They are exaggerating the hell out of influence of miners on the electricity consumption increase and their role in power outages.
There has always been an increase in annual power consumption in Iran while the increase in power production hasn't been able to meet that increasing demand. If you check the statistics for every year for example 1399, 1398 and 1397 you can see the increase in consumption and not enough increase in production.
There are a couple of factors affecting it such as the population growth, decreased rain leading to decreased power production, old power plants that don't have the spare parts to upgrade or fix their plant due to sanctions, lack of fuel to use in plants,...
For example 1398 (2 years ago) electricity produced from water in dams was reduced by 7% and in 1399 (last year) it was reduced by 15.2%.
Part of it is mitigated by the nuclear power plants but if you check the dates the power outages started becoming worse ever since a month ago after the terrorist attack on the Iranian power plants that despite what they admit ceased its electricity production.