Iran's electricity production right now presents a deficit of 10000 to 20000 MW, hence the current power cuts. Rohani's Minister of Energy was explicitly quoted as saying he will not bow to the "power plant construction mafia", meaning he does not want to accelerate the construction of power plants. And indeed, this government vastly fell behind schedule in terms of additional power generation as required by the Sixth Development Plan.
This is, in fact, the administration responsible for the smallest increase in electricity production ever since the early years of the Revolution! Whether Mousavi's, Hashemi's, Khatami's or Ahmadinejad's administrations, every single one of them increased power output by a (much) greater percentage.
Another reason for the power cuts is that elements linked to and acting on behalf of the liberal Rohani administration may be causing some of these cuts on purpose, as a way to anger the public, turn it against the entire system, and thereby compromise President-elect Ebrahim Raisi's popularity shortly before he takes office, or worse, trigger some form of domestic instability in guise of "revenge" for their defeat at the presidential election. Notice that in certain areas, power cuts are not even announced beforehand by the government!
Equally important to note is that cryptocurrency mining and the weather conditions, which have been named as reasons for the power cuts, are in fact nowhere to blame. The sum of legal and illegal cypto-mining activities in Iran is consuming a mere 660W of electricity. It is first and foremost the Rohani administration's failure to sufficiently invest in new power plants in order to satisfy the increase in national power consumption as accurately predicted by the Sixth Development Plan, which is at stake here.
