John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Waste-derived biogas could potentially power 138 million homes, say researchers.
Using the toilet today? In the future, that might be considered even more of a wasteful act, as fuel from human dung could have an annual value reaching into the billions of dollars.
That’s according to researchers at UN University’s Institute for Water, Environment, and Health, who just released a report on the potential of poop-derived energy. They say the world’s yearly excrement, rendered into biogas, could translate into the equivalent of $9.5 billion in natural gas. Such loads of methane-rich fuel would supposedly be able to power as many as 138 million homes—the number of households in all of Brazil, Ethiopia, and Indonesia.
Even if waste is only gathered from people who defecate in fields, ditches, and whatnot, the value could be significant, the researchers explain in a press release:
UN figures show that 2.4 billion people lack access to improved sanitation facilities and almost 1 billion people (about 60% of them in India) don’t use toilets at all, defecating instead in the open.
If the waste of only those practicing open defecation was targeted, the financial value of biogas potentially generated exceeds US$200 million per year and could reach as high as $376 million. The energy value would equal that of the fuel needed to generate electricity for 10 million to 18 million local households. Processing the residual faecal sludge, meanwhile, would yield the equivalent of 4.8 million to 8.5 million tonnes of charcoal to help power industrial furnaces, for example.
What’s that about “faecal sludge”? It’s but another form of poo power. Dehydrated, charred ordure contains energy much like coal and charcoal, but unlike the latter doesn’t require cutting down trees.
Such a “waste to wealth” philosophy could help places with few toilets deal with sanitation issues while also enriching local coffers. That’s not to ignore potential problems, including wastewater contaminated with chemicals not being suitable for fuel production, hesitation from loan-giving financial institutions, and the hard-to-overcome “ick” factor. After all, could you enjoy the rich, smoky taste of meat knowing it was grilled over fecal charcoal?
But the idea has enough promise to warrant future investigation, the researchers assert in their report: “Rather than treating our waste as a major liability, with proper controls in place, we can use it to build innovative and sustained financing for development while protecting health and improving our environment in the process.”