(692c) Technoeconomic Analysis and Optimization of Low Carbon, Reforming-Based Integrated Energy Systems for the Co-Production of Hydrogen and Power

Hydrogen has a strategic importance in the pursuit of a decarbonized, more sustainable energy sector. Integrated Energy Systems (IES) based around hydrogen production and use have the potential to synergistically provide multiple services such as electricity, high value heat, and chemicals as part of dynamic, tightly coupled hybrid systems. This work explores combining a natural gas turbine (GT), a steam methane reforming (SMR) process, and carbon capture to create an IES capable of generating nearly carbon-free hydrogen and power. The GT provides electricity for on-site use, thereby eliminating the need for a stable external power source, and for sale as a co-product when electricity prices are high. In comparison to standalone systems for power and hydrogen generation, the IES concept enables significant savings in capital and maintenance costs due to the sharing of much of the same equipment, such as the carbon capture and compression system, as well as lower variable costs through process and heat integration.

Two IES process configurations – an SMR with a natural gas simple cycle (NGSC) and an SMR with a natural gas combined cycle (NGCC) – are optimized and analyzed using the open-source Institute for the Design of Advanced Energy Systems (IDAES) Integrated Platform [1-3]. In both cases, oxygen-rich flue gas exhaust from the GT is fed to the burners of the SMR furnace in place of air. In the SMR + NGSC design, the flue gas leaving the furnace enters a heat recovery system that preheats the natural gas to be reformed and generates steam for process use. In the SMR + NGCC configuration, the flue gas also passes through a heat recovery steam generator and steam turbine to generate additional power. Flue gas from each system then enters a solvent-based post-combustion carbon capture system as well as a compression and purification unit before being transported through a pipeline for long term geologic storage.

In comparison to standalone systems for power and hydrogen, the IES designs achieve higher thermal efficiencies by recovering the sensible heat contained in the gas turbine exhaust. Additionally, the total amount of flue gas for the IES designs is over 40% lower than standalone systems resulting in smaller carbon capture equipment. Such advantages result in significantly lower levelized cost of hydrogen (LCOH) ($/kg) compared to a standalone SMR with carbon capture [4] after considering a credit for electricity sales. The impact of several economic parameters such as natural gas price, electricity price, carbon price, and capacity factor are analyzed to more fully understand the value proposition of the IES designs. Deployment opportunities are analyzed in the context of a future regional electricity market by coupling the process with locational marginal price signals using a price taker assumption. As expected, the benefit of the IES becomes more pronounced at higher electricity prices, thereby insulating the system from potential future scenarios where the price of electricity is high.

Disclaimer

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

References

[1] D. C. Miller, J. D. Siirola, D. Agarwal, A. P. Burgard, A. Lee, J. C. Eslick, B. Nicholson, C. Laird, L. T. Biegler, D. Bhattacharya, N. V. Sahinidis, I. E. Grossmann, C. E. Gounaris and D. Gunter, "Next Generation Multi-Scale Process Systems Engineering Framework," Computer Aided Chemical Engineering, vol. 44, pp. 2209-2214, 2018.

[2] A. Lee, J. H. Ghouse, J. C. Eslick, C. D. Laird, J. D. Siirola, M. A. Zamarripa, D. Gunter, J. H. Shinn, A. Dowling, D. Bhattacharyya, L. T. Biegler, A. P. Burgard and D. C. Miller, "The IDAES process modeling framewrok and modeling library - Flexibility for process simulation, optimization and control," Journal of Advanced Manufacturing and Processing, vol. e10095, no. https://doi.org/10.1002/amp2.10095, 2021.

[3] https://idaes-pse.readthedocs.io/en/stable/.

[4] E. Lewis, S. McNaul, M. Jamieson, M.S. Henriksen, H.S. Matthews, L. Walsh, J. Grove, T. Schultz, T.J. Skone, and R. Stevens, “Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies,” DOE/NETL-2022/3241.