The City of Issaquah, Washington, is advancing plans for a solar-plus-storage microgrid at Pickering Barn, a historic community facility designated as a resilience hub to support residents during power outages and natural disasters.

The project includes a planned 60-kWh battery energy storage system (BESS) that will be integrated with an existing 64.9-kW DC solar photovoltaic array. Emerald Battery Labs, a Seattle-based sodium-ion battery manufacturer, will work with the city on the battery system's development and deployment.

The project is supported in part by a $671,000 grant from TransAlta Centralia Generation LLC.

Pickering Barn is part of Issaquah's Resilience Hub Initiative, which identifies public facilities that can provide essential services and community support during emergencies. The facility is intended to serve as a warming and cooling center and provide other emergency resources when the electric grid is unavailable.

The city's Solar + Storage Microgrid Feasibility Study identified Pickering Barn as a priority location for a community resilience microgrid. Installation of the solar array, completed earlier this year, represented the first phase of the project. Battery storage is the next step, allowing the facility to disconnect, or island, from the grid and use stored solar energy to support critical loads during outages.

The planned system will use sodium-ion battery chemistry, an alternative to the lithium-ion technology commonly used in stationary energy storage applications. Emerald will focus on battery integration, energy management, battery management system communications and system-level safety validation.

The company also plans to pursue UL 9540, UL 9540A and UL 1973 certifications for the battery energy storage system and support the city through permitting and procurement.

The Pickering Barn project is part of a broader effort by Issaquah to improve the facility's energy performance while preserving its role as a community gathering place. More than 110 years old, the barn hosts a weekly farmers market from May through October and welcomed more than 37,000 visitors in 2025, including attendees at 264 events.

The city installed heat pumps at the facility in 2025 and added the solar array in 2026. Together with the planned battery system, these improvements are intended to reduce energy costs, increase the use of renewable energy and provide a practical example of how public buildings can support community resilience.

Issaquah received LEED Gold certification from the U.S. Green Building Council in 2023, becoming the first city in Washington state to achieve the designation.

The Pickering Barn project illustrates how municipalities can build on existing solar installations with battery storage to extend the role of public facilities beyond their everyday functions and provide greater continuity of services during grid disruptions.