Energy security is a significant strategic priority for the Department of Defense (DOD) from a fiscal, operational, and tactical perspective. The DoD’s Operational Energy Strategy specifically outlines a three-step approach to ensuring a reliable energy supply:1
- Reduce demand
- Expand and secure energy supplies
- Build energy security into the future force
While more efficient buildings, vehicles and processes work to address demand, energy microgrids are helping to ensure access and availability by reducing dependence on external power supplies.
What is a microgrid?
A microgrid is an independent, decentralized power system that allows facilities greater control of their own energy supply, reducing reliance on the external power grid to supply necessary electricity. Microgrids increase energy reliability by protecting against typical power outages caused by downed power lines, grid failure, and human error, as well as more malicious threats to supply such as hacking and potential cyber-attacks.
They also contribute to self-sustainability – a factor that takes on even greater importance in 21st-century military operations. There are some risks associated with microgrids; because they are a finite source of power that are vulnerable to energy fluctuation, and unusual demand may overwhelm the system, putting operations at risk.
Microgrids rely on both energy generation and energy reduction to maximize efficiency and minimize risk. To address the need for supplemental energy generation, fossil fuels and renewable energy sources such as solar, wind, and geo-thermal power are used. Energy reduction strategies not only make microgrids more reliable, they support the DOD’s commitment to meeting and exceeding federal energy legislation and executive orders2.
As the nation’s largest energy user, the Department of Defense is also a major influencer when it comes to improving energy efficiency and embracing renewable energy. In its 2010 Memorandum of Understanding, the DOD acknowledges, “Solving military challenges through innovation has the potential to yield spin-off technologies that benefit the civilian community as well.”2
Each branch of the military has identified major energy initiatives in pursuit of increased efficiency, and the Army has established a goal of 30 installations meeting net-zero energy goals by 2025. A net-zero facility produces as much renewable energy on-site as it uses. Reducing demand is a critical first step to net-zero goals, as it reduces the amount of renewable power that has to be generated.
Reduce lighting use to meet energy-reduction goals
Lighting control – one of the most important opportunities for reducing electricity use – is often overlooked in strategic plans. Lighting is typically a building’s largest electricity consumer, accounting for approximately 38% of total building electricity use3.
Lighting control systems that incorporate automatic control strategies such as digital dimming, occupancy sensing, and daylight sensing will typically deliver lighting electricity savings of 60 percent, effectively reducing total building electricity by 23%3.
- Digital dimming – Spaces are often over-lit. Digital fluorescent dimming ballasts can be used to reduce maximum light levels in a space by 20% or more (a strategy often referred to as high-end trim). Because the human eye readily adapts to slight variations in ambient light, those changes are virtually undetectable to occupants, and typically save 15-20% lighting electricity4.
- Occupancy/vacancy sensing – Occupancy/vacancy sensors work to ensure that lights are not left on when a space is vacant, generally saving an additional 30%5.
- Daylight sensing – In perimeter spaces, daylight sensors can be used to automatically adjust light levels based on the amount of daylight in the space. Daylight harvesting can contribute 20-60% lighting energy savings6, and because lights adjust over a few seconds time, the change is generally transparent to the people in the space.
NASA’s Propellants North Administrative and Maintenance Facility at the Kennedy Space Center is an excellent example of how these simple strategies can be used to effectively reduce electricity demand, and help facilities achieve net-zero energy use.
Microgrids commonly work in concert with grid-based energy sources to provide essential electricity generation during normal, day-to-day operations. During emergency situations, or situations that require the microgrid to supply all essential electricity, lighting controls can be programmed to shed load for maximum system efficiency.
Why are these technologies so critical in military operations?
In military operations, especially in remote locations, relying on microgrids to provide essential power can save lives. Fossil fuels have to be transported in frequent fuel convoys putting military personnel and equipment at significant risk. Minimizing the demand for fossil fuels reduces base vulnerability and limits the risk of dangerous energy fluctuations. Self-generating power also limits defense dollars spent consuming energy.
Microgrids represent a move toward greater energy safety, security, and independence for the military, and ultimately, for everyone served by the increasingly-stressed power grid. Achieving microgrid success is about more than power generation. It is about controlling energy use and reducing energy demand with innovative conversation strategies that save money, time and resources.
About the Author:
Andrew Wakefield is Director of Government Solutions for Lutron Electronics, a U.S. based company that designs and manufacturers more than 16,000 energy-saving products, sold in more than 100 countries throughout the world.
1 Operational Energy Strategy Implementation Plan, Department of Defense. Energy.defense.gov http://energy.defense.gov/Operational_Energy_Strategy_Implementation_Plan.pdf
2 DoD’s Energy Efficiency and Renewable Energy Initiatives (July 2011) Environmental and Energy Study Institute Fact Sheet Online. Retrieved August 7, 2013 http://files.eesi.org/dod_eere_factsheet_072711.pdf
3 Energy Information Administration, 2003 Commercial Buildings Energy Consumption Survey. Building Characteristics Tables, released December 2006. Online. Retrieved from http://www.eia.gov/emeu/cbecs/cbecs2003/detailed_tables_2003/2003set1/2003pdf/a1.pdf
4 Williams A, et al. 2012. Lighting Controls in Commercial Buildings. Leukos. 8(3) pg 161-180.
5 VonNieda B, Maniccia D, & Tweed A. 2000. An analysis of the energy and cost savings potential of occupancy sensors for commercial lighting systems. Proceedings of the Illuminating Engineering Society. Paper #43.
4 Brambley MR, et al. 2005. Advanced sensors and controls for building applications: Market assessment and potential R&D pathways. Pacific Northwest National Laboratory: prepared for U.S. Department of Energy.