Megacalories to terawatt hours converter on this page calculates how many terawatt hours are in 'X' megacalories (where 'X' is the number of megacalories to convert to terawatt hours). In order to convert a value from megacalories to terawatt hours (from Mcal to TWh) simply type the number of Mcal to be converted to TWh and then click on the 'convert' button.