You don't build a pretreatment plant if you're only using a fraction of its capacity. You'd instead just ship in pre-treated methane by pipeline or by truck.
But that's not what SpaceX is asking for. SpaceX is asking for their own, private, pretreatment plant. For... some reason. (The underlying theory is: SpaceX seems to be trying to mine their own natural gas)
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EDIT: And if the power plant was expected to be operating at only a minor fraction of the year, you'd expect something in the PEA to note that fact.
Do you see any reason to disagree with this 45.8 number?
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If you do have beef with other blogposts / other things (It seems like you want to talk about the power plant), you're welcome to do so. But my earlier points in this thread are rather specific to this #16 blogpost.