Running 4KW of lights, and fans etc, you can look to double your power bill. This will definately be an attention getter. If you want to reduce your power consumption, and not raise any red flags, start by replacing your heating and cooling system with a new super energy efficient model... that will reduce your current power bills 30 - 50%, then start up the lights in conjunction with having the new system installed. This will keep you from raising red flags with the power company. No its not gonna be free.

OTOH, 4KW of lights and a sea of green sounds like a commercial grow. Maybe you should clarify here. This site is for medical marijuana and personal use. There are other sites if your growing quantities for sale. Just sayin.