Hydrogen Demonstration at Chevron’s Cymric 31X Cogeneration Site: Solar Centaur 40 SoLoNOx™ Gas Turbine

Abstract Chevron U.S.A. Inc. and Solar Turbines Incorporated (Solar) working in partnership with EPRI, demonstrated the long-term capability to operate a Solar Centaur 40 SoLoNOx industrial gas turbine on blends of natural gas and hydrogen up to 60% hydrogen by volume. Testing occurred at Chevron’s Cymric 31X cogeneration site near Bakersfield California as part of broader decarbonization efforts by both companies. The demonstration project involved developing and upgrading a 1980’s era facility and retrofitting the gas turbine package to test up to 60% hydrogen and operate over a twelvemonth period. A Centaur 40 SoLoNOx gas turbine engine with standard production hardware was used with package hardware and control logic upgrades to allow hydrogen operation. Chevron U.S.A. Inc. provided the hydrogen fuel supply, mixing skid and site upgrades for hydrogen operation. Facility work began in 2023 and engine testing started in early 2024. The demonstration was split up into two phases, with the first being a full characterization of the gas turbine operation, combustion system performance and emission levels with various hydrogen blends up to 60% hydrogen. This first phase also included load transients and engine starts. The second phase returned the gas turbine package to production operations and evaluated long term operation with hydrogen blends. The gas turbine demonstration has accumulated over 2,300 hours of operation on hydrogen blends with approximately 1,940 hours at or above 50% hydrogen and 485 hours at 60% hydrogen. Multiple inspections of the combustion hardware have shown no concerns. NOx levels were observed to increase with hydrogen addition utilizing the standard factory engine setup and control logic optimized for natural gas fuels. Data from testing has shown that natural gas fuel levels of NOx emission can be achieved for operation on hydrogen blended fuels by tuning of the engine combustion control software.