German utility RWE said supply of hard coal to its power plants at Bergkamen, Gersteinwerk and Westfalen were being affected by low water levels on the river Rhine.
"Continued low river levels are increasingly a challenge for transporting the coal [by river barge from the ARA region]," an RWE spokeswoman said Monday.
"As yet, this has not impacted power production at those plants. But, given the tense situation, we have decided to warn market participants on possible delays of coal deliveries," she said.
RWE issued a first short notice on Friday on its transparency website.
