It's badly worded, but most people should get the meaning in context of talking about capacity factor. "Every minute of every day" is just a common English exp

It's badly worded, but most people should get the meaning in context of talking about capacity factor. "Every minute of every day" is just a common English expression to mean "all the time." The word "minute" in there isn't significant and doesn't factor in the calculation, it's just for emphasis. So really all the author means is "producing 30MW consistently for the whole time it's been in operation." Or if they did use minutes as a time slice in the capacity calculation, it would have to be "averaging 30MW during every minute of every day".