SnoPUD Deploys Innovative Energy Storage Program

Background/Why Energy Storage?


Snohomish County PUD has installed the first two battery systems as part of a multi-year program aimed at transforming the marketplace and how utilities manage grid operations. These battery storage systems are the first to be built using the cutting-edge Modular Energy Storage Architecture (MESA). The first two batteries are located at a utility substation near the PUD’s operations center. The installations are designed to improve reliability and the integration of renewable energy sources, which are rapidly growing in the Pacific Northwest.

The PUD recognizes that the electrical grid needs to change to take on more renewable power. MESA’s standards-based energy storage systems and software will play major roles in that change. MESA provides standard interfaces between equipment components such as the power conversion system, batteries and control system. It brings more choices for utilities, reduces projects’ complexity and promises to lower costs. The system offers a non-proprietary and scalable approach to energy storage.

Energy Storage Projects

The program, which forges partnerships with major U.S. and international business partners, includes two large-scale lithium ion batteries, one manufactured by GS Yuasa International Ltd. and supplied by Mitsubishi and a second manufactured by LG Chem. Both lithium ion batteries utilize a Parker Hannifin Power conversion system. In late 2016, the PUD plans to deploy multiple advanced vanadium flow batteries, built by UniEnergy Technologies, at a second PUD substation.

The utility is managing its energy storage projects with an Energy Storage Optimizer (ESO), a software platform that runs in its control center and maximizes the economics of its projects by matching energy assets to the most valuable mix of options on a day-ahead, hour-ahead and real-time basis.


The project was made possible in part by a $7.3 million investment from the Washington State Clean Energy Fund.

The PUD has received an additional $1 million from the Clean Energy Fund for a partnership with the Bonneville Power Administration and the University of Washington to optimize the use of energy storage and demand response. The project will model how these assets may be used to move energy to:

  • Mitigate both technical and economic costs of congestion
  • Improve the reliability and operating costs of BPA’s transmission grid