Company Website: https://www.hyliion.com/
AUSTIN, Texas -- (Business Wire)

Hyliion Holdings Corp. (NYSE American: HYLN), a developer of modular power plant technology, today announced the successful demonstration of an uninterrupted multi-fuel transition in its next-generation KARNO™ reactor design, capable of handling liquid and gaseous fuels seamlessly. Operating without any hardware changes, the system transitioned through natural gas, hydrogen, diesel, and back to natural gas in a continuous sequence.

The demonstration validates Hyliion’s integrated reactor architecture, in which gaseous and liquid fuel pathways are unified within one system rather than across specialized hardware configurations. Earlier KARNO milestones validated each fuel category on reactor designs optimized for that fuel type. This unified design, which adds to Hyliion’s extensive intellectual property portfolio, is the platform through which the Company is realizing its long-standing vision of true fuel-agnostic capability.

The demonstration, performed in Hyliion’s lab using an optical reactor configuration, enables direct visual observation of fuel behavior and provides engineering teams with real-time insight into reaction characteristics across fuel types. This capability supports continued refinement of the controls software that automatically detects fuel composition and adjusts operating parameters during transitions.

“True fuel agnostic capability is not a feature added to a Power Module. It has to be designed into the product architecture from the foundation,” said Thomas Healy, Founder and CEO of Hyliion. “When we acquired the KARNO technology, the long-term plan has always been to achieve a single architecture capable of operating across the full fuel spectrum. This demonstration confirms we are on the right path.”

The transition sequence executed during the demonstration covered fundamentally different oxidation regimes within a single reactor:

• Natural gas: the most widely available pipeline fuel and the baseline for distributed power applications
• Hydrogen: operated as a discrete fuel rather than as a blend
• Diesel: a liquid hydrocarbon, validating the integrated reactor’s ability to operate across phase boundaries
• Return to natural gas: confirming the architecture supports bidirectional transitions without recalibration

Stable operation during fuel transition across this sequence on the same hardware demonstrates that the controls system, internal architecture, and thermal management approach work consistently across fuel categories that conventional generators handle through separate product lines or hardware variants.

The implications across Hyliion’s priority markets are substantial. For data centers, a single KARNO Power Module can operate on pipeline natural gas under normal conditions and transition to alternative fuels during gas curtailments or supply disruptions, eliminating the need for separate backup generator systems.

In the case of defense applications, fuel flexibility translates directly to mission resilience. A fuel-agnostic generator reduces the need for fuel-specific variants in forward-deployed environments and can operate on whatever fuel the supply chain delivers.

“Unifying liquid and gaseous fuel pathways in a single reactor is an engineering problem we have been working on to truly unlock Stirling engine benefits,” said Josh Mook, Chief Technology Officer of Hyliion. “This demonstration confirms the architecture is sound, and that the KARNO technology can deliver flexible, on-site, on-demand power using various fuels the customer may choose.”

About Hyliion

Hyliion is committed to creating innovative solutions that enable clean, flexible and affordable electricity production. The Company’s primary focus is to provide modular power plant technology that can operate on various fuel sources to future-proof against an ever-changing energy economy. Headquartered in Austin, Texas, and with research and development in Cincinnati, Ohio, Hyliion is initially targeting the commercial and waste management industries with a locally deployable KARNO Power Module that can offer prime power as well as energy arbitrage opportunities. Beyond stationary power, Hyliion will address mobile applications such as vehicles and marine vessels. The Company aims to offer innovative, yet practical solutions that contribute positively to the environment in the energy economy. For further information, please visit www.hyliion.com.

Forward-Looking Statements

The information in this press release includes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements, other than statements of present or historical fact included in this press release, regarding Hyliion and its future financial and operational performance, as well as its strategy, future operations, estimated financial position, estimated revenues, and losses, projected costs, prospects, plans and objectives of management are forward looking statements. When used in this press release, including any oral statements made in connection therewith, the words “could,” “should,” “will,” “may,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “project,” the negative of such terms and other similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. These forward-looking statements are based on management’s current expectations and assumptions about future events and are based on currently available information as to the outcome and timing of future events.

Except as otherwise required by applicable law, Hyliion expressly disclaims any duty to update any forward-looking statements, all of which are expressly qualified by the statements herein, to reflect events or circumstances after the date of this press release. Hyliion cautions you that these forward-looking statements are subject to numerous risks and uncertainties, most of which are difficult to predict and many of which are beyond the control of Hyliion. These risks include, but are not limited to, our status as an early stage Company with a history of losses; our expectation of incurring significant expenses and continuing losses for the foreseeable future; our ability to develop key commercial relationships with suppliers and customers; our ability to retain the services of Thomas Healy, our Chief Executive Officer; the expected performance of the KARNO generator and system; the execution of the strategic shift from our powertrain business to our KARNO business, and the other risks and uncertainties described under the heading “Risk Factors” in our SEC filings including in our Annual Report (See item 1A. Risk Factors) on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on February 25, 2026 for the year ended December 31, 2025. Given these risks and uncertainties, readers are cautioned not to place undue reliance on such forward-looking statements. Should one or more of the risks or uncertainties described in this press release occur, or should underlying assumptions prove incorrect, actual results and plans could differ materially from those expressed in any forward-looking statements. Additional information concerning these and other factors that may impact Hyliion’s operations and projections can be found in its filings with the SEC. Hyliion’s SEC Filings are available publicly on the SEC’s website at www.sec.gov, and readers are urged to carefully review and consider the various disclosures made in such filings.

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Contacts:

Hyliion Holdings Corp.
press@hyliion.com
Investor Relations
ir@hyliion.com

Source: Hyliion Holdings Corp.