Enabling utility-scale electrical energy storage by a power-to-gas energy hub and underground storage of hydrogen and natural gas

Abstract

With the increased use of renewable energy, energy storage technologies are becoming increasingly important. One such technology is Power-to-Gas, which can provide seasonal energy storage by utilizing both the electrical and natural gas infrastructures through injecting hydrogen into existing gas infrastructure to create Underground Storage of Hydrogen and Natural Gas (UHNG). The hydrogen is recovered from the mixture as needed for industry or transportation applications, converted to electricity to meet power demand, or kept as a mixture of hydrogen-enriched natural gas to serve gas demand. Large scale energy storage is desirable to energy generation operators for its ability to manage excess base load energy, integrate renewable energy into the grid and provide long term energy storage. The authors investigate the financial and environmental performance of specific scenarios of UHNG produced by Power-to-Gas through scenario-based simulations in a MATLAB/Simulink for comparative purposes. The simulated scenarios include the injection of hydrogen for long term storage, load shifting, renewable energy integration and supplying a large hydrogen demand. All of these scenarios are compared to a base case which simulates the operations of a conventional underground gas storage facility. The analysis illustrates that existing natural gas storage practices are driven by variations in the demand for natural gas. The most desirable pathway for energy recovery and revenue in this analysis occurs when hydrogen is injected into the reservoir along with natural gas and is distributed to off-site users.