Sustainable agriculture: methane to the rescue?

Summary

Among all agriculture by-products, methane is one of the most dangerous for the environment. Yet it is also a useful gas that, if managed properly, can even become socially and environmentally sustainable. Here’s how.

24Août.
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 If agriculture takes such a toll on the environment, it is mainly because of its greenhouse gas emissions. Or, to be more precise, the emissions caused by ruminants. There are microorganisms in every cow’s digestive system called anaerobic organisms, which “digest” organic matter and transform it into a gas that is released into the atmosphere through belching, flatulence and manure: methane. Methane is widely used around the world as a fuel (it is actually the main component of natural gas, which is used every day in our homes to cook or heat), but it is also a very powerful greenhouse gas: 23 times more powerful than carbon dioxide, in fact.

A cow produces 250 litres of methane per day.

This is comparable to the amount of daily pollution produced by a car. There are over 1.5 billion cows in the world, and this number is growing. As the world’s population increases, more and more cows are needed to produce milk and meat. Managing cows’ methane emissions is therefore a crucial challenge for sustainable farming. Luckily, there are ways to reduce these emissions, and there are also ways to put this gas to good use. Danone has been exploring two of these options for the past few years.

Reducing methane emissions

There is obviously a strong correlation between what cows eat and the amount of methane they produce. The methane production process, called methanogenesis that takes place in their stomachs is actually what allows them to eat grass. There is also a solid link between the amount of methane cows produce and the quality of their milk: the less methane they emit, the less saturated fatty acids their milk will have. Modifying dairy cattle feed can therefore have a positive impact on both protecting the atmosphere and improving milk quality. In light of these findings, Danone partnered up in 2008 with the INRA (National Institute for Agronomic Research) and the association Bleu Blanc Cœur, which promotes sustainable agriculture for better health through food. Together, they launched the Linus project in France. Its aim is to adjust dairy cattle diets on over 200 farms to modify both their milk and their methane emissions. So far, introducing flax seeds in their diets has made it possible to improve their health, increase their productivity,

improve the quality of their milk and reduce their methane emissions by 20 to 30%.

It is now possible to know in advance how much methane will be produced and thus to monitor this production. These results are now being scaled up and Linus is being expanded to other countries such as Spain and the United States. A new challenge lies ahead: finding other solutions that are more relevant than flax seeds and which fit the cultures and constraints of these countries.

Biogas for everyone

However, even with all the efforts in the world, there will always be methane…which is a good thing. If it is collected and used as a fuel, methane is an efficient source of energy that is much needed to supply households with the power they need for everyday life. In developing countries, providing access to this safe, clean and widely available resource is crucial to relieve families of the time-consuming (and often health-altering) search for energy. The way to do this is quite simple: collect manure and domestic organic waste, process it through a biodigester installed on-site and use the generated gas to power homes or farming activities. To put it simply, biodigesters replicate what happens inside cows’ digestive systems using bacteria that turn organic matter into what is known as biogas. As this gas is made up of 50 to 70% methane, the process is called methanization, or methanogenesis. It can then be used like any other energy source to cook, light or heat. As they are so simple to operate, biodigesters can easily be built at any cost and with a wide range of materials. It can thus be a cheap and simple method for producing energy and, as such, has been widely adopted in developing or emerging countries such as Brazil (a major investor in renewable energies, and thus a huge user of biodigesters), China (where rebuilding the 10,000 digesters destroyed in the 2008 earthquake in Sichuan was a priority for even the authorities), Vietnam, Tanzania, Cambodia (where a National Biodigesters Programme has been developed in partnership with the Netherlands Development Organisation), etc. In Indonesia,

Danone helped install 200 digesters in 2009 on 200 farms which produce 54,000 litres of milk a day.

They help limit methane emissions, improve environmental quality and provide farmers with a new source of energy for both their activity and for everyday life.

In these countries, biodigesters are often used as domestic appliances that allow people to supply their own homes with energy through the methanogenesis of their own organic waste. And there are many benefits – the Cambodian NBP (National Biodigesters Programme) goes so far as to say that biogas directly contributes to the achievement of four of the Millennium Development Goals (MDGs), because it helps lift people from extreme poverty, prevents women from being obliged to constantly look for new sources of energy, thus leaving time for other activities such as education, it prevents many diseases or infections caused by coal, wood or straw pollution inside homes, and ensures environmental sustainability.

But biodigesters can also provide industrial benefits. In Bangladesh, a system has been set up around the Grameen Danone factory in Bogra as part of a comprehensive, ambitious programme to make the factory self-sufficient through renewable energy. One biodigester,

the first of its kind in Bangladesh, was added to the waste water treatment station.

It is fed by the effluents generated by the Shoktidoi manufacturing process. Another one was also set up at the factory to degrade PLA (polylactic acid) residues. “The resulting biogas is used for the following purposes: lighting the plant’s outer walls using gas lamps, and cooking food in the plant canteen, using hot plates.” And biodigesters are not just the prerogative of developing countries: when Danone partnered up with Stonyfield in France and Stonyfield needed to build its first industrial water pre-treatment plant, the decision was made to install an anaerobic biogas digester. As of 2008, the plant has been energy self-sufficient.
There are simple, inexpensive and efficient ways to reduce methane production in agriculture and put the remaining amount to good use. One of the most powerful greenhouse gases can become incredibly useful for a more sustainable agriculture!