welp - thats 136W x 18 hours = 2.448 KWh/day

2.5 KWh x 4.6c/kwh = about .10 cents a day to run the lights... Nice! Even 1000 watts would be under $1.00 a day...

So your lights are ~ 3.00 a month to run, + whatever the base service fee is.. not too shabby

Where I used to live in cali it peaked at about .37 a KWH.. ridiculous

My current rate is .04816, so just under 5c a KWH, about the same as yours