[cat_plus_plus]

Consider also having to rebuild things from scratch. Say a solar flare knocked out all your electronics or you are at war with your only supplier of rare earth metals. How quickly can you replace missing generators and appliances with devices that may be less efficient or clean and may only supply a small fraction of current power levels, but will at least let you turn lights and fridges back on? If mechanical turbines can generate A/C without advanced electronics and mechanical motors can run on that, it's not a bad precaution to keep these around.