Behind the largest battery storage system in the US

Plans for the largest battery-based storage system in the US were announced last week with storage firm AES Energy Storage set to build 37.5MW across two arrays for the utility San Diego Gas and Electric (SDG&E) in California. Energy Storage News caught up with Brian Perusse, vice president of AES Energy Storage and Jim Avery, chief development officer of SDG&E to get an insight into AES’s Advancion storage system technology and the drivers behind the project.

What kind of obligations in SDG&E under to procure energy storage and why?

The California Public Utilities Commission (CPUC) has set targets for investor-owned utilities in California to procure a total of 1,325MW of energy storage capacity in California by 2020. SDG&E’s share is 165MW, and SDG&E may own 50% of its total target. SDG&E currently has approximately 79MW of energy storage on-line or under contract. Of that amount, SDG&E currently owns about 6MW, with the remaining ~73MW owned by third-parties or customers. The recent CPUC approval this month of our contract with AES for 37.5MW brings the amount of energy storage owned by SDG&E to 43.5MW, or 52% of our authorized amount.

What particularly about the Advancion arrays are suitable for this application?

AES’ Advancion energy storage platform is well suited to this type of application as it features a unique system design that enables rapid deployment to meet a short project schedule. Advancion’s infinitely scalable design allows for standard configurations from 100 kW to over 1GW, and from 15 minutes of duration to over four hours without custom reengineering of the platform.

The Advancion system was designed based on the experience gained through more than three million megawatt-hours of delivered service and is equipped to enable long-term system performance by utilizing a unique system architecture and pre-certification program that eliminates technology obsolescence. 

Is plenty of renewable energy already being integrated in the region or is the storage deployment coming in advance of an expected surge in renewable energy installations?

Last year, SDG&E became the first utility in California to supply 33% of the electricity to our customers from renewable resources, five years ahead of the state’s target date of 2020. This achievement makes us one of the cleanest utilities in the US and, we’re not finished – we are on track to exceed 40% renewables in the near future. The rest of our balanced resource mix comes from natural gas; we have no coal in our generation portfolio. California’s updated renewable target is now 50% by 2030.

By charging during off-peak hours, the storage will be positioned to absorb excess wind and solar production, increasing the use of renewable resources and helping to integrate them smoothly and improve grid optimization.

AES claims this will be the largest battery-based energy storage project in operation in the US. What will be the biggest challenges in development stage?

Upon completion, SDG&E’s 30MW Escondido project will be the largest battery-based energy storage installation by energy (MWh) in the US to date. Given Advancion’s unique and scalable design, the development process is very similar to many of the other projects AES has deployed in the US, Chile and Europe.  As with many of the other Advancion deployments, the biggest development challenge usually falls within procuring long lead-time electrical equipment such as transformers, switches, and breakers. 

Can you provide more detail about the batteries from Samsung SDI and power conversion systems from Parker Hannifin?

The Advancion 4 energy storage system features a unique, modular architecture that supports the integration of technology from pre-certified battery and power conversion suppliers like Samsung SDI and Parker Hannifin. Following an initial evaluation period, we work with these industry-leading suppliers to standardize Advancion’s components and communication protocol to ensure interoperability across projects and suppliers. This approach helps to future proof Advancion, as interchangeable supplier components enable replacement and augmentation over the life of the system using newer technologies at the best future price.

What next for Advancion?

The Advancion platform is now available to third party utilities, developers, and commercial and industrial customers seeking to lower system-wide emissions, reduce customer costs, and strengthen grid reliability.

AES is working to deploy its Advancion energy storage system to capitalize on new value plays, including transmission and distribution deferral as well as its ability to facilitate the addition of greater renewable energy to the grid.