The Australian Wine Research Institute (AWRI) is investigating ways to use grape pomace to reduce livestock methane emissions – thought to be a major cause of global warming.
A cow releases up to 120kg of methane per year (Photo: Wiki)
Previous studies have shown that grape pomace – a by-product of crushing grapes for wine production – can reduce methane production in the digestive system of sheep and cattle.
It’s estimated that around 13 million tonnes of grape pomace are created by the wine industry each year.
The AWRI is now investigating ways of turning pomace into stock feed to reduce emissions from the animals, Australian broadcaster ABC has reported.
Senior winemaker at the AWRI, Geoff Cowey, said the research had been prompted by the livestock industry’s wish to reduce its environmental impact.
In the year to March 2015, agriculture accounted for 15% of Australia’s greenhouse gas emissions, according to government data. The UN estimates that agriculture accounts for nearly one-fifth of greenhouse gas emissions worldwide.
Cowey explained that tannins and fatty acids in grapes made digestion in the animals’ rumen (their first stomach) more efficient.
The AWRI project involves developing the most efficient way to dry and transport pomace, and limit the potential for mould to grow on it.
“The most important value of grape marc [pomace] is that it can be potentially cheaper than things like grains and other feeds,” Cowey told ABC.
“You don’t want to process it too much where it suddenly becomes quite expensive, so you are spending more money to make something in a reuse fashion. So it’s about smarter use.”
The AWRI research is based on a previous Australian study, conducted between 2009 and 2012, which found that grape pomace significantly reduces livestock methane emissions.
Though methane occurs in lower concentrations than carbon dioxide (CO2), it produces 23 times more Global Warming Potential, according to the UN Food and Agriculture organisation. The gas accounts for 20% of the ‘enhanced greenhouse effect’.
Methane is generated naturally by bacteria that break down organic matter, it is found in the guts of termites and other animals and in natural gas deposits.
At present, about two-thirds of global methane comes from man-made sources, such as the burning of fossil fuel, the accidental release during drilling for natural gas or from livestock.