Just to make sure you're not talking passed each other, I think @miimura is talking about the concern we often here about distributed resources straining system operations; but if they aren't measured, how do they know? @Ampster, I think you're going to the point about utilities disliking distributed resources because they can't earn a return on them, while they do on utility-owned generation and the associated transmission assets. Both are fair, but separate, points.
Re @Ampster's "fairly state their costs," this is a really complicated issue. Utilities already have an army of internal, external, and state auditors looking at their books, so I think it's safe to say that the numbers used in rate case are "hard". What's squishy is the allocation among rate classes and line items with in a rate. E.g., should all transmission costs be treated as fixed, because in the short run nothing changes by using them more, or variable, because heavily used lines will eventually be upgraded to handle the extra flow? Even if the costs are considered fix, what specific metric should be used to allocate to residential, commercial, industrial, and municipal customers? There are a lot of precedents for answering these questions, but nothing that is obviously "right".
