Ameresco, Inc. announced it has signed a contract with Snohomish County Public Utility District (PUD) to construct a battery energy storage system (BESS) with a 20-year guaranteed capacity of 25 megawatts (MW) and 100 megawatt-hours (MWh). The installation represents the largest standalone battery project to date in the Pacific Northwest. The 25-year tolling agreement keeps Ameresco as the asset owner and Snohomish PUD as the exclusive customer of the project.

The BESS will provide the PUD with enhanced electrical system reliability and flexibility while reducing exposure to energy price volatility, making the project a significant milestone in the advancement of sustainable energy solutions in Washington State. Construction on the energy storage asset is currently expected to begin in late 2024 and be operational in late 2025. It allows Ameresco to provide Snohomish PUD the flexibility to utilize the battery energy storage system for charging and discharging activities under the tolling agreement.

This long-term arrangement underscores both organizations' commitments to driving innovation and sustainability within the region.