Underground storage of hydrogen with natural gas (UHNG) is a novel compound technology which has been proposed to provide utility-scale energy storage capacity. This technology revolves around the use of electrolyzers to convert electrical energy to chemical energy in the form of hydrogen, then, hydrogen is injected underground, along with natural gas, into existing natural gas storage facilities. Finally, depending on the particular application, the energy stored as hydrogen can be recovered in different forms: as hydrogen for industrial and transportation applications, as electricity to serve power demand, or as hydrogen-enriched natural gas to serve gas demand. It is found that, if operated as the decision points have specified, at the end of three years, the concentration of hydrogen in the reservoir is expected to increase to 2%. Also, it is found that it is not profitable to sell the hydrogen-enriched natural gas at the same price as regular natural gas.