If they’re rolling blackouts on a predictable schedule, and if the plants are in veg, you may be able to get them on a candle lighting schedule. I have no experience with it personally, but I believe it was @monkman I saw running it most recently. It’s 3 sets of 6/2 instead of 18/6, and allows the plants do the same (if not more?), photosynthesis. Stay safe! 
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