John Vrieze has a machine called a digester on his dairy farm that's used to turn manure into energy (Photo by Todd Melby)
Big dairy farms produce more than just milk. They also generate manure. Lots and lots
of it. That can be a problem for farmers and the environment. Todd Melby reports on a
technology that reduces manure and generates electricity:
Transcript
Big dairy farms produce more than just milk. They also generate manure. Lots and lots
of it. That can be a problem for farmers and the environment. Todd Melby reports on a
technology that reduces manure and generates electricity:
(sound of suckling cows)
I’m on a dairy farm with John Vrieze and his daughter Brittany.
Oh, and some cows too.
Vrieze is a frugal man. A couple of winters ago, he had a contest with his son to see who
could use the least electricity. Vrieze was willing to go to extreme measures.
His daughter Brittany tells the story this way:
Brittany Vrieze: “He’d shut his fridge off in the winter time. Just use the outdoors for his
fridge. He was definitely trying to keep the kilowatts down.”
Todd Melby: “So what did he do? He just kept his milk in the porch?”
Brittany Vrieze: “Yup.”
Todd Melby: “And kept his frozen stuff outside?”
Brittany Vrieze: “Yup. Yup.”
Today, Vrieze isn’t just trying to save energy. He’s trying to create it.
(sound of cow moos)
From cow dung.
He’s got 1,600 head of cattle at his place here in western Wisconsin. Those cows produce
milk that gets made into cheese. But they also produce about 50,000 gallons of manure
— every day.
Farmers are required to store that manure in a big pool-like structure called a lagoon.
John Vrieze covers his up with a giant tarp.
“It would blow up from the biogas. It would look like a great big balloon or like the
Metrodome, for folks in the Cities. It’s from the nature decomposition of the manure. It
creates biogas. We would have to take that gas out from underneath the cover and flare it
off, which got us to thinking that there has to be a better way to use that energy than just
to flare it off.”
So Vrieze bought a $1 million machine called a digester. And he had help from the
federal government. They paid for a quarter of it. The government is interested in these
things because they can turn manure into energy.
And it turns out — the reason it’s called a digester — is a farm thing.
“A cow has four stomachs. We call the digester really the fifth stomach. All the stuff that
comes out of the back of the cow we then put in that digester.”
So this “fifth stomach” produces energy. However, it’s not ready-to-use energy. To sell it
as natural gas, it has to be about 95% methane. The gas from the digester is only about
60% methane.
(sound of pipeline burn off)
Another option is to convert it to electricity. But in the U.S., electricity is cheap.
Todd Melby: “You tried to sell it to the electric company, but they didn’t want it.”
Brittany Vrieze: “They’re not offering us enough money. So …”
After all this investment by Vrieze and the federal government, some of the gas he
collects is just being burned off into the air.
But maybe not for long.
Vrieze wants to build a greenhouse right on his Wisconsin farm so he can grow
vegetables and herbs in the winter. He says he’ll power it with energy from the digester.
“So, instead of your produce coming from 2,000 miles away – from the central valley of
California – wouldn’t it be neat if it came from 45 miles away?”
Vrieze is planning to use the water from the cow manure for his vegetables and herbs in
his greenhouse. And he’s got a machine similar to ones used at wastewater treatment
plants to clean the manure water.
But even with the digester, there’s still leftover manure he has to deal with. But Vrieze
says the digester makes it more manageable.
(blowing sound)
Some of the dry manure is blown into a pile where it’s gathered up and used as bedding
for the cows. In the summer, it’s also used for another purpose.
“It’s just a clean version of manure. It stinks a little bit. Most of the stink has been taken
out of it. And we mix this with potting soil and it works great for the plants. So …”
That manure/potting soil mix is sold to gardeners in the city. It’s another way for Vrieze
to be frugal and environmental at the same time.
For The Environment Report, I’m Todd Melby.