---
title: "ESS adds 8.5 GWh of sodium-ion to its battery storage portfolio"
type: "News"
locale: "en"
url: "https://longbridge.com/en/news/285453338.md"
description: "ESS is expanding its battery storage portfolio by adding 8.5 GWh of sodium-ion battery cells and modules through a partnership with Alsym Energy. This move marks ESS's entry into the short- and medium-duration battery storage market, traditionally dominated by lithium-ion technology. Sodium-ion batteries are considered a safer alternative, being non-flammable and reducing risks associated with thermal runaway, which are common in lithium-ion systems."
datetime: "2026-05-06T23:15:37.000Z"
locales:
  - [zh-CN](https://longbridge.com/zh-CN/news/285453338.md)
  - [en](https://longbridge.com/en/news/285453338.md)
  - [zh-HK](https://longbridge.com/zh-HK/news/285453338.md)
---

# ESS adds 8.5 GWh of sodium-ion to its battery storage portfolio

Image: ESS

ESS is moving beyond its long-duration energy storage roots into the crowded short- and medium-duration battery storage market – but not with lithium.

The Oregon-based company said it signed a letter of intent with Malden, Massachusetts-based Alsym Energy to add 8.5 gigawatt-hours (GWh) of sodium-ion battery cells and modules to its portfolio.

The move pushes ESS into short- and medium-duration battery storage – a segment where lithium-ion has long been the default – while building out a broader portfolio alongside its existing iron flow systems.

### Why sodium-ion

Sodium-ion batteries are getting attention as a safer alternative to lithium-based chemistries. ESS says the technology it’s bringing in from Alsym is non-flammable and avoids the thermal runaway risks that have been a concern with lithium-ion systems.

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