Lots of farms have biodigesters. But how do they work, and do they always cut emissions?

Cows release a super potent greenhouse gas when they burp and also when their poop breaks down. It’s called methane and a lot of farms in Vermont and around the country are trapping it to make electricity or natural gas.

Vermont Public partnered with NOVA to find out how it all works.

The James family has been milking cows — and bottling that milk — at their farm in Weybridge, Vermont since 1930. Today, they milk about 540 Holsteins, and the fourth generation is getting ready to take over the business.

On a chilly spring day, Bob James gave us a tour.

“It’s a free stall farm, so cows can get up, walk around, eat, drink, sleep whenever they want,” he said, as we walked through one of the barns.

Even though this is a small farm by national standards, all of those cows produce a lot of waste. But at Monument Farms, that waste has a second and even third life. They use it to make electricity and bedding for the herd.