Dairy Practices Sustainability by Generating Natural Gas to Power Fleet

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Dairy practices sustainability by generating natural gas to power fleet_1

Some of the 30,000 cows at Fair Oaks Farm use a rotary milking machine at the farm.

Posted: Dec. 12, 2013

Some visitors at Fair Oaks Farms are captivated by the birthing barn and the chance to see a calf welcomed into the world.

Others can’t forget the sight of 72 cows turning slowly on a rotary milking machine while many more wait patiently for their turn.

But with so much happening at the sprawling dairy and tourist attraction in Northwest Indiana, the most amazing thing may well be the hardest to see.

The dairy is turning the 1.5 million gallons of manure that its 30,000 cows produce each day into natural gas. The gas powers a fleet of 42 trucks with Cummins Westport natural gas engines that deliver milk around the clock to processing plants in Indiana, Kentucky and Tennessee.

“Part of running a dairy is dealing with the waste that comes out of the cows,” said Mark Stoermann, Director of Operations for AMP Americas, which partners with Fair Oaks to produce compressed natural gas, or CNG. “So as part of dealing with that waste, we’ve tried to find innovative ways to convert waste into energy.”

The United States Department of Energy says Fair Oaks is the largest natural gas fleet in the country using agricultural waste as its primary fuel source. The dairy estimates it is conserving about 2 million gallons of diesel fuel annually.




Mark Stoermann, Director of Operations, AMP Americas.








Stoermann says Fair Oaks’ focus on sustainability goes back to a decision made more than a decade ago to look at all that manure as an opportunity – not a burden.

Facing growing concern about the odor from its operations, the dairy began experimenting with anaerobic digestion as an alternative to the traditional disposal method of storing the manure in pits until conditions were right to apply it to area farm fields.

Stoermann, who has been overseeing projects at the farm since 2000, said when manure sits it decays and the odor becomes much worse.

“We are in a location very close to I-65 (an interstate highway in Indiana) with quite a few neighbors around and odor control was very much on the minds of the dairymen as they looked for advanced manure management techniques,” Stoermann said.

Fair Oaks has invested millions into a system of digesters to convert its manure into gas. The dairy’s central digester is a non-descript building on the outside that contains a complicated series of tanks and conveyor equipment to begin the process.

The gas is actually produced in back in a gray, rectangular tank about half the size of a football field and then piped to some silver towers nearby where it is readied for use.

While anaerobic digestion was hardly a new idea when Fair Oaks began pursuing it, few if any places were using it on such a large scale. So much of the farms’ work to produce its own natural gas has been by trial and error.

Dairy practices sustainability by generating natural gas to power fleet_3
A view of the farms central digester. Inside the building at right, the manure and sand are separated. Gas is produced in the long, gray tank at left.


Here’s how the Fair Oaks system works. The dairy uses sand for the cows’ bedding and three times a day while the cows are being milked the sand and manure are vacuumed up and delivered to a digester. Water is added to help separate the manure and sand. The sand is then collected, dried and reused.

The watered-down manure next goes into the large tank in back where natural organisms in the manure create gas. Carbon dioxide and hydrogen sulfide are removed by scrubbing the biogas with water, creating a final product that is around 98 percent natural gas.

Fair Oaks estimates any objectionable odors are reduced by about 95 percent.

The dairy has been fueling its trucks with natural gas for around two years.   About 80 percent of the gas it produces today is used by its fleet; the rest helps power Fair Oaks’ cheese factory and restaurant, the birthing barn and other parts of its operations.

Fair Oaks also sells some of the gas back to the gas utility that serves Northwest Indiana.

If you’ve spent any time on Interstate 65 between Chicago and Louisville, Ky., recently, there’s a pretty good chance you’ve seen the red Kenworth T440 tractors and silver tankers that make up the Fair Oaks fleet.

The dairy leases the cabs from Palmer Trucks, a leader in heavy duty trucking using alternative fuels, and the tankers are from Ruan Transportation Management Systems, a national trucking company based in Des Moines, Iowa, that puts a major emphasis on environmental stewardship.

“Our fleet is really, really pressed hard,” Stoermann said. “We are running 42 trucks, delivering 53 loads of milk a day. Most trucks average 720 miles a day so each truck is averaging over 250, 000 miles a year.”

Dairy practices sustainability by generating natural gas to power fleet_4
One of the farms’ trucks fuels up at the natural gas station on the property.



Fair Oaks has been using Cummins’ Westport’s 8.9 liter ISL G natural gas engine, knowing the engine was undersized for pulling payloads of close to 80,000 pounds when the tankers are full of milk.

In the fall of 2013, it began converting its fleet to Cummins Westport’s new ISX12 G engine, a 12 liter engine designed for the kind of demands the dairy is putting on its fleet.

Because of a shortage of fueling stations around the country, natural gas engines are most widely used by regional fleets like Fair Oaks. Drivers on regional routes can typically return home at the end of the day to refill or they have access to natural gas fueling stations along regular routes. Fair Oaks, for example, has opened its own refueling station near the Indiana-Kentucky border in addition to its station at the dairy.

Bigger engines like the ISX 12 G are needed to pull heavier loads over longer distances.

“It’s pretty exciting to see Fair Oaks use the fuel not only for their trucks but also for power generation at their site,” said Kendra Eads, a Cummins engineer who has toured the dairy’s operations. “It’s a real practical way of looking at sustainability that you don’t necessarily get a feel for when you read something in the newspaper about sustainability and renewable resources.”

“It will be interesting to see over the next few years how the infrastructure of the fueling stations grows,” added Eads, who has been working on the development of larger natural gas engines at Cummins. “I think as the number of fueling stations grow, people will feel more comfortable with choosing natural gas as the solution that works for them.”


Fair Oaks wants to demonstrate that converting waste to energy is a viable option for other dairies and similar businesses that generate a waste product that can be converted into fuel.

Stoermann said the central digester at Fair Oaks will have about a 10-year payback, although he points out the return for the dairy’s neighbors was immediate in the form of improved odor control

“There are a lot of industries in the United States right now that are looking at CNG and there are a lot of other industries that have waste streams that could be used in anaerobic digestion,” Stoermann said. “So yes, the simple answer to your question is this is a model that can be reproduced all over the United States.”


1.5 million

Gallons of manure the cows at Fair Oaks’ 11 dairies in Northwest Indiana collectively produce every day.


Gallons of milk the cows at Fair Oaks produce daily.


Cows at Fair Oaks.


Percent odor is reduced by the Fair Oaks digesters.


Number of times cows have to be milked over a 24-hour period.


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