In February 2020, the personnel at Fort Hunter Liggett (FHL), California, got to experience firsthand a demonstration of a microgrid similar to what is being installed at the AR-funded Installation. Thanks to a “Teaching Trailer” developed by Schweitzer Engineering Labs (SEL), Inc., those in attendance learned how SEL’s microgrid Supervisory Control and Data Acquisition (SCADA) systems work, how safety features are incorporated, and how the system will function once fully implemented on post. “It was a good way to bring some garrison visibility to the impending microgrid project,” explained Jarrod Ross, the contracted Resource Efficiency Manager (REM) for FHL. “Especially for us in the Directorate of Public Works (DPW) who are directly involved in the project, we had an up-close opportunity to review SEL’s system and get a true feel for a portion of the microgrid once fully implemented.” 

What is a Microgrid and How Does It Work? 
A microgrid connects buildings to a centrally-managed power source and creates a local energy grid with control capability. This means the system can disconnect from the main utility-provided “grid” and operate as an island using locally-generated power from the Installation to remain operational in times of disruption. Those local sources of power can include various combinations of batteries, generators and renewable sources. The use of a microgrid directly supports Army Modernization efforts, as well as resilience mandates defined in Army Directive 2020-03 (Installation Energy and Water Resiliency Policy). 

Microgrid Development at FHL 
Currently, the microgrid system at FHL is in the design phase. Ameresco was awarded the $21.60M firm-fixed-price contract for design, construction, commissioning, validation, training and transition of a fully usable and complete microgrid system. Once fully implemented, the system design will enable contingent electric power to FHL when electricity provided by Pacific Gas and Electric (PG&E) is unstable or unavailable. The estimated completion date is May 2021. U.S. Army Corps of Engineers, Sacramento, California, is the contracting office. SEL, who provided the demonstration to the garrison, is a contract partner for Ameresco. 

The project will add 3.75 megawatts of photovoltaic (PV) generation to the existing 3 megawatts of PV already installed, as well as increase the current 1.25 megawatt-hours of battery energy storage system (BESS) by 5 megawatt-hours. The resulting 6.75 megawatts of PV and 6.125 megawatt-hours of BESS will provide mission resilience to FHL’s critical facilities using only green renewable energy. When islanded mode for mission resilience is not necessary, the renewable systems will achieve electric net zero for the Installation and enable FHL to perform peak shaving and future enrollment in a load response program. This will help FHL to reduce grid consumption and cost. 

“The overarching microgrid effort is more than this one project,” added Ross. “At the same time the PV project is going on, there are two other contracts under construction that will integrate the building controls for 45 buildings, as well as repair, refresh or install functional smart metering at 96 facilities on post.” 

Drawing Inspiration: Exploring a Water Microgrid 
In addition to energy, there’s an opportunity to enhance water resiliency at FHL. An aging water distribution system, no redundant feeds and a large distance from the wells to the main cantonment area are all issues that pose challenges. SRD, with the support of the Pacific Northwest National Laboratory, will explore the concept of the first use of a water microgrid to automatically control water production flow and rates and ensure that water main breaks can be isolated and repaired without major disruptions to operations across the Installation. The study will begin this fiscal year with the exploration of a concept of operations, a full understanding of the requirements and preliminary discussions of options. 

The water microgrid effort is running parallel to FHL’s efforts to improve the resiliency of the existing water system. Water improvement initiatives already set in-motion include an awarded FY17 Energy Resilience and Conservation Investment Program project for the installation of a secondary waste water treatment facility to recycle waste water from post and utilize it as process water for evaporative coolers and toilet flushing in larger facilities. “By partnering with PG&E, we hope to explore the potential for a utility energy service contract to install PV generation and BESS at the wells to ensure potable water production in the event of a loss of utility service,” explained Ross. “This will ensure water resiliency in addition to the electrical resiliency gained from the power microgrid and enhance the overall mission resilience for the garrison.” 

“None of this happens efficiently though without the help and support of the Command Staff as well as the DPW and other FHL directorates,” shared Ross. “Energy and water are used by every individual every day and community support is invaluable to the success of these resilience endeavors. It takes a village to raise a microgrid.”