The problem is that generating ATP requires sun or sugar in plants (depending on the specific metabolic process involved), and that the total amount of sugar produced during the day as part of photosynthesis is tiny relative to the amount of ATP necessary to fuel the light at night.

Consider that humans burn 100-150 kilos of ATP daily (according to Wikipedia). This is only possible because we are recycling ATP continuously, fueling the recycling process with sugar and oxygen that we consume at rates several orders of magnitude higher than what a 20 year old tree could produce in the same period.

I can't find numbers for peak sugar production in plants, but considering how many maple trees it takes to make a single small container of maple syrup, I think this is a reasonable statement to make for now. I will stand corrected if someone has good numbers. :)