Bankability of Long Duration Energy Storage (LDES) Manufacturers

Key Takeaways

The author has evaluated the bankability of leading LDES original equipment manufacturers (OEMs) using two criteria: financial performance and field deployment record.

In this issue, ESS emerges top in financial performance among publicly-listed pure play LDES OEMs. The honors go to NGK in the field deployment aspect. These companies demonstrate strong potential for long-term growth and profitability.

LDES Market

As of 31 December 2024, dozens of companies had been founded to commercialize various long duration energy storage (LDES) technologies. These are storage technologies that can deliver 10+ hours of discharge at rated power (as defined by the United States Department of Energy) more cost effectively than the dominant lithium-ion battery technology. The LDES market is fragmented thus highly competitive. To a developer, investor, technology enthusiast or even an OEM, the billion-dollar question is: who will survive the technological valley of death? Consider this article an update towards getting to the answer.

In this April 2025 issue, the author has leveraged two performance metrics namely, financial metrics and field deployment. The competitiveness of a technology is proven in the market thus financial metrics are critical in assessing the market strength and financial health of an LDES OEM. Additionally, the number of operational units under real-world conditions is a strong indicator of product reliability.

Companies to watch

For the financial metrics, the author has selected LDES OEMs based on:

1. Listing (public vs private): the author selected publicly listed companies since public companies are mandated by law to disclose their financial performance.

2. Structure (pure-play vs conglomerate): the author selected pure-play energy storage companies since conglomerates do not tend to specify the financial performances of their energy storage subsidiaries/divisions.

For the field deployment metric, the author has evaluated LDES OEMs irrespective of company type. The criteria used here is:

1. Cumulative installed capacity: must exceed 1 MWh

2. Number of distinct installation sites: must exceed 1

The list of companies in the previous January 2025 issue was as follows:

• CellCube Energy Storage GmbH (“CellCube“)

• Eos Energy Enterprises, Inc. (“Eos“)

• ESS Tech, Inc. (“ESS“)

• Invinity Energy Systems plc (“Invinity”)

• NGK Insulators Limited (“NGK“)

• Dalian Rongke Power Co., Ltd. (“Rongke“)

• Sumitomo Electric Industries, Ltd. (“Sumitomo“)

• VRB Energy, Inc. (“VRB Energy“)

In this April 2025 issue, the list has been updated as follows:

• Additions

  • No additions

• Exclusions

  • No exclusions

As such, the company list in this April 2025 issue contains the following 8 entries: CellCube, Eos, ESS, Invinity, NGK, Rongke Power, Sumitomo Electric and VRB Energy.

Some notable LDES OEMs such as Form Energy have not included herein due to their lack of operational pilot and commercial projects.

Additionally, the following top LDES providers did not meet the author’s deployment threshold detailed above: Antora Energy, Energy Dome, EnerFlow, Energy Vault, Form Energy, Highview Power and Largo.

More on this in the field deployment section herein.

FY 2024 Financial performance

Three of the reviewed manufacturers are publicly listed and two have disclosed their FY 2024 financial performance. The companies’ FY reports are linked in the table below. See further financial details in this LDES Tracker.

Net profit margin = (net income/revenue)*100; a measure of how much profit is generated as a percentage of the revenue.

Eos attributes its year-over-year (YoY) decrease in revenue to reduced production and delivery of Z3 BESS due to the installation of a new 1.25-GWh automated manufacturing line at its factory in Turtle Creek, PA.

Strategy and risk

Key to Eos’s strategy is its ‘Made in America‘ program that enables buyers of its products to qualify for the 10% domestic content bonus under the Investment Tax Credit (ITC) incentives. Regarding risks, Eos notes the recent 25% U.S. tariffs on Canada and Mexico as a business risk as the company sources 15% of parts, products and materials from the two North American countries. Additionally, potential reduction and termination of government subsidies and economic incentives under funding programs such as ITC and Bipartisan Infrastructure Law (BIL) might reduce demand for Eos’s products. Eos also has a few ongoing legal proceedings that the company expects to win but whose outcome is not guaranteed.

A cornerstone of ESS’s current strategy is market expansion through joint ventures, strategic partnerships and licensing arrangements which could yield economies of scale, if successfully implemented. On the risk front, ESS sources parts from China, Canada and Mexico thus its cost of revenue stands to increase due to the recent tariff hike by the U.S. on the 3 countries. Non-tariff related supply chain and logistical issues also pose a challenge to the profitability of the operations of ESS.

Field deployment

The table below displays the deployed capacities of 7 companies across pilot, demonstration and commercial projects. See full project details in this LDES Tracker.

The following notable LDES OEMs were not included in the table above because they did not meet the deployment threshold:

• Antora: 1 operational pilot project rated 5 MWh

• Energy Dome: 1 operational pilot project rated 4 MWh

• Energy Vault: 1 operational commercial gravitational energy storage project rated 100 MWh

• Eos: no publicly available deployment records

• Form Energy: no operational projects

• Highview Power: 1 operational pilot project rated 15 MWh

• Largo: 1 operational commercial project rated 5.5 MWh

The LDES Tracker contains further details of all the projects listed above.

Author’s take

Among the publicly-listed pure LDES OEMs, ESS demonstrates higher financial strength with a net loss margin of -1369.7% YoY. However, Eos’s net income grew faster at -4.7% YoY.

From a deployment viewpoint, NGK has leads with 5000 MWh, almost 1000 times that of ESS. NGK’s large installed capacity is reflective of the company’s long deployment history of sodium-sulfur (NAS) batteries which stretches back to 2001! Rongke Power comes second with 2000 MWh including a few recent multi-hundred MWh installations including the 175 MW / 700 MWh Xinhua Ushi ESS project in China.

The author notes that this article should be used for information purposes only. Comprehensive bankability reports can be obtained from renowned technical due diligence firms such as DNV. Feel free to reach out with any questions and feedback.