CASE STUDY

Evaluated Storage for Transmission Reliability for Puget Sound Energy

Opportunity
Puget Sound Energy (PSE), a fully integrated utility serving 1.1 million customers, contracted Strategen to evaluate the cost and feasibility of using energy storage as a reliability and T&D upgrade deferral asset in Central King County (PSE’s Eastside System).

Strategen found that while energy storage paired with other non-wires resources proved to be a solution with benefits exceeding costs, the existing Eastside transmission system didn’t have sufficient capacity for a solution to meet PSE’s operating standards. Therefore, Strategen found that energy storage was not a viable transmission deferral option for the Eastside need.

Approach
Strategen’s research aimed to understand the cost, timing and feasibility of adding energy storage to Puget Sound Energy’s system. Strategen’s assessment included the following:

• An overview of the current state of energy storage

• An assessment of the feasibility of storage paired with other non-wires options to meet Eastside’s reliability need through 2021

• Scenario modeling: Strategen developed a baseline energy storage configuration for assessment along with two alternative configurations.

• An evaluation of whether energy storage could come online in time to meet PSE’s 2017/2018 deadline

• A detailed analysis of the cost-effectiveness of energy storage as a grid resource for PSE

Results
Strategen research determined that energy storage was not a viable transmission deferral option to meet the Eastside need, although energy storage in general is promising as a cost-effective solution to meet other Puget Sound Energy system needs.