My 400 watt hps grow, a few 4 inch fans, and a 150 watt t5 for veg and moms increased my bill about 50-60$ a month. That one is in Northern California. Another grow in So Cal we use a 600 hps and a 250 t5 for vegging and some 6 inch fans and for some reason that grow increased the bill by 250$ a month. I did not get it. I think so cal is more expensive than where I am here. That bill kind of freaked me out, until harvest time. Then it was all worth it. So you might freak out. I would keep the hps.
Your grow is set up really nice.