Houston startup plans to store wind energy underground

The article, and the comments here, are missing an important fact that really helps clarify how these compressed-air energy storage systems work:<p>These systems use the compressed air as input into a natural gas turbine. You can think of the underground storage as a giant intercooler that stores the output of the first (compressor) half of a natural gas turbine, and then feeds that compressed air into the second (combustion) half.<p>See a good explanation here: <a href="http:&#x2F;&#x2F;energystorage.org&#x2F;compressed-air-energy-storage-caes" rel="nofollow">http:&#x2F;&#x2F;energystorage.org&#x2F;compressed-air-energy-storage-caes</a>

&quot;Apex will need a small amount of natural gas to heat the air it compresses to maximize turbine output.&quot;<p>As far as I understand they need to heat up the turbine as air (a gas) cools down upon (adiabatic) expansion.<p>And while accumulating &#x2F; compressing air in ground lacunae, pumping it into the storage, we are just heating up the ground.<p>Am I right in my understanding of the process thermodynamic ?

&gt; and the system can fill the cavern with air while generating electricity. You can&#x27;t charge and discharge a battery at the same time.<p>Umm, does this seem as pointless to everyone everyone else as me?

Glad to see something about houston on HN regardless of what the startup is doing! Woot woot