Newport has no costs on UK PowerGrid map - A misprint?
Yes, it's a misprint. From the game publisher:


  Oh, that is a misprint. As far as I can check this, all three numbers
  are missing in Newport. Of course this city should have the same
  numbers as all normal cities (10/15/20).
  
  Sorry!
  
  Henning (2F-Spiele)