Industry experts and PSE have studied whether the Eastside’s electrical needs could be addressed by using batteries to store energy. Despite the progress made by the energy storage industry in recent years, an updated analysis concluded that battery storage is still not a practical solution to meet the Eastside transmission system capacity deficiency.
An Eastside battery project would:
- Be significantly more expensive than PSE's plan to upgrade transmission lines along the existing corridor. Battery storage would cost approximately $825 million for a short-term solution and $1.4 billion for the complete solution, compared to an estimated $150 million to $300 million for Energize Eastside.
- Require a huge battery farm on a scale that has never been built. To meet Eastside demand, a battery project would be up to 43 times larger than the world’s largest operational project (Tesla’s Hornsdale project in South Australia).
- Exceed the supply of energy storage systems. The commercial and supply-chain viability of an energy storage system for the Eastside area is unclear as it would exceed total U.S. energy storage deployments in 2017 by approximately 6-13 times.
Battery storage was studied and analyzed in:
- Strategen's Eastside System Energy Storage Alternatives Assessment Report Update, September 2018
- Quanta and PSE's Supplemental Solutions Report in Section 4.3
- Strategen's Eastside System Energy Storage Alternatives Screen Study, 2015
- The Cities' Phase 1 and Phase 2 Environmental Impact Statements under Alternative 2
While battery storage isn’t a practical option for the Eastside’s needs, PSE is exploring the viability of the technology on a small scale.