Dairy Technology in Ellington Converts Manure to Natural Gas

Seth Bahler, CEO of Oakridge Dairy Farm in Ellington, talks about the farm's methane digester that converts 70,000 gallons of manure per day to natural gas. (CT Examiner)


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ELLINGTON — A fifth-generation dairy farm is the first in the state to invest in a methane digester that converts cow manure into natural gas. 

“We’re just trying to make a difference in the ag world and trying to take the farm to the future – that’s really our goal,” said Seth Bahler, CEO of Oakridge Dairy Farm. 

The dairy’s 3,000 Holstein cows produce about 25,000 gallons of milk per day, or about 18 percent of the state’s milk production, said Bahler.

“A cow eats about 100 pounds of food a day, drinks about 30 to 50 gallons of water. About 75 percent of that food that she consumes is used to keep her happy, healthy and producing milk,” he said. “So 25 percent of the energy that she’s consumed passes through and it’s out in the manure.”

That adds up to about 70,000 gallons of cow manure per day that is piped underground into the new $15 million anaerobic digester, which was built to replicate a cow’s stomach, but with a 2 million gallon capacity. 

“We’re heating up [the manure] to 101 degrees, it’s in there for about 21 days and that’s capturing all the energy that’s left in the manure,” he said. 

Next, the natural gas is piped through a refining process to remove impurities and sent to two filling stations on the farm where it can be pumped into trucks. That’s the plan for the next six months or so, but eventually the gas will funnel into a local gas line, Bahler said. 

“We do have a main pipeline coming down the street here and will be hooked into this, where we’re going to be feeding gas right back into the pipeline. Eversource is one that put the gas line in,” he said. 

The project is a three-way partnership with SJI Utilities of New Jersey, and a developer, REV LNG, a supplier and transporter of Liquid Natural Gas.  

“As a farmer, we don’t have the capital to put into it and the resources to work with the energy companies to sell it. So it’s a partnership where we have the manure, they handle a side of it, we handle a side of it, and then we all get the proceeds from it,” Bahler said. 

The investment used no state money or grants, he said. 

He said the technology started with taking the gas off of the manure and feeding it through a generator, like the anaerobic digester at Fort Hill Farm in Thompson, Conn.

“That gas is really rough, so the generators only last a couple of years because it’s really raw gas and it’s pretty nasty on the equipment,” he said. “So this is kind of taking it a step farther where really we have a mini refinery here taking that gas and turning it into renewable natural gas.”

He said Oakridge Farm’s digester produces enough gas to fill a “53-foot compressed gas tanker” every other day.

“If you want an equivalent, it can power about 800 cars worth of gas every single day,” he said. 

The methane odor from the manure is also greatly reduced, he said, because most of it is burned off in the refining process. Methane is a potent greenhouse gas that contributes to global warming and “a single cow produces between 154 to 264 pounds of methane gas per year,” according to the Environmental Protection Agency.

The farm’s 3,000 Holsteins are milked three times a day on a rotating carousel. (CT Examiner)

At a barn not far from the digester, cows were lining up to be milked on a rotating carousel that holds 72 heifers. 

“See how they’re entering on by themselves? they want to get milked, every 8 hours,” said Bahler.

Each cow wears a Fitbit on a necklace – a program the farm started about a year and a half ago –  that shows how many steps she takes a day, how much she eats and sleeps, monitors her ruminating and her stomach, and measures how much she eats. 

“It’s just another piece of technology to help us manage our herd to make sure the cows are healthy and happy all the time – that’s number one,” he said.

The information is monitored by computer and if there is a deviation, the farmer will receive a message to check the cow. 

“You can usually catch a health issue a couple of days before you’ll actually see a visual issue,” he said. 

The barn is “free range, free stall,” he said. 

“They lay down wherever they want. They can eat whenever they want. There’s access to food, water and beds at all times. They lay down for about 14 hours a day. And they eat about 14 meals a day,” he said. 

He said the farm includes 2,400 acres of corn grown to feed the cows, plus about 800 acres of grass. 

The dairy employees about 50 workers, plus about 10 or 15 more in the dairy’s delivery company called Modern Milkman. The majority of the milk goes to Guida’s Dairy in New Britain, and the farm produces some of its own products, including strawberry, coffee and chocolate milk.

He said the farm could continue as a dairy producer without needing the anaerobic digester, but the goal is to be the “farm of the future.” 

“Dairy in general, our goal is to be carbon neutral, the dairy industry wants to be carbon neutral by 2050, and we want to be part of the solution for becoming carbon neutral, and taking steps to get there,” he said. “From a financial portion of it, we’re going to get more revenue from the digester. So that’s a benefit.”

Bahler, 34, said his great-great-grandfather started the farm in 1890 and it’s majority family owned. He’s been working on the farm for about 10 years and has a construction background.

“I actually personally never wanted to be a farmer because my dad was a farmer and just never thought I wanted to be. But I came in more on the business side and it seemed like a huge opportunity in our location to produce safe and healthy food for our community and just be part of the solution,” he said. 

When asked about whether the farm would have a sixth generation of farmers, Bahler said he has two daughters, ages two and four, and that he hoped the farm would continue in a sustainable manner. 

“About the next generation, I hope there’s another 30 generations. It doesn’t have to have the same last name as mine, but we want to have farmers producing safe and healthy food and feeding the world,” he said. “I think how we do that in the future is going to be different than we’re doing it today, but we need to take steps to doing it cleaner, better and more efficient.”