Energy Security Through Distributed Energy Resources: 
Protecting Critical Facilities 

By Petros Siritoglou (Hellenic Navy, NPS ’20 Electrical Engineering Graduate), Giovanna Oriti PhD (Dept. of Electrical Engineering), and Douglas L. Van Bossuyt PhD (Dept. of Systems Engineering)

Energy security is of great strategic importance for facilities where critical loads are present. When the utility grid suddenly malfunctions, the energy security of a facility is threatened, and the use of microgrids with distributed energy resources (DERs) can improve the situation. Backup diesel generators are typically available in critical facilities and are generally turned on to power critical loads when the utility power grid is down. However, diesel generators are not sufficient to ensure the resilience of a critical facility because the diesel fuel supply may not be guaranteed, for instance, for the time during which critical loads must be powered. To further improve the resilience of a critical facility, we propose a back-up microgrid including at least one renewable energy source and energy storage.

In order to aid in implementing backup microgrids at military facilities, our recently published work proposes a design methodology that follows the guidelines in IEEE Standards 1562 and 1013 to size the combination of a renewable energy source, such as a photovoltaic (PV) array, and energy storage to develop a microgrid. The microgrid is explicitly a secondary or redundant microgrid that has the goals of (1) improving the resilience of a critical facility, and (2) boosting energy security to allow for full-time mission support when the utility grid is down and fuel delivery is interrupted.
This novel design method can assist energy managers in the early design stages of back-up microgrids to improve the energy resilience of their facilities, as it is a method based on worst-case analysis rather than an optimization method. Among other features, the design method allows for the designer to verify that the sizing of energy storage is sufficient based on potential PV failures in the context of improving the resilience of a microgrid to a variety of disruptions. Additionally, the design method was implemented on a MATLAB-based experimentally validated software platform featuring a user-friendly interface and less than 1 second processing time. The software could run in manual or automated mode, allowing for use with no knowledge of DER components’ datasheets and performance.

 Several microgrid-design examples are available that demonstrate how the proposed method can be used to achieve the user’s resilience goals with a stand-alone microgrid. Specifically, using the software tool, a facility energy manager can simulate potential disruptions to verify that the design could allow for the microgrid to continue to operate through one or multiple disruptions and recover in an acceptable period of time. Examples include obtained simulations with a physics-based model that can run from the design software’s output GUI. We ran two 24 h laboratory experiments on COTS microgrids to validate the design method and physics-based model.

The design software is fully editable and available to research groups for future optimization. A team of engineers is currently conducting research on optimizing different aspects of back-up microgrid design using this methodology, and is porting the design software to Python in order to better provide resilience to critical facilities. The availability of such a methodology and the open-source tool implementation offers a great advantage towards achieving energy security.