They use a significantly more electricity than the average residential home. However it’s tiny amount compared to the average business/factory usage. It will hardly cause a blip on the network.
Say they use 20 watts of LED lights per sq ft per hour. With 2000sq ft of grow space over a 12 hour photoperiod that’s 480KWh per day.
The average home uses around 30kwh with 50% of that for climate control. So an additional 15KWh per day for climate control.
Dedicated grow houses are looking at using around 500KWh per day. It will definitely stand out on the billing. They are using 16-17 times more energy than other homes.