Battling Climate Change with Agricultural Waste

Climate change has triggered the creation of a variety of social enterprises in the past couple of years. Jason Aramburu’s re:char -- a fledgling renewable energy technology company that’s working out of a warehouse in a shared artist’s loft in Brooklyn, New York – is among the most innovative. “Right now, the concentration of CO2 in our atmosphere is at about 387 parts per million,” Aramburu, 24, told Justmeans in a recent interview. “Leading scientists like James Hansen [the head of NASA’s Goddard Institute for Space Studies] say that if we don’t get below 350 ppm in the next two or three decades, we’re going to see some of the really catastrophic effects of climate change – things like drought, flood, and famine.”

So which existing energy technologies can get us below 350? That’s a question Aramburu, a 2009 PopTech Fellow, asked himself when he was working in the clean coal tech lab at Princeton a few years ago. “I realized that clean coal is an oxymoron,” he said. “Just getting it out of the ground is dirty.” Nuclear, he says, is expensive and wind and other renewables won’t do anything to take carbon out of the air. “So I thought to myself, why don’t we take these technologies and apply them to a cleaner fuel like biomass and make energy – while sequestering carbon?”

After a couple of years of research, Aramburu and his team developed biochar -- a highly porous charcoal that Aramburu says is just like the carbon charcoal you find in your barbecue grill except that it’s made from organic waste, like woodchips, corn husks, peanut shells, or even chicken manure.

“In the traditional agricultural carbon cycle, plants take in CO2,” Aramburu says. “You harvest those plants for food and we’re left with biomass; farmers take that biomass and mulch it or compost it and eventually, the CO2 that those plants took in gets back into the atmosphere by decomposing. But if we really want to fight climate change, we have to short out the system. We take those plants, turn them into biochar and then bury that biochar in the soil, the soil from which it came.”

To test the idea, Aramburu and his team went to Brazil to research the Amazon basin. Some 1,500 years ago, indigenous farmers there would take their agricultural wastes, turn them into charcoal and bury the charcoal in the ground. “You can go to those sites now and see that carbon they took out of the atmosphere is still in the ground, 1500 years later,” he says. “To me, that was proof that this works.”

The indigenous farmers didn’t bury their charcoal wastes because they knew about climate change, Aramburu said. They did it to fertilize the rainforest’s nutrient-poor soil. Biochar contains high levels of nutrients vital for plant growth, like nitrogen, phosphate, and calcium. “We’re finding that in the developing world today, in a trial we just did in Cameroon involving maize plants, that adding biochar to the soil actually improves crop yields by 200 to 250 percent,” he says. Biochar also locks carbon dioxide away, possibly for thousands of years.

How does it work? Aramburu and his team built a biomass processor for about $15,000. The unit, in a process called pyrolysis, can produce about 25 kilowatts of energy just from waste, enough to power a village in Africa. It also can produce about 120 tons of biochar per year and sequester 430 tons of CO2 annually. The pyrolysis process yields hydrocarbons, which can be made into fuel.

Aramburu and team just completed a pilot demonstration in Cameroon proving the technology. Meanwhile, researchers at the University of Michigan are working with re-char to test a prototype based on Aramburu’s design, and a working prototype on a small farm in Norfolk, Connecticut processes waste wood from trees that were destroyed in an ice storm last winter. ARamburu says the Brooklyn location gets several requests per week from farmers, ranchers and vineyard owners from across the United States, as well as Mexico, Puerto Rico, and Canada.

Aramburu’s next goal is to roll out his re:char on three continents. “We want to show this technology is applicable in Africa, Latin America and places like the Midwest of the United States,” says Arumburu. “Our current goal is to get 100,000 tons of CO2 out of the air. From there, we want to roll it out across the globe. If we can get 2 billion tons of CO2 out per year, we can roll back emissions to pre-1982 levels in just 10 years. I was born in 1985, so for young people like me, if we can scale this, we can see a world that we’ve never experienced.”