Although cow dung has been used for thousands of years to create fertile soils, it also has another use as a fuel. In many countries from China to Kenya, Guatemala to India, cow dung is often dried and burnt as fuel for cooking. Now in India, small scale farmers are separating methane to be used for cooking appliances and the remaining dung is used as a rich fertiliser.
As technology has advanced in the West, bio-digesters are utilising dung more efficiently to produce biogas. This gas is rich in methane and provides a renewable and stable source of electricity.
The following cases show the direction of travel:
Denmark: Biomass has become an increasingly important energy source in Denmark over the last 25 years. Being a carbon neutral energy source, it has already helped make a significant contribution to the reduction of Danish carbon emissions. The conversion of more biomass at power stations will help Denmark reach its target of 30% renewable energy by 2020. Yet the potential of using biogas has so far been unexploited, especially in the form of livestock manure in the agriculture system. Denmark is well known for its farming industry; approximately 65% of the land is used for agriculture, emitting 18% of all greenhouse gases here, through methane and nitrogen. So farming has an important part to play in the transition to a fossil fuel free society. The Danish government now wants up to 50% of livestock manure to be made into this green energy supply.
USA: Fair Oaks Farm, in Indiana is at the front end of some interesting innovation. The farm harnesses the power of cow dung to run its barns, offices, cheese factory and gift shop. What takes this farm one step ahead of the others is its ability to power its 42 tractor trailers that deliver milk to nearby states with renewable gas that also comes from animal waste. “We’re self-sufficient and we’re lowering our carbon footprint” says Gary Corbett, Fair Oaks Farm CEO.
“We take the manure from the cows and put it into sealed digester vessels, the manure is heated to 100 degrees at which the bacteria produces methane and CO2, which is called biogas. The Biogas is cleaned to remove the CO2, using water and pressure to create biomethane, which is then odorized to create renewable natural gas” explains Mark Stoermann of AMP Americas, an energy company partnering with Fair Oaks Farm to create the fuel.
The cow power concept is also saving the farm millions of dollars a year.
“We were running all these diesel trucks and we began to look at the potential of replacing all that diesel with natural gas. Then we figured out how to create our own natural gas instead of buying the diesel, so it saves us a lot of money, lowers emissions and helps clean up air quality in the cities where the trucks deliver.
“In 2013, we will take personally 2-million gallons of diesel off the road that we used in 2011 to deliver our milk.” He adds: “ the biofuel burns cleanly so it’s better for the environment.
It’s a fuel source not only for the farms but for nearby towns as well. “One cow can power a home,” says Erin Fitzgerald, from The Innovation Center for US Dairy. And since the excess gas can be sold back to the grid “It’s a new source of revenue for dairy farmers” who have been struggling in recent years”, she says.
“Turning farm waste into fuel has amazing potential” says energy technology consultant Brian Dolrein. “I can imagine a time in the near future when homes and factories will be powered by it and our cars will be running on it. It could reduce our dependence on fossil fuels and oil”.
Although the above case studies are unlikely to demonstrate the highest level of animal welfare in practice, they do indicate a possible path of reducing our addiction to fossil fuels if both high welfare and technology were suitably integrated.