Decarbonizing the Power Sector: A Viable Pathway for NGCC Plants

Strategic Insights -

Research on decarbonizing the power sector has shed light on a promising solution for utilizing existing fossil fuel-based power plants while achieving net-zero emissions targets. According to a new study published in the Journal of Cleaner Production, a 50:50 mixture of hydrogen (H2) and ammonia (NH3) offers a viable alternative to natural gas (NG) in power generation. This approach not only provides a comparable flame speed to NG but also addresses key limitations of conventional H2 and NH3 production pathways.

The study, conducted by researchers at the University of Tokyo, investigated the integration of biomass-based chemical looping hydrogen generation (CLHG), NH3 synthesis, and an existing 500 MW NGCC power plant through process simulation and off-design analysis. The results showed that the CLHG system achieved an H2 production efficiency of 75%, while the NH3 synthesis process exhibited an efficiency of 63%. When NG was replaced by the H2-NH3 mixture, the overall efficiency of the system decreased from 56.19% to 47.1%, primarily due to fuel production processes.

Key Takeaways:

  • A 50:50 mixture of H2 and NH3 offers a viable solution for decarbonizing the power sector, providing a comparable flame speed to NG while addressing limitations of conventional H2 and NH3 production pathways.
  • The integration of biomass-based CLHG, NH3 synthesis, and an existing 500 MW NGCC power plant through process simulation and off-design analysis showed a promising pathway for decarbonizing NGCC plants.
  • The CLHG system achieved an H2 production efficiency of 75%, while the NH3 synthesis process exhibited an efficiency of 63%.
  • The overall efficiency of the system decreased from 56.19% to 47.1% when NG was replaced by the H2-NH3 mixture primarily due to fuel production processes.
  • The calculated levelized cost of electricity for the integrated system was 0.1075 USD/kWh, lower than that of imported fuels.
  • The levelized costs of H2 and NH3 were 1.439 USD/kg-H2 and 0.365 USD/kg-NH3, respectively.
  • The study suggests that leveraging a steady-state CLHG-NH3 system with flexible NGCC operation presents a viable pathway for decarbonizing NGCC plants while ensuring cost competitiveness in a transitioning energy market.

Statistics:

  • 75%: H2 production efficiency of the CLHG system
  • 63%: Efficiency of the NH3 synthesis process
  • 56.19%: Overall efficiency of the system with NG
  • 47.1%: Overall efficiency of the system with H2-NH3 mixture
  • 0.1075 USD/kWh: Calculated levelized cost of electricity for the integrated system
  • 1.439 USD/kg-H2: Levelized cost of H2
  • 0.365 USD/kg-NH3: Levelized cost of NH3

Sources:

  • Retrofitting the Natural Gas Combined Cycle Through Integration With Chemical Looping Hydrogen Generation and Ammonia Synthesis Toward a Carbon-neutral Trigeneration System. Journal of Cleaner Production, 2025;513.
  • Elsevier Sci Ltd, 125 London Wall, London, England. (Elsevier - www.elsevier.com; Journal of Cleaner Production - www.journals.elsevier.com/journal-of-cleaner-production/)
  • Muhammad Aziz, University of Tokyo, Dept. of Mechanical Engineering, 7-3-1 Hongo, Bunkyo Ku, Tokyo 1138656, Japan.