ESS Tech : Conference Call to Discuss Honeywell Investment Presentation

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Catalyzing

a Clean Future.

Every Day.

Honeywell Strategic Relationship

September 25, 2023

Disclaimers

This presentation includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act"), and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). These forward-looking statements can be identified by the use of forward-looking terminology, including the words "believes," "estimates," "anticipates," "expects," "intends," "plans," "possible," "may," "might," "will," "potential," "projects," "predicts," "continue," "could," "would" or "should," or, in each case, their negative or other variations or comparable terminology. These words and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements, which are subject to risks, uncertainties and assumptions about us, may include statements regarding the collaboration between ESS and Honeywell and Honeywell purchasing products from ESS. These statements are based on management's current expectations, but actual results may differ materially due to various factors, risks, and uncertainties, including, but not limited to: our financial and business performance, including disruptions, or quality control problems in the Company's manufacturing operations; challenges related to the collaboration between ESS and Honeywell, financial projections and business metrics; changes in our strategy, future operations, financial position, estimated revenues and losses, projected costs, prospects and plans; the implementation, market acceptance and success of our technology implementation and business model; our ability to scale in a cost- effective manner; developments and projections relating to our competitors and industry; our expectations regarding our ability to obtain and maintain intellectual property protection and not infringe on the rights of others; our future capital requirements and sources and uses of cash; our ability to obtain funding for our operations; our business, expansion plans and opportunities; our relationships with third-parties, including our suppliers, customers, and partners; issues related to the shipment and installation of our products; issues related to customer acceptance of our products; the outcome of any known and unknown litigation and regulatory proceedings; and other risks and uncertainties discussed elsewhere in our public filings. The forward-looking statements contained in this report are based on our current expectations and beliefs concerning future developments and their potential effects on us. There can be no assurance that future developments affecting us will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) and other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws. These risks may not be exhaustive. By their nature, forward-looking statements involve risks and uncertainties because they relate to events and depend on circumstances that may or may not occur in the future. We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and developments in the industry in which we operate may differ materially from those made in or suggested by the forward-looking statements contained in this report. In addition, even if our results or operations, financial condition and liquidity, and developments in the industry in which we operate are consistent with the forward-looking statements contained in this report, those results or developments may not be indicative of results or developments in subsequent periods.

All rights to the trademarks, copyrights, logos and other intellectual property listed herein belong to their respective owners and ESS's use thereof does not imply an affiliation with, or endorsement by the owners of such trademarks, copyrights, logos and other intellectual property. Solely for convenience, trademarks and trade names referred to in this Presentation may appear with the ® or ™ symbols, but such references are not intended to indicate, in any way, that such names and logos are trademarks or registered trademarks of ESS.

Any financial and operating forecasts and projections contained herein represent certain estimates of ESS as of the date thereof. ESS's independent public accountants have not examined, reviewed or compiled the forecasts or projections and, accordingly, neither expresses an opinion or other form of assurance with respect thereto. ESS and its management team cannot give any assurance that the forecasts or projections contained herein accurately represent ESS's future operations or financial conditions. Such information is subject to a wide variety of significant business, economic and competitive risks and uncertainties, including but not limited to those set forth above that could cause actual results to differ materially from those contained in the prospective financial information. Accordingly, there can be no assurance that the prospective results are indicative of the future performance of ESS or that actual results will not differ materially from those presented in the prospective financial information. Some of the assumptions upon which the projections are based inevitably will not materialize and unanticipated events may occur that could affect results. Therefore, actual results achieved during the periods covered by the projections may vary and may vary materially from the projected results. Inclusion of the prospective financial information in this presentation should not be regarded as a representation by any person that the results contained in the prospective financial information are indicative of future results or will be achieved.

This Presentation contains statistical data, estimates and forecasts that are based on independent industry publications or other publicly available information. This information involves many assumptions and limitations and you are cautioned not to give undue weight to these estimates. We have not independently verified the accuracy or completeness of the data that has been contained in these industry publications and other publicly available information. Accordingly, neither ESS nor its respective affiliates and advisors makes any representations as to the accuracy or completeness of these data. This Presentation contains references to ESS's achievements compared to other companies. All of such references are based on the belief of ESS's management based on publicly available information known to ESS's management.

The financial information and data contained in this Presentation is unaudited and does not conform to Regulation S-X promulgated under the Securities Act of 1933, as amended.

Catalyzing a Clean Future. Every Day.

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ESS &

Broad ranging strategic relationship to redefine the Long-Duration Energy Storage (LDES) category

: A Category-Defining Relationship

Accelerates		Validates ESS's
technology
	proprietary iron
innovation and
	flow technology as
value creation
	market-leading
through the energy
	LDES technology
transition

Catalyzing a Clean Future. Every Day.

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LDES is Key to Energy Transition

COP 26: Major global report by McKinsey & Co. found that LDES is key to energy transition

• LDES sits between
  lithium batteries and hydrogen
• LDES defined as two categories: 8-24h and >24h storage
• Lithium will continue to play a role for <6h but not appropriate for longer durations

Catalyzing a Clean Future. Every Day.

More information: www.ldescouncil.com

LDES Expected to Receive up to $3T in Cumulative Investment by 2040

~$50B

~$200-500B

~$1100-1800B

~$1500-3000B

~85-140 TWh

140

120

100			~35-70 TWh
80
60
40	~1 TWh	~5-10 TWh
20
0
	2025	2030	2035	2040

TWh Cumulative installed energy capacity

1 TWh = 1 million MWhs

Catalyzing a Clean Future. Every Day.

More information: www.ldescouncil.com

USD bn est. cumulative capex investment

$3 Trillion investment in energy storage required by 2040

With LDES, total energy system costs can go down

Renewable power with

LDES can be cost effective

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