(230f) Optimal Design and Integration of a Green Hydrogen Production, Compression and Storage System for Solar Photovoltaic Power Smoothing

With the increasing penetration of solar photovoltaic (PV) power into the electric grid, intermittent solar energy can lead to frequent and steep ramping operations of conventional fossil fuel power plants [1,2]. Green hydrogen production via water electrolysis using renewable solar power can serve as a controllable load and provide a short/long duration energy storage system for addressing load fluctuations (i.e., PV smoothing) and improve grid resiliency. The generated green hydrogen will be stored under high pressure (HD) for further use (e.g., hydrogen fuel cell electric vehicle refueling).

Polymer electrolyte membrane (PEM) electrolyzers with high efficiency and quick dynamic response can be used for hydrogen production [3,4]. The capacities of the solar field and PEM electrolyzer affect the maximum load of hydrogen production and the corresponding performance of PV smoothing on cloudy days. In addition, energy consumption for the high-pressure compression and storage of hydrogen should be considered in the integrated hydrogen system. Both size and operating pressure of compressor and HD storage vessels need to be optimized based on the tradeoff between capital expenditures and effectiveness of PV smoothing.

An integrated hydrogen-based energy storage system (renewable solar field coupled with green hydrogen production, compression and storage) was developed based on dynamic modeling. A high-fidelity dynamic model of a PEM electrolyzer cell/stack was established with consideration of the mass/heat transfer coupled with electrochemical kinetics. Multi-stage hydrogen compression with a cascaded vessel storage configuration was designed and modeled. Reduced order models (ROM) of hydrogen production, compression and storage were developed based on their nonlinear standalone models for optimal design and operation of electrolyzer/compressor/storage vessels under fluctuating solar power.

The integrated energy storage system must minimize PV fluctuations to the grid while maintaining electrolyzer durability. To evaluate the transient performance of the PEM electrolyzer stack and integrated energy system, real-time PV data from Orlando Utilities Commission (OUC) solar farm is smoothed using the optimal power signal control algorithm. The optimal PV smoothing algorithm has the predictive capability using the rolling-horizon approach and shows the effectiveness of hydrogen-based energy storage system in smoothing the PV signal to improve the grid stability and flexibility.

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[2] Wang, Y., Bhattacharyya, D., and Turton, R. (2019). Evaluation of Novel Configurations of Natural Gas Combined Cycle (NGCC) Power Plants for Load-Following Operation using Dynamic Modeling and Optimization. Energy and Fuels, 34(1), 1053-1070.

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[4] Götz, M., Lefebvre, J., Mörs, F., Koch, A.M., Graf, F., Bajohr, S., Reimert, R. and Kolb, T., 2016. Renewable Power-to-Gas: A technological and economic review. Renewable energy, 85, 1371-1390.