Palm oil production has come under significant scrutiny from environmental groups in recent years due to the ongoing links to deforestation of land in the tropics to make way for new palm plantations. But according to new research, there may be another reason for concern when it comes to palm oil production.
Writing in the journal Nature Climate Change, US researchers show that the wastewater produced during the processing of palm oil is a significant source of heat-trapping methane in the atmosphere. Indeed, the methane released from a single palm oil wastewater lagoon during a year is roughly equivalent to the emissions from 22,000 vehicles, said the authors behind the study.
"This is a largely overlooked dimension of palm oil's environmental problems," commented Philip Taylor from the University of Colorado at Boulder, who led the study.
However, the researchers also present a possible solution: capturing the methane and using it as a renewable energy source.
"The industry has become a poster child for agriculture's downsides, but capturing wastewater methane leaks for energy would be a step in the right direction," said Taylor.
The global demand for palm oil has spiked in recent years as processed food manufacturers have sought to find an alternative to trans fats.
As demand increases, so does the land needed for products, meaning that for now at least the carbon footprint of cutting down forests to make way for palm plantations dwarfs the greenhouse gases coming from the wastewater lagoons. But the team noted that deforestation is expected to slow in the coming years as the focus shifts to more intensive agriculture on existing plantations.
However, emissions from wastewater lagoons will continue unabated as long as palm oil is produced, the researchers said.
Taylor and his team suggested that a large amount of the climate impact of the leaking methane could be mitigated by capturing the gas and using it to fuel power plants, noting that biogas technology has been used successfully for decades and can produce renewable electricity at a cost that's competitive with traditional fuels.
The team calculated that the amount of methane biogas that went uncollected from palm oil wastewater lagoons last year alone could have met a quarter of Malaysia's electricity needs.
Tapping into that unused fuel supply could yield both financial and environmental benefits, they said.
Capturing methane at wastewater lagoons could be encouraged by making it a requirement before palm oil products can be certified as sustainable, added Taylor and his colleagues – who noted that current sustainability certifications do not address wastewater emissions.
Source: Nature Climate Change
Volume 4, Pages 151–152, doi: 10.1038/nclimate2154
“Palm oil wastewater methane emissions and bioenergy potential”
Authors: Philip. G. Taylor, Teresa M. Bilinski, et al