Towards a Net Zero Building Cluster Energy Systems Analysis for a Brigade Combat Team Complex

The Army is required by law (Energy Policy Act of 2005 [EPACT] 2005, U.S. Energy Independence and Security Act of 2007 [EISA] 2007) to eliminate fossil fuel use in new and renovated facilities by 2030 and to reduce overall facility energy usage by 30% by 2015. Army policy is to achieve 25 net zero energy installations by 2025 and to achieve net zero energy (NZE) status for all installations by 2058. Achieving NZE will only be possible if an optimum mix of demand reduction and renewable sources are put in place at a community (installation) or building cluster scale. The Army runs what are essentially small campuses, or clusters of buildings on its installations. The Department of Energy (DOE) is focused on the national grid scale or on individual buildings, while the commercial focus is on retrofits to individual buildings There is a lack of tools and case studies that address dynamics of energy systems at the community scale. The Army’s future building energy requirements are a mixture of ultra-low and high energy intensity facilities. Achieving net zero energy economically in these clusters of buildings will require a seamless blend of energy conservation in individual buildings, combined with building systems automation, utility management and control, and power delivery systems with the capability to integrate onsite power generation (including from renewable energy sources) and energy storage. When buildings are handled individually each building is optimized for energy efficiency to the economic energy efficiency optimum and then renewables are added until the building is net zero. This process works for buildings with a low energy intensity process for its mission, such as barracks and administrative buildings. When the mission of the building requires high energy intensity such as in a dining facility, data center, etc., this optimization process either will not end up with a net zero energy building, or large amounts of renewables will be added resulting in the overall technical solution that is not cost effective. But when buildings are clustered together, after each building is designed to its economic energy efficient option, the building cluster is also energy optimized taking advantages of the diversification between energy intensities, scheduling, and waste energy streams utilization. The optimized cluster will minimize the amount of renewables needed to make the building cluster net zero. This paper describes this process and demonstrates it using as an example a cluster of buildings a Brigade Combat Team Complex at Fort Bliss, TX.