The power company can tell exactly how much load goes into each grid section. If the load doesn't match the money, they investigate. I don't trust anything that claims to cut my power bill like that. Probably will just cause problems.
Most people that get busted do it by stealing electricity. You really have to be doing a lot for them to investigate you for power consumption. If you want to grow do it, just be sure you know who is allowed in your home and don't tell any one other than the millions of strangers online that you grow and you can do it safely so long as you PAY YOUR BILL!!