Im sure it depends on the plant, as im basing this on weed growing info, but with the top economical growing LEDs take 35-50 watts per square foot. With vegetative growth possible down to 11 W/sqft but at a much slower rate.

At a cost of atleast $2 a per watt for lights (possibly up to $4 a square foot for industrial/commercial electrical rating) and assuming 35 watts per square foot, a 2000 square foot grow space, you are looking at $140,000 in LEDs alone. plus 70KW for 16 hours a day(+10% more for supply inefficiencies), that's about 1200 kilowatt hours of power needed to supply daily. Not sure how many panels that is but it has to be a lot.