Green Tech

An ancient technique to fertilize soil by creating charcoal from plant waste is being revived to tackle some of today's environmental problems.

The latest company to pursue manmade charcoal, called biochar, is Biochar Systems, which has developed a biochar-making machine that can be pulled by a pickup truck. Two customers--a North Carolina farm and the U.S. Bureau of Land Management--will be begin testing the units this fall.

The unit, called the Biochar 1000, is designed to convert woody biomass, such as agricultural or forestry waste, into biochar, a black, porous, and fine-grained charcoal that can be used as a fertilizer. It uses pyrolysis--slowly burning biomass in a low-oxygen chamber--to treat 1,000 pounds of biomass per hour, yielding 250 pounds of biochar.

The Biochar 1000 converts agricultural wastes to charcoal, which is then added to soil, a process that enriches soil and removes carbon from air.

(Credit: EcoTechnologies Group)

There still isn't a well established market for selling biochar, but there's growing interest among researchers in the process as a way to cut greenhouse gas concentrations. The United Nations has proposed classifying biochar as a carbon credit for sequestering carbon from the atmosphere.

When forestry or agricultural waste are converted into biochar and put into the soil, the carbon that would have been released through decomposition is held in the soil for hundreds or potentially thousands of years, say proponents.

A number of companies have formed to either create fertilizer or use modified machines to convert biomass into a liquid fuel such as methanol. The first U.S. biochar conference was held in Boulder, Colorado, two weeks ago, organized by the International Biochar Initiative industry group.

Tons of green waste
Biochar Systems, a joint venture created by BioChar Engineering and EcoTechnologies Group, has developed a mobile machine targeted at landowners or other organizations that generate a lot of "green waste," such as agricultural producers, nurseries, or land managers. The biochar can be used on-site as a soil amendment or moved and sold as a fertilizer, according to Fernando Migliassi, chief corporate development officer at EcoTechnologies Group.

The Bureau of Land Management will use one unit, which weighs 4,000 pounds and is 12 feet long, seven feet high, and five feet wide, to improve soil that has been damaged by mining, according to Biochar Systems. The North Carolina Farm Center for Innovation & Sustainability will use test a unit as well to see how agricultural waste can be converted into fertilizer.

The Biochar Systems Biochar 1000 costs $100,000 and is capable of turning out 1,000 tons of biochar a year.

Another unit will be tested by the Colorado State Forest Service to thin forests and treat the tons of wood infested by pine beetle into a soil amendment. Thinning forests manually is very expensive but the biochar machine could be a cheaper route.

"If this is feasible, it would allow us to manage a greater portion of forested lands that right now aren't cost effective," Joseph Duda, forest management supervisor for the Colorado State Forest Service told ClimateWire.

The U.S. produces 368 million tons of forest product waste a year and another 60 million tons a year of wood infested by the pine beetle, according to BioChar Engineering. Having a mobile unit reduces overall pollution as biomass doesn't need to be hauled for treatment at a centralized plant, according to the company.

But although it has potential to mitigate climate change, some people have warned against relying heavily on biochar as a carbon offset. The impact of biochar on land may have changed since the time thousands of years ago when people in Amazon region created charcoal, called terra preta.

"But despite its astounding potential, caution is warranted in implementing biochar on any sizeable scale. Though re-creating terra preta sounds simple, recent research suggests that modern-day soils may respond less well to the treatment and that the carbon may escape sooner than anticipated. On these questions alone, all of the evidence is not in," according to a recent editorial in the journal Nature Reports Climate Change.

A new idea for storing carbon dioxide underground using charcoal, or biochar, is being panned by organizations that oppose large-scale geoengineering projects.

The ETC Group on Monday published opposition to biochar from 147 small environmental and human rights organizations, calling the growing support for biochar a "dangerous new false solution to climate change."

Manmade coal produced by Carbonscape's Black Phantom machine.

(Credit: Carbonscape)

Making charcoal--also called agrichar and terra preta--from organic matter like trees through low-oxygen burning, or pyrolysis, can improve soil while keeping carbon dioxide out of the atmosphere for thousands of years, say backers.

A number of companies are developing methods for making biochar as a strategy to stabilize carbon dioxide levels in the atmopshere. One New Zealand company called Carbonscape is developing a system that uses industrial-size microwave machines to turn wood, trash, and even sewage into biochar.

Carbonscape claims that its machine, called the Black Phantom, will sequester more carbon underground that the carbon dioxide generated for running its machine.

The ETC Group's organizations do not appear opposed to biochar outright. But they are clearly wary of polluters relying heavily on using bichar carbon offsets as a way to comply with carbon regulations.

Some environmentalists are in favor of using charcoal to store carbon underground and improve soil for agriculture--Carbonscape, for example, has some well known climate experts on its board. The warning by the ETC Group, which points to biofuels as an example, is a reminder to proceed with caution and common sense in implementing climate technologies.

Manmade coal produced by Carbonscape's Black Phantom machine.

(Credit: Carbonscape)

A new machine dubbed the "Black Phantom" can turn biomass into manmade coal.

Carbonscape, a New Zealand-based start-up, describes its invention as an industrial-sized microwave that can cook plant waste, wood waste, and "even sewage" into coal.

Carbonscape also claims that the machine captures and stores more carbon than the amount of carbon generated by the electricity needed to power it for the process.

Why would anyone want to make more coal when humans are desperately trying to get out from under the carbon dioxide mess we've been making since the Industrial Revolution?

The invention combines two popular environmental efforts: using biochar for carbon capture and storage (CCS), and developing alternative fuel sources from biomass.

While there are issues to be worked out on carbon capture and storage (CSS), it's seen by energy utilities and governments as a possible tool in reducing greenhouse gas emissions. Biochar is coal made from biomass that can be buried in soil as a carbon sink or for use in farming, rather than letting decaying plants release carbon dioxide back into the atmosphere.

Biomass--agricultural and wood byproducts that can be used to make ethanol, or electricity directly--is considered by the EU, the U.S. and others as a possible answer to reducing oil dependence while providing a cleaner and more efficient way to produce and consume energy.

As reported by the Financial Times, Carbonscape's machine turns biomass into a kind of biochar to be stored underground.

Though it's unclear just how clean it would burn, Carbonscape's biochar can also be burned as fuel.

Whether or not the invention is scalable remains to be seen, but judging from who is involved Carbonscape's claims seem legit.

The company's board includes Nick Gerritsen, the director of Aquaflow Bionomic, one of the companies developing algae biodiesel; and Tim Flannery, former Harvard University professor and environmental activist known for his books "The Future Eaters" and "The Weather Makers."