Stories tagged methane

New fossil evidence indicates that the ancestors of modern kangaroos walked on four legs, had fangs and climbed trees -- a sobering thought. Meanwhile, scientists studying marsupial flatulence have discovered that kangaroo gas contains no methane, and thus does not contribute to greenhouse gasses. A spokesman for kangaroos said he was glad no kangaroos were involved in changing the Earth's climate.


Excuse me: British scientists are looking for less gassy diet options for cows to reduce their burps. Cows belch 25 to 50 gallons of methane a day, which contributes to global warming. (flickr photo courtesy of Denmar)
Excuse me: British scientists are looking for less gassy diet options for cows to reduce their burps. Cows belch 25 to 50 gallons of methane a day, which contributes to global warming. (flickr photo courtesy of Denmar)
Don’t you just hate it when cows burp?

Scientists working on global warming and climate change hate it just as much as we do and are doing something about it. They’re working on developing new diets for cows that will cut back on their burps and the amount of methane they’re expelling into the atmosphere.

The average cow belches out 25 to 50 gallons of methane each day. Methane is a greenhouse gas that contributes to the growing carbon dioxide levels in the atmosphere that fuel global warming.

So what’s a polite, green-friendly cow to eat these days and reduce global warming? Scientists in Great Britain are proposing simpler digestibles like legumes – such as clover and alfalfa – could reduce cows’ belching significantly. The researchers also say that more grasses could be bred that would be easier for cows to process.

There’s good news for the very impolite cows. The scientists have also determined that methane is released into the air through cow burps, not the gas emissions they make from the other end of their body. They don’t have to strike baked beans from their diet!


Cow Power: photo by Art Oglesby,    Cow manure can produce electricity.
Cow Power: photo by Art Oglesby, Cow manure can produce electricity.

What comes out of the back end of a cow?

Milk and manure. The cows at the Audet family's Blue Spruce Farm make almost 9,000 gallons of milk a day — and about 35,000 gallons of manure. With the help of their power company, Central Vermont Public Service Corp., the Audets have devised a way to extract methane from the manure and pipe it to a generator. They make enough electricity to power 300 to 400 average Vermont homes.

How can electricity be made from cow manure?

If cow manure is pushed into a long, narrow tank and held around 100 degrees, in about 20 days bacteria will digest the manure into methane gas and a liquid slurry. The methane can run an engine and generator to make electricity. A dry, odor-free, fluffy brown substance that is used as bedding for the cows can also be extracted. The remaining liquid contains enough nutrients that it can be used as fertilizer for the farm's feed crops.

Do farms in Minnesota make electricity from manure?

Since late 1999, the Haubenschild farm has been converting their cow manure into electricity. At first they, too, digested manure producing methane which fueled a generator to produce electricity. Then, on Jan. 27, 2005, for the first time anywhere in the world, the methane was fed into a fuel cell.
A fuel cell is like a battery. A chemical reaction generates the electricity. It is totally quiet, and the only waste product is clean water. Haubenschild said it costs 5.1 cents per kilowatt hour to produce electricity from the fuel cell and Great River Energy will buy the surplus electricity from the fuel cell for four cents per KWH. If Minnesota power companies can create a progam similar to Vermont's Cow power program, customers willing to pay a couple extra cents per KWH would allow farmers to make money instead of losing money.

What are the benefits of anaerobic digestion?

    Reduced odor and greenhouse gas emissions
    Fewer pathogens in the digested product
    Nutrient rich effluent to apply to crops
    Electricity to use and to sell
    Possible sale of separated solids as a garden amendment
    Good manure management
    Pay back on the investment

Read more about Cow power
Biosystems and Agricultural Engineering Department, Univ. of MN.
Princeton Union-Eagle
Pioneer Press
FAQ about CVPS Cow Power


Scientists at the Max Plank Institute in Germany have discovered that living trees are a major source of methane in the Earth's atmosphere. Methane is a major "greenhouse gas," implicated in global warming.

Trees and sun: Trees and sun

Before this study, scientists thought plants only released small amounts of methane, and then only when they decomposed (as in swamps). The new research shows that plants release methane throughout their lives, and in large amounts—up to 30% or more of the planet's total methane production may come from plants.

This forces us to re-think environmental efforts. Strategies for dealing with climate change, such as the Kyoto Protocols, often call for planting more trees. And it's true that trees do take a lot of carbon dioxide out of the atmosphere—the most prevalent greenhouse gas. But now it turns out trees also release methane, so their benefit is not quite as great as once thought.


With all the doom-and-gloom stories in the news about how we might soon run out of space in landfills and fossil fuels, it's nice to read about an innovation that uses landfills to provide energy.

Methane forms when organic waste decomposes in the absence of oxygen, as in landfills. At a few landfills, the methane is collected and used to power vehicles or to heat nearby buildings. But most of it goes to waste. Landfill operators burn it off to prevent dangerous build-ups of the flammable gas. Burning off the methane not only wastes the potential fuel, but it also pumps pollutants into the atmosphere. In Europe alone, landfills have the potential to generate as much as 94 billion cubic meters of methane per year.

Why don't we use the methane from more landfills? Well, people usually extract it by sinking pipes into the landfill and sucking the gas out. But if the landfill isn't airtight, sucking out the methane also sucks in air. The oxygen is not only difficult to separate from the methane, but it also slows down methane production inside the landfill. So, until now, the only landfills where methane extraction has been viable have been those large and deep enough to restrict the entry of air.

But Viktor Popov, at the Wessex Institute of Technology, has figured out some simple modifications that allow methane extraction from any landfill. His solution is to cover the landfill with a membrane that prevents air from getting in. The membrane consists of three layers: a middle, permeable layer sandwiched between two mostly impermeable layers. Popov continuously pumps carbon dioxide (which can itself be extracted from the gasses in the landfill) into the middle layer so that the CO2 is slightly above atmospheric pressure. This creates a barrier that prevents air being drawn into the landfill—as the methane is sucked out of the ground, CO2 gets sucked into it from the membrane.

You can see a diagram of how this works

A landfill can continue to be a source of energy long after it's closed to new garbage. Decomposition can keep going underground, producing methane, for 15 to 20 years.

Are you interested in new sources of energy? Would you be willing to pay more for "green energy" if the option were available to you?