ClearSign Technologies Successfully Completes Testing Of Its ClearSign Core Flexible Fuel, 100% Hydrogen Capable Process Burner Branded As ClearSign Core 2

Partnered with National Energy Technology Laboratory to Advance Flexible Fuel, Ultra-Low NOx Combustion for Industrial Operations

TULSA, OK / ACCESS Newswire / March 11, 2026 / ClearSign Technologies Corporation (NASDAQ:CLIR) ("ClearSign" or the "Company"), a leader in advanced combustion and sensing technologies that help industrial operators dramatically reduce emissions, increase efficiency and safety, and support the use of cleaner fuels including hydrogen, announces today that, in conjunction with the U.S. Department of Energy's ("DOE") National Energy Technology Laboratory ("NETL"), under its Small Business Innovation Research ("SBIR") program, it has successfully completed the testing of its ClearSign Core™ Flexible Fuel, 100% Hydrogen Capable process burner branded as ClearSign Core™ 2.