The use of renewable energy sources such as wind and solar power has expanded quickly in recent years worldwide, but these sources struggle to meet the fluctuating demands necessary to maintain stability in the power grid. Developing energy storage technologies, such as batteries, so that demand can be met whenever needed would represent a major breakthrough in electricity generation. The challenge is to find the optimal way to integrate these storage technologies into existing infrastructure and plan for the future.

Pacific Northwest National Laboratory has developed two optimization tools that can identify the proper size and use of energy storage systems, easing the path to integration. These tools can be used by energy planners, public utilities, and businesses to determine the cost effectiveness of various energy storage approaches, before attempting to incorporate new technologies into their systems. These tools serve the energy storage market, which is expected to grow rapidly.

Battery Storage Evaluation Tool

The Battery Storage Evaluation Tool is a computer model that simulates the use of an energy storage system to meet multiple objectives. An energy storage device can be charged and discharged in different ways over time. The Battery Storage Evaluation Tool can determine how to control the battery in an optimal manner such that total benefits are maximized.

The tool simulates one year of battery storage operations to evaluate the benefits to the power grid, including energy arbitrage, balancing service, capacity value, distribution system equipment deferral, and outage mitigation. The evaluation tool automatically uses input data to repeatedly formulate and solve the optimization problem at each hour of the evaluation period, and to simulate the actual power exchange on a minute-by-minute basis. The input data includes battery parameters, energy and balancing prices, balancing signals, power requirements from capacity and distribution deferral services, and outage information. The simulation can be run for different locations and differently bundled services, with any of 50 balancing price scenarios. The tool monetizes the annual value obtained for each service (e.g., capacity, distribution deferral) and identifies the number of hours for which the energy storage system is used to provide that service. The results identify the best way to use an energy storage system in the current infrastructure and can be used for future configurations, saving time and money and ensuring efficient and effective power system operations.

Optimal Sizing Tool for Battery Storage in Grid Applications  

The Optimal Sizing Tool for Battery Storage in Grid Applications looks at energy storage systems on the consumer side. It determines the benefits of placing a battery storage system behind-the-meter, that is, on the consumer’s property, rather than as part of the electric grid/utility. Such placement is gaining popularity among businesses as a cost-effective solution to reduce energy and demand charges.

The tool addresses the two most fundamental problems in behind-the-meter energy storage systems for a given building locale, based on its historic energy consumption, and utility rate: 1) what are the economic benefits of a storage system, and 2) what is the most economic energy and power size for the system. The tool analyzes trade-offs between benefits and costs so as to optimize battery size. The results can guide the purchase and use of behind-the-meter energy storage systems for businesses.