How Dairy Methane Becomes Renewable Energy

When people think about dairy farms, they often picture cows grazing in open fields or milk being poured into cartons. But there’s something else that comes from cows—and it’s a big deal for the environment: methane. Methane is a powerful greenhouse gas, and dairy farms produce a lot of it. The good news? That methane can be turned into clean, renewable energy.

At Calgren, we take something that’s usually seen as a problem and turn it into a solution. Here’s how we turn methane from cows into renewable natural gas (RNG) that can heat homes, fuel trucks, and help fight climate change.

What Is Dairy Methane?

Cows release methane in two main ways: through their digestion (called enteric emissions) and from their manure. When manure sits out in open air, especially in large pits or lagoons, it breaks down and releases methane into the atmosphere.

Methane is over 20 times more powerful than carbon dioxide at trapping heat. That means even small amounts can make a big impact on the planet. But if we capture it before it escapes, we can put it to good use.

Step One: Capturing the Methane with Anaerobic Digestion

To stop methane from escaping into the air, Calgren uses a process called anaerobic digestion. That’s just a fancy way of saying we break down manure in a digester without any oxygen.

Think of the digester like a big, sealed balloon. Inside, tiny microbes go to work, breaking down the waste. As they do, they release biogas—mostly made up of methane and carbon dioxide.

There are a few different types of digesters. Some are covered lagoons, which are large ponds with a cover to trap the gas. Others, like plug-flow tanks, are long and narrow systems that keep the waste moving through slowly, giving microbes time to work. No matter the type, the goal is the same: capture as much methane as possible.

Step Three: Using RNG in Everyday Life

After it’s cleaned and pressurized, Calgren RNG is actively injected into the utility natural gas pipeline. While renewable natural gas can serve various end uses, Calgren RNG is purposefully designated for use as vehicle fuel.

Some of the RNG Calgren helps produce is used for heating or electricity. Some fuel buses and trucks that would normally run on diesel. Because it comes from a renewable source and helps prevent methane from escaping into the atmosphere, this type of fuel is considered carbon-negative—it actually reduces greenhouse gases rather than adding more.

Calgren owns and operates a cluster of digesters across local dairy farms, making it possible to produce large amounts of RNG from one central location. This teamwork between farms and technology makes a big difference.

Why This Matters for the Future

Turning dairy methane into RNG does more than help the planet. It also helps farmers by giving them a new source of income. Instead of just dealing with manure as a waste product, they can turn it into something valuable.

There are also growing incentives and grants for these kinds of renewable energy projects. Governments are pushing for cleaner energy, and programs that support RNG are expanding. Calgren is looking ahead and exploring ways to use the same technology on other types of waste, like food scraps and crop leftovers.

A Cleaner Future, One Cow at a Time

Dairy methane might seem like a problem—but at Calgren, we see it as an opportunity. By capturing and converting it into renewable natural gas, we’re reducing emissions, creating clean energy, and supporting local communities.