I was part of the discussion on Steam mentioned above. The confusion came about because the Wiki says the power plants consume "unprocessed" oil and ore, which most people have apparently assumed meant pure, extraction level "oil" and "coal".
After several of us did numerous tests, it appeared that the only commodity delivered to power plants (per the trucks doing the delivering) was "oil products" or "ore products" from imports, recycling plants, or Zoned (Specialized) Oil / Ore District processors.
Trucks from DLC Industries Oil / Ore Areas, carrying "oil" and "coal" from extraction points NEVER delivered to Power Plants. They would, however, deliver to a Zoned Oil / Ore District which in turn, would send "oil / ore products" to the Power Plants.
Additionally, DLC Warehouses, holding "Zoned Industry Oil / Ore Products" WOULD deliver the "products" to the Power Plants, but Industries DLC storage facilities, such as the Crude Oil Tank Farm, which hold primary level extraction resources (i.e. "unprocessed oil and coal"), would NOT deliver to the Power Plants.
This is sort of consistent with the Wiki saying "Further supplies of oil and coal [for the power plants] can be produced by the appropriate regions of specialized industry" Again, though, not clear because the trucks from the Zoned Specialized Industry Areas say they're carrying "oil / ore products", not the oil or coal that the power plants supposedly consume.
Thus the confusion when the Wiki says the power plants "consume" unprocessed oil or coal -- no truck actually says it is delivering that commodity.
The "oil / coal" vs." oil / ore products" discussion may just be a question of semantics. But our testing indicated that from the Industries DLC Oil / Ore Areas, no trucks delivered to power plants from either extraction level facilities or from storage facilities.
Happy to be proven incorrect or to have this clarified further by someone more knowledgable.