You guys need to quit posting when you don't have a clue - your advice is absolutely wrong:
The Honda EU3000 only produces 3000 watts at peak,and 2800 watts continious load - not even half the power he would require to run his grow.
As I stated before he will need a minimun of 6500 watts peak, and 5500 watts continious load to run this grow.
If you were to buy the Honda EU6500 which is the minimum for this grow your fuel costs would be approx $32.40 per day to run just 12 hours per day flowering, and $48.6 per day vegging at 18 hours per day. This is based on fuel prices where I live, so your cost may be slightly higher or lower depending on local fuel prices.
So $1458 in fuel to veg. for 30 days, and $1814.4 to flower for 56 days (8 weeks) total electricity cost for one grow $3272.40, and this does not take into account the initial purchase price for the generator or any maintenance required to keep everything running.
That is an average of $272.70 per week just for fuel, and you will still have the power bill for the rest of your home on top of these costs.
The cost of buying the same amount of electricity thru my local electric Co. would be less than $500, or about $41 per week - again your local costs could differ slightly higher or lower.