Hyliion's KARNO System Successfully Operates on Diesel Fuel, Expanding Fuel Flexibility

Hyliion Holdings Corp. (NYSE:HYLN), a developer of sustainable electricity-producing technology, today announced the successful operation of its full KARNO™ Core system on diesel fuel. This achievement marks a significant milestone towards the commercialization of the KARNO solution, confirming its operational effectiveness on liquid fuel in addition to its previously validated portfolio of gaseous fuels. During operation at the company's Cincinnati, Ohio facility, the KARNO system successfully exported power to the grid while meeting stringent Tier 4 Final (T4F) emission requirements without the need for after-treatment systems.

The successful diesel trial demonstrates the KARNO's unique fuel flexibility which positions it as a competitive power generating solution across a wide range of applications and industries. The KARNO Power module is designed to operate on over 20 fuels, enabling customers to deploy systems using conventional fuels today and seamlessly transition to low-carbon and renewable options as they become more widely available. This versatility reduces customer risk and preserves long-term assets.

Traditional T4F diesel generators rely on complex exhaust after-treatment systems such as SCR, DPF, and ongoing DEF consumption. By contrast, the KARNO Power Module is designed to meet T4F requirements without emissions after-treatment hardware, reducing system complexity and operating costs while improving reliability.

"Operating on liquid fuels meaningfully expands our addressable market and strengthens energy resiliency for customers, including supporting our upcoming deployments in defense applications where diesel is the preferred fuel," said Thomas Healy, Founder and CEO of Hyliion. "In other mission-critical environments like data centers, the KARNO Power Module will be able to seamlessly switch to onsite diesel if primary fuel sources like pipeline gas are disrupted or unavailable."

The KARNO Power Module leverages advanced thermodynamics and 3D metal additive manufacturing to generate electricity from heat, rather than traditional combustion. Its fuel-agnostic design enables the system to operate seamlessly on a range of liquid and gaseous fuels including natural gas, hydrogen, ammonia, propane, and diesel, supporting Hyliion's mission to enable clean, flexible and scalable electricity generation across a wide range of applications and industries.

Hyliion plans to incorporate diesel fuel capability into customer-deployed KARNO Cores beginning in 2026, further expanding the platform's fuel flexibility and enhancing resiliency for mission-critical applications.