I just saw this in a "cool gadgets" segment on youtube. They said these are in 40,000 homes in Africa. They are going to be selling it here, in July, for "off the grid" living.
It is a biogas digester for food scraps. They say that an average family produces enough food scraps to produce 3 hours of cooking. It also produces liquid fertilizer.
They give you a little counter stove and a lamp that runs on biogas.
I live in a condo, so I can't have one, but I thought others might be interested.
https://homebiogas.com