I’m copying below a comment at the linked site refuting the silliness of this article:
“ I am an engineer, and at one point worked in the nat gas industry. There are three principal means of gas storage. The dominant one in terms of capacity is underground storage. Gas is pumped into underground cavities—these are not huge caverns, as some imagine them, but typically volumes of porous rock left over after petroleum or saline extraction—under high pressure, often 200 bar (1 bar is atmospheric pressure). When gas is re-extracted from them, all but 1 bar of pressure can be recovered, leaving only 0.5% of gas, under atmospheric pressure, in the ground. The idea of “flushing” these cavities with new gas is stark nonsense; the net result would be that you would be replacing that remaining atmospheric pressure gas with other gas, for no net gain. 99% of the gas in these cavities can be recovered, 0.5% (or more, depending on local geology) is lost to leakage within ground, and 0.5% remains at atmospheric pressure. Then if gas is available, the storage can be refilled.
The other, much smaller volume of storage is in aboveground tanks, at atmospheric pressure. These tanks have mobile roofs with liquid edge seals—lids in effect—that seal the top of the gas storage, and move down as gas is depleted. Their weight supplies some of the pressure to get the gas out, but mostly it is just pumped out with compressors (which can act as vacuum pumps quite well) and the roof follows it down. No “flushing with other gas” is done, either. These tanks have the convenience of being able to be erected anywhere regardless of local geology, and mostly serve as on-site storage for gas powerplants or gas-processing petrochemical facilities.
The third type, recently increasing, is LNG storage. These tanks are the smallest, because they must be slightly pressurized, and so their structure must be much more robust. Often, they are buried underground, but this is for better thermal insulation rather than for pressure support. The LNG tanks hold the gas in liquid form, much more condensed than even the underground 200bar facilities, but the downside is that the gas must be refrigerated to very low temperatures to remain liquid at near-atmospheric pressures. This is not like the bottled *propane* gas that can be stored liquid at room temperatures. And guess what, there is no “flushing out” with other gas going on here as well.
In conclusion, the concept of getting gas out of storage by forcing it out with the same amount of “fresh” natural gas is utter nonsense, as even a moment of considered reflection will make obvious. You could, I suppose, try to flush it out with a neutral gas like nitrogen, but what you would get out of it is a dilute mixture of methane and nitrogen, and it would make no sense economically, as nitrogen is expensive to obtain, in terms of energy—you obtain it in industrial quantities by refrigerating air until it liquefies, then distilling oxygen and nitrogen apart. You cannot flush the gas out with air, because at some point an explosive mix would be reached.”
Yes, I've seen these.