded by the measurable cost savings over time, which often outweigh the price of equipment, materials, and installation. They have short paybacks and savings-to-investment ratios well above 1.0. As the cost per kilowatt-hour of electricity gets higher, transformer improvements become easier to justify; conversely, their justification becomes more challenging the lower the rate goes. This is a particular issue for large installations that have negotiated a favorable energy rate with the local utility.

Such was the case at San Joaquin. Located in a state well-known for its high cost of living and even higher utility rates, the installation pays a favorable negotiated cost for kilowatt-hour. The Defense Logistics Agency first looked at being able to finance the replacement of the electrical transformers at the depot under a performance contract. Even using transformers that exceeded Department of Energy guidelines; however, there was still a gap between the efficiency savings and the cost of the project. The 100 transformers on the depot had to be upgraded. The challenge was finding the right way to justify the funding needed. It was clear that energy efficiency alone would not be the measure for cost justification.



Sometimes, energy savings alone are not enough to justify a distribution system hardening project. In addition to efficiency, consider energy resiliency as a link in the mission critical chain.

According to Technical Report 1216, military installations should first consider improving the reliability of their existing electrical distribution system. Instead of project justification depending on efficiency, consider resiliency. Complete a Resilience Risk Assessment to evaluate age-dependent vulnerability concerning the mission.

Low-voltage (LV) transformers are a key component to an installation’s electric infrastructure, but they can fail without warning, and there are no immediate solutions in the event of failure. Unplanned repairs include expensive back-up power, fuel, air pollution permits, and poor power quality.

The Department of Energy has determined the mean useful life of LV transformers to be 32 years, with a standard deviation of six years. Therefore, transformers installed prior to 1988 should be considered for replacement. Transformer upgrades can be funded using recurring maintenance and minor repair guidelines within DOD’s SRM program.

Justification would come instead from within the pages of the recently published Department of Defense Annual Energy Management and Resiliency Report, which pointed out that emergency power generation is ineffective if the distribution system is unable to convey that power. It also stated that system upgrades such as switches, power lines, and transformers may be sought in order to pursue the overall goal of resiliency for mission-essential operations.

In as much as San Joaquin’s operations are mission essential, the depot concluded that DOD’s new energy resilience requirements would provide the needed justification to support the project. A transformer upgrade would balance the requirements for flexibility, reliability, and resilience on one hand while acknowledging the resource constraints on the other. The upgrade would also keep a clear focus not only on energy efficiency, but mission effectiveness. In this way, it could be approached with the goal of achieving an optimal balance between greater efficiency and greater resilience. Not only were the transformers the most efficient at the typical loading, their 32-year performance warranty, even if fully loaded, assured the depot of many years of reliable performance.

For the project to become a reality, however, there had to be support from an appropriations standpoint, which ultimately came from the installation’s Sustainment, Restoration, and Modernization (SRM) budget process.

The Defense Logistics Agency’s SRM account plans, budgets, and executes modernization projects for DOD. The program focuses on recurring maintenance and minor repairs that are required to improve the resilience of military installations. Following the program’s guidelines, San Joaquin completed the specified planning study program and gained approval through SRM rather than traditional capital budgets. The scope and size of the transformer replacement project was large enough to support the cost of project management, yet small enough to source funds through operational appropriations methods.


By shifting the focus of the project from efficiency to resiliency, and from capital appropriation to SRM, Defense Distribution Depot San Joaquin was able to take important measures to harden its site. As a resilience project, approval and execution of the transformer retrofit took place in less than a year.

Now, instead of continuing to rely on wishful thinking or reactive repairs, the installation has taken proactive steps toward ensuring energy availability to support its task-critical missions and training programs across the globe.

Col. John Handy, M.SAME, USA (Ret.), is Regional Sales & Business Development Manager, U.S. Western Region, Powersmiths International Corp.;

[This article first published in the March-April 2021 issue of The Military Engineer.]