Trucks arrive at the brown hill like an army of ants, then crawl up, whipping dust into the sky before dumping trash unceremoniously at the top. What happens later sets the Buenos Aires landfill apart from most others in South America: Planet-warming methane leaking from the trash is turned into power.
Norte III — a 1,200-acre site whose garbage hills draw the eye in table-flat Buenos Aires — recently activated a new power station that runs on gas piped from under the hill through tree-trunk-sized black tubes. The five megawatts generated by landfill operator Ceamse may be enough to run only several thousand homes, but they represent a victory in a global campaign against methane that’s gathering momentum at the United Nations climate summit in Scotland.
Methane rising from the hill known as module D became a global hot spot, with rotting food creating a plume so dense that it could be seen from space, according to a June image from geoanalytics firm GHGSat.
“When I was a teenager, Ceamse was a disgusting place; you’d dread even having to pass by,” said Carla Coluccio Leskow, an Argentine trash consultant. “Today, it’s a model for waste management.”
The success comes even as greenhouse gases spew from a gamut of industrial and agricultural sources — and as leaders at the Scotland summit known as COP26 make curbing emissions of methane a key part of the agenda. Methane is one of the most powerful greenhouse gases, with more than 80 times the warming impact of carbon dioxide in the short term.
Landfill gas accounts for a fifth of methane releases, according to a report this year by the Climate & Clean Air Coalition and the UN Environment Programme. Countries including Mexico, France and Thailand are increasingly capturing it to feed power production, and in the United States around 500 trash dumps produce energy. As part of the redoubled effort to contain leaks, the US is aiming to capture 70 percent of landfill gas emissions, US President Joe Biden said at COP26.
It takes less than a year from when organic trash — food — arrives at a dump for bacteria to digest it and create methane. Wells and blowers then extract it to produce electricity, vehicle fuel or even pipeline gas. The technique has been used reliably for decades.
In South America, the process has seen fitful success, and Buenos Aires is among the region’s clearest examples of sustained progress. “Argentina leads the way together with Brazil and Chile,” said Marcelo Rosso, Ceamse’s head of new technologies and environmental control, during a recent visit to Norte III, which receives about 85% of Buenos Aires’s waste.
Landfill gas power projects often need help — such as through a carbon credit program — to make financial sense, according to the U.S. Environmental Protection Agency. “The global trend outside of the US has been a decrease in the number of landfill gas projects absent strong financial incentives,” Tim Carroll, the EPA’s deputy press secretary, said in an email.
Argentina finds it especially difficult to attract finance as it grapples with poor business conditions that have choked off funds. The country is likely to see a slew of clean energy projects stall next year as its government is more focused on producing shale gas in Patagonia than trying to revive renewables.
Failure to rein in methane could be felt hard in Argentina, where climate change is already taking a toll. Droughts in recent years have parched farmland in the powerhouse crop producer and the main shipping outlet, the Paraná River, is so shallow that vessels have trouble loading. In Buenos Aires itself, temperatures soared to more than 97 degrees Fahrenheit (36 degrees Celsius) in the last week of October, a record for the month.
“Our leaders make nice speeches but there’s no coherence when it comes to delivering on action to meet commitments,” said Enrique Maurtua, a climate policy adviser at FARN, an environmental and sustainability group in Buenos Aires.
A case in point is President Alberto Fernández’s November 2 address at COP26, where he said he supported US-led efforts to tackle methane releases and would promote technologies at home to capture the gas. But just days earlier, Argentina’s Agriculture Ministry published a joint document with farm groups implying that it planned to do nothing about large emissions from cattle ranching.
Against that backdrop, Ceamse’s efforts stand out. It began looking into methane capture in the late 1990s, around the time that world leaders were signing the Kyoto Protocol to commit to reducing emissions. Ceamse — jointly owned by Buenos Aires City and Province — finally got its first landfill plants running in 2012. Under the presidency of Mauricio Macri, whose market-friendly policies allowed Argentina to sprint toward its renewables goals, the company won more contracts, including the module D plant at Norte III.
The hill let off methane for several months while Ceamse was getting the plant ready, but now gas is getting piped out of three quarters of the trash. The rest can’t be degasified yet because trucks continue to deliver 13,000 metric tons a day of waste there.
There’s a catch to landfill gas power. Only 40 percent of the methane can be captured and piped to plants, said Gerardo Canales, director of ImplementaSur, a climate consultancy in Chile that’s advised the national and municipal governments. And when methane is burned it produces carbon dioxide, though emissions fall overall, Canales said.
Ultimately, environmentalists envisage a different solution — generating far less methane at landfills altogether.
That requires a behavioural shift. Rather than throwing away food, which composes about half the garbage Latin Americans produce, residents would separate it to make compost. While European cities do a much better job of that than Buenos Aires or Santiago de Chile, Ceamse is able to fish some food waste out from Norte III and compost it.
“In an ideal world we’d put the biogas plants at landfills out of business,” said Jonathan Banks, who tracks super pollutants at the Clean Air Task Force. “But today it’s a two-pronged approach.”
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by Jonathan Gilbert, Bloomberg