Flexible dispatch strategy for electric grid integrating PEM electrolyzer for hydrogen generation

Abstract

Proton exchange membrane (PEM) electrolyzer (EL) is regarded as a promising technology for hydrogen generation, offering load flexibility for electric grids (EGs), especially those with a high penetration of renewable energy (RE) sources. This paper proposes a PEM-focused economic dispatch strategy for EG integrated with wind-electrolysis systems. Existing strategies commonly assume a constant efficiency coefficient to model the EL, while the proposed strategy incorporates a bottom-up PEM EL model characterized by a part-load efficiency curve, which accurately represents the nonlinear hydrogen production performance, capturing efficiency variations at different loads. To model this, it first establishes a 0D electrochemical model to derive the polarization curve. Next, it accounts for the hydrogen and oxygen crossover phenomena, represented by the Faraday efficiency, to correct the stack efficiency curve. Finally, it includes the power consumption of ancillary equipment to obtain the nonlinear part-load system efficiency. This strategy is validated using the PJM-5 bus test system with coal-fired generators (CFGs) and is compared with a simple EL model using constant efficiency under three scenarios. The results show that the EL modeling method significantly influences both the dispatch outcome and the economic performance. Sensitivity analyses on coal and hydrogen prices indicate that, for this case study, the proposed strategy is economically advantageous when the coal price is below 121.6 $/tonne. Additionally, the difference in total annual operating cost between using the efficiency curve anda constant efficiency to model becomes apparent when the hydrogen price ranges from 2.9 to 5.4 $/kg.

Graphical abstract

Keywords

proton exchange membrane electrolyzer (PEM EL) / nonlinear part-load efficiency / optimal dispatch strategy / hydrogen / wind energy

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Acknowledgements

This work was supported by National Key R&D Program of China (Grant No. 2021YFE0191200), which has received funding from Ministry of Science and Technology of the People’s Republic of China.

Competing Interests

The authors declare that they have no competing interests.

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11708-025-0976-6 and is accessible for authorized users.

Notations

Abbreviations
AC	Alternating current
ASR	Area specific resistance, Ω·cm2
CFG	Coal-fired generator
DC	Direct current
EG	Electric grid
EL	Electrolyzer
FC	Fuel cost, $
LHV	Lower heating value, kJ/mol
PEM	Proton exchange membrane
PSU	Power supply unit
RU/RD	Ramp-up and -down rate, %
TC	Total operating cost, $
WPP	Wind power plant
WP	Water pump
Symbols
ṁt	Produced hydrogen at hour t, kg
m,n	Characteristic parameters of wind turbine
P_{i,t}^{\mathrm{e}}	Power load of the EL which is connected to bus i at hour t, MW
Pe,nom	Nominal power of the EL, MW
Pg,t	Power output of gth coal-fired generator at hour t, MW
P_g^{min}/P_g^{max}	Minimum/maximum operating limit of gth CFG, MW
Pij,t	Active power flow of branch connecting bus i to j at hour t, MW
Li,t	Electric power demand in bus i at hour t, MW
P_{i,t}^{\mathrm{w}}	Integrated wind power from the WPP which is connected to bus i at hour t, MW
P_{i,t}^{\mathrm{w}\mathrm{a}}	Available wind power from the WPP which is connected to bus i at hour t, MW
P_{i,t}^{\mathrm{w}\mathrm{c}}	Wind curtailment from the WPP which is connected to bus i at hour t, MW
Pw,nom	Nominal power of the WPP, MW
r_t^{\mathrm{e}}	Partial load factor of the EL at hour tv Wind velocity, m/s
xij	Reactance of branch connecting bus i to j, pu
Greek
δi	Voltage angle in bus i, rad
{\eta }_t^{\mathrm{e}}	EL efficiency at hour t
λ	Marginal cost of hydrogen, $/kg
Subscripts/Superscripts
act	Activation
an	Anode
cat	Cathode
elec	Electrically conductive components
mem	Membrane
ohm	Ohmic
ref	Reference
rev	Reversible
tn	Thermoneutral
Indices and sets
g	Index of CFGs
i, j	Index of electric buses
t	Index of hours
{\mathrm{\Omega }}_{\mathrm{G}}^i	Set of all CFGs connected to bus i
{\mathrm{\Omega }}_l^i	Set of all branches connected to bus i

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