[r9etb]

In a sense, this is managing to capture some solar energy that otherwise would not have been conserved...

Agreed. However, I believe the energy balance is negative: it takes more energy to raise a turkey (or whatever) than you can recover from its crap and offal, which is why I'm calling it "energy recovery."

[null and void]

The alternative is to throw away the stored energy. Worse, the alternative is to PAY to throw away the stored energy...