This is a cute idea for a movie and all but it’s incredibly impractical/unsustainable. If a system required that it’s energy storage be self-replicating (for whatever reason) then you would design and fabricate that energy storage solution for that system. Not be reliant on a calorically inefficiently produced sub-system (i.e. humans).

You literally need to grow an entire human just to store energy in it. Realistically, you’re looking at overfeeding a population with as much calorically dense, yet minimally energy intensive foodstuffs just to store energy in a material that’s less performant than paraffin wax (body fat has an energy density of about 39 MJ/kg versus paraffin wax at about 42 MJ/kg). That’s not to speak of the inefficiencies of the mixture of the storage medium (human muscle is about 5 times less energy dense than fat).