Finding the Optimal Solution...

Finding the Optimal Solution for Energy Efficiency and Renewable Energy

ABSTRACT

The Department of Defense (DoD) Installation energy managers face the daunting task of changing the way their Installations produce and consume energy. This paper evaluates the current approach to managing energy at Installations and defines a new option for achieving the goals established by numerous Federal, DoD and Service Mandates.

THE PROBLEM

Military Installations—large, multi-user facilities—require energy for a diverse range of amenities, including hospitals, manufacturing operations, schools, office space, maintenance and storage facilities, troop dormitories and residential housing. Identifying solutions to reduce energy consumption and increase renewable energy production for Installations with hundreds of buildings is a daunting task.

With very limited resources, the energy manager must determine which of the many ideas or proposals they receive from local vendors and contractors will help them achieve their goals, while keeping in mind the best interest of the Federal Government. Although the energy manager does follow an “energy plan” that outlines capital expenditures on energy equipment for several years out, unfortunately, the plan typically focuses on replacing failing equipment rather than reducing energy demand and increasing renewable energy production.

Diversity of locations, climates, energy needs, the mission of the installation and its constituents, existing infrastructure and the availability of various alternative energy inputs make prescribing one solution for every situation difficult. To complicate matters further, there is no historical energy consumption data for the energy consuming equipment at the Installations. In fact, most Installations rely on a single meter to measure the electrical demand aggregated across several hundred buildings. Although the U.S. Army Core of Engineers (USACE) has contracted to install meters at every building, these meters will not provide enough clarity on how energy is actually used. Without this information, decision makers don’t know where to focus available resources or how to evaluate all the possible solutions.

THE SOLUTION

At EET, the approach to this problem focuses on a reduction in energy demand and cost effective renewable energy supply and process modifications that, when combined, can enable Installation energy managers to achieve the many mandates and requirements they face today.

EET developed this process, in part, through our work at Fort Belvoir, VA. The plan we outlined for the Area 300 compound will reduce energy consumption at the Installation by nearly 60% and potentially produce all energy necessary—using only renewable resources—to supply 46 buildings.

The process follows three distinct steps: information gathering (in orange), information processing (in blue) and system optimization (in green). During the last two iterative steps, the process continually moves back and forth between system design and financial return calculations among the alternatives.

The diagram below shows the process flow to provide decision support for a new energy plan.

Information Gathering

As mentioned earlier, most DOD Installations do not have detailed historical information for each piece of on-site, electricity-consuming equipment. In lieu of detailed historical information, EET gathers information regarding the type, size and operating parameters of this equipment. From that information, we estimate the energy consumption. In this step, we also gather important information regarding the uses of the building and equipment. For example, we distinguish between a chiller that cools a data warehouse and a chiller that cools an infrequently used ballroom. Once we complete this “Energy Audit,” we then process the information to draft an optimization plan.

Information Processing

Understanding the energy consumption for each component marks only the beginning of the process. Developing the optimal solution requires an understanding not only of how each component works individually, but also, how each piece of equipment could work with other pieces of equipment, how it could be controlled and what alternatives exist. The information processing step formulates several combinations using a variety of control schemes based on the needs and uses on site. Alternative technology consideration begins here. For example, the efficiency of a chiller that cools the infrequently used ballroom affects energy consumption less than integrating the ballroom reservation schedule with the operating schedule of the chiller would. By contrast, capturing waste heat from the chiller that cools the data center could save more energy than controlling when the chiller switches on or off. When we finish considering alternative configurations, we move to develop financial cash flow and payback analysis of the individual alternatives in the system optimization process.

System Optimization

Many different combinations of technology, process and potential system design could achieve the stated objective. For example, building a solar energy system could provide the energy necessary for the site. However, inefficient, on-site, electricity-consuming equipment or a flawed process of delivering cooling and heating to the buildings would result in a very expensive overall design. The process of system optimization takes into account the best potential solutions, from a process engineering perspective, and compares them using a number of financial metrics, including payback, return and lifecycle cost. The first round of system optimization often reveals some clear winners and losers, however, it is important to go back to the system design process and reconsider alternative combinations based on the first set of financial calculations.

CONCLUSION

Finding the optimal solution of replacing 80% of the energy supply with renewable energy is possible to achieve. Using a detailed process that takes into account current energy needs, the potential to reduce consumption, new technology, alternative supplies and financial comparison can lead to an energy efficient, operationally efficient and capital efficient solution. Achieving the optimal solution will require the active development and consideration of several different combinations of technologies, rather than a reactive consideration of solutions proposed by the local equipment and energy service providers. The solution will not rely on one tactic, but rather, it will include several integrated pieces that, when added together, create the greatest reduction in energy cost for the least amount of capital. This method provides both a long- and short-term road map for achieving the goals along with an estimate of the capital required to get there. Likely, energy managers will lack the funding necessary to accomplish everything at once. However, this approach provides energy managers with a plan that allows them to focus on an integrated, long-term, optimal solution rather than waste money on pieces and parts of a more temporary solution.