Publications

Microgrids are areas that are self-sufficient for power that can controllably disconnect from the incoming utility feed and control generation assets in conjunction with changing load requirements. They are increasingly being touted as a way to improve installations energy resilience because they allow installations to decouple from the larger electric grid if it fails and continue to provide power in the face of growing natural and man-made threats to Marine Corps installations. However, before commanders can put resources toward upgrading infrastructure, they need to identify and understand their vulnerabilities. A key way to do this is by holding exercises designed to simulate grid failures and outages either in a tabletop manner or in realtime. These exercises also help personnel train for disruptions, understand their impact on operations, and identify unknown interdependencies that can be just as important as investing in resilient technology and the physical electric grid. In order for the equipment to work, personnel have to know how to employ it and commands need to understand how outages will affect their installations. These types of exercises are as important as the physical infrastructure or ensuring the energy resilience of Marine Corps installations and the missions that depend on them in the future.

The goal of the study was to develop and demonstrate an energy resilience framework at four DoD installations. This framework, predominantly focused on developing a business case, was established for broader application across the DoD. The methodology involves gathering data from an installation on critical energy load requirements, the energy costs and usage, quantifying the cost and performance of the existing energy resilience solution at the installation, and then conducting an analysis of alternatives to look at new system designs. Improvements in data collection at the installation level, as recommended in this report, will further increase the fidelity of future analysis and the accuracy of the recommendations. And most importantly, increased collaboration between the facility personnel and the mission operators at the installation will encourage holistic solutions that improve both the life cycle costs and the resilience of the installation's energy systems and supporting infrastructure.

In today's interconnected battlefield, our war fighters are increasingly reliant on capabilities at domestic military installations to support critical missions, often in near real time. Many of the domestic installations of the U.S. Department of Defense (DoD) also support everything from sensitive research and development facilities such as microelectronics and biological laboratories to large industrial plants such as shipyards and aviation depots. These facilities depend on the electricity provided by the commercial electric grid. Extended-duration outages on the domestic electric grid will therefore both significantly affect the operational mission of the DoD and bring substantial economic consequences. The changing nature of electricity markets presents new opportunities for the DoD to reduce electricity costs while addressing its energy security needs. Demand response, ancillary service markets, and real-time pricing offer large consumers of electricity such as military installations a significant opportunity to use installation assets during grid-tied operation. Nevertheless, this is an opportunity the DoD can only exploit if it does so in a secure fashion, well protected from cyber threats.

Concern about energy security on domestic Department of Defense installations has led to the possibility of using natural gas-fired electricity generators to provide power in the event of electric grid failures. The natural gas system in the United States is partly dependent on electricity for its ability to deliver natural gas from the well-head to the consumer, but it also uses natural gas from the system itself to fuel some of the drilling rigs, processing units, and pipeline compressors. The vulnerability of the system to a disruption in the national electricity supply network varies depending on the cause and breadth of the disruption and where in the country one is located relative to that disruption, as the interconnected nature of transmission pipelines, the penetration of electric motor-driven compressors and other equipment, and the availability of nearby gas production, import terminals, or storage varies. In general, the gas supply system is reliable for short-term, limited-area disruptions in the electricity supply, and firm delivery contracts for natural gas increase the likelihood of continued operation, but for disruptions that cover large sections of the electric grid encompassing areas from extraction wells to customers and which last longer than available gas in storage or transmission pipeline constraints from elsewhere, contractual force majeure limits will come into play rendering the firm delivery contracts void; operation of gas-fueled power generation systems that are not dual-fuel capable for longer than weeks to a few months (depending on time of year) will be unlikely. Several weather-related outages in recent years have provided limited case studies showing the system's resilience, but no long-term, widespread electricity grid failures have occurred.

Growing concerns about the vulnerability of the electric grid, uncertainty about the cost of oil, and an increase in the deployment of renewable generation on domestic military installations have all led the Department of Defense (DoD) to reconsider its strategy for providing energy security for critical domestic operations. Existing solutions typically use dedicated backup generators to service each critical load. For large installations, this can result in over 50 small generators, each servicing a low voltage feeder to an individual building. The system as a whole is typically not well integrated either internally, with nearby renewable assets, or to the larger external grid. As a result, system performance is not optimized for efficient, reactive, and sustainable operations across the installation in the event of a power outage or in response to periods of high stress on the grid. Recent advances in energy management systems and power electronics provide an opportunity to interconnect multiple sources and loads into an integrated system that can then be optimized for reliability, efficiency, and/or cost. These integrated energy systems, or microgrids, are the focus of this study. The study was performed with the goals of (1) achieving a better understanding of the current microgrid efforts across DoD installations, specifically those that were in place or underway by the end of FY11, (2) categorizing the efforts with a consistent typology based on common, measurable parameters, and (3) performing cost-benefit trades for different microgrid architectures. This report summarizes the results of several months of analysis and provides insight into opportunities for increased energy security, efficiency, and the incorporation of renewable and distributed energy resources into microgrids, as well as the factors that might facilitate or impede implementation.