A baby cow was born a day before my visit to Li Youqing's home in Nandeng village. The cow was still too weak to stand, curling up in a corner of the house, completely unaware of the elation and promise his birth brought to the family.

Nandeng village is home to some 200 Bai families. Along with five other villages, it is quietly seated in the middle of a lake, which is the major origin of Dali's mother lake, Erhai. Here, dairy cattle are perhaps the most important thing in people's lives – not only in Nandeng, but in all of Eryuan county. With the local milk, people founded their own brand, Diequan Dairy, in 1959, which sells well all across Yunnan province and has even made its way to countries in Southeast Asia.

But milk is not the only byproduct of the Nandeng cow population. Each of them also produces 100 kilograms of manure every day! In Nandeng village, there are around 350 cows, so together they make 35,000 kilograms of poop each day.

You may picture the village filled with piles of disgusting, smelly poops, but the manure is not totally useless. It is the ideal raw material to make methane. After fermentation at the village’s methane station, it is carried through pipelines to homes as fuel for daily use.

Thanks to the recycling system, about one-third of the families in Nandeng village are now using methane as their main source of fuel. It is much cleaner and more efficient than coal or firewood. Villagers can buy methane at 0.4 yuan (about $.06) per cubic meter. Or they can trade cow manure; one ton of poop is worth 50 yuan or 125 cubic meters of methane.

Also see:

Slideshow

Villages in Dali: Deep in the mountains

Villages in Dali: Home of silversmiths

Video: Christie Lee

Producer: Flora Yue