“These calculations show that biochar can play a significant role in the solution for the planet’s climate change challenge,” said study co-author Jim Amonette, a soil chemist at the Department of Energy’s Pacific Northwest National Laboratory. “Biochar offers one of the few ways we can create power while decreasing carbon dioxide levels in the atmosphere. And it improves food production in the world’s poorest regions by increasing soil fertility. It’s an amazing tool.”
The study is the most thorough and comprehensive analysis to date on the global potential of biochar. The carbon-packed substance was first suggested as a way to counteract climate change in 1993. Scientists and policymakers have given it increasing attention in the past few years. The study was conducted by Dominic Woolf and Alayne Street-Perrott of Swansea University in Wales, U.K., Johannes Lehmann of Cornell University in Ithaca, N.Y., and Stephen Joseph of the University of New South Wales, Australia, and Amonette.
Biochar is made by decomposing biomass like plants, wood and other organic materials at high temperature in a process called slow pyrolysis. Normally, biomass breaks down and releases its carbon into the atmosphere within a decade or two. But biochar is more stable and can hold onto its carbon for hundreds or even thousands of years, keeping greenhouse gases like carbon dioxide out of the air longer. Other biochar benefits include: improving soils by increasing their ability to retain water and nutrients; decreasing nitrous oxide and methane emissions from the soil into which it is tilled; and, during the slow pyrolysis process, producing some bio-based gas and oil that can offset emissions from fossil fuels.
Making biochar sustainably requires heating mostly residual biomass with modern technologies that recover energy created during biochar’s production and eliminate the emissions of methane and nitrous oxide, the study also noted.
Crunching numbers and biomass
For their study, the researchers looked to the world’s sources of biomass that aren’t already being used by humans as food. For example, they considered the world’s supply of corn leaves and stalks, rice husks, livestock manure and yard trimmings, to name a few. The researchers then calculated the carbon content of that biomass and how much of each source could realistically be used for biochar production.
With this information, they developed a mathematical model that could account for three possible scenarios. In one, the maximum possible amount of biochar was made by using all sustainably available biomass. Another scenario involved a minimal amount of biomass being converted into biochar, while the third offered a middle course. The maximum scenario required significant changes to the way the entire planet manages biomass, while the minimal scenario limited biochar production to using biomass residues and wastes that are readily available with few changes to current practices.Amonette and his colleagues found that the maximum scenario could offset up to the equivalent of 1.8 petagrams – or 1.8 billion metric tons - of carbon emissions annually and a total of 130 billion metric tons throughout in the first 100 years. Avoided emissions include the greenhouse gases carbon dioxide, methane and nitrous oxide. The estimated annual maximum offset is 12 percent of the 15.4 billion metric tons of greenhouse gas emissions that human activity adds to the atmosphere each year. Researchers also calculated that the minimal scenario could sequester just under 1 billion metric tons annually and 65 billion metric tons during the same period.
But to achieve any of these offsets is no small task, Amonette noted.
“This can’t be accomplished with half-hearted measures,” Amonette said. “Using biochar to reduce greenhouse gas emissions at these levels is an ambitious project that requires significant commitments from the general public and government. We will need to change the way we value the carbon in biomass.”
Experiencing the full benefits of biochar will take time. The researchers’ model shows it will take several decades to ramp up biochar production to its maximum possible level. Greenhouse gas offsets would continue past the century mark, but Amonette and colleagues just calculated for the first 100 years.
Biochar and bioenergy work together
Instead of making biochar, biomass can also be burned to produce bioenergy from heat. Researchers found that burning the same amount of biomass used in their maximum biochar scenario would offset 107 billion metric tons of carbon emissions during the first century. The bioenergy offset, while substantial, was 23 metric tons less than the offset from biochar. Researchers attributed this difference to a positive feedback from the addition of biochar to soils. By improving soil conditions, biochar increases plant growth and therefore creates more biomass for biochar productions. Adding biochar to soils can also decrease nitrous oxide and methane emissions that are naturally released from soil.
However, Amonette and his co-authors wrote that a flexible approach including the production of biochar in some areas and bioenergy in others would create optimal greenhouse gas offsets. Their study showed that biochar would be most beneficial if it were tilled into the planet’s poorest soils, such as those in the tropics and the Southeastern United States.
Those soils, which have lost their ability to hold onto nutrients during thousands of years of weathering, would become more fertile with the extra water and nutrients the biochar would help retain. Richer soils would increase the crop and biomass growth – and future biochar sources – in those areas. Adding biochar to the most infertile cropland would offset greenhouse gases by 60 percent more than if bioenergy were made using the same amount of biomass from that location, the researchers found.
On the other hand, the authors wrote that bioenergy production could be better suited for areas that already have rich soils - such as the Midwest - and that also rely on coal for energy. Their analysis showed that bioenergy production on fertile soils would offset the greenhouse gas emissions of coal-fired power plants by 16 to 22 percent more than biochar in the same situation.
Plantations need not apply
The study also shows how sustainable practices can make the biochar that creates these offsets.
“The scientific community has been split on biochar,” Amonette acknowledged. “Some think it’ll ruin biodiversity and require large biomass plantations. But our research shows that won’t be the case if the right approach is taken.”
The authors’ estimates of avoided emissions were developed by assuming no agricultural or previously unmanaged lands will be converted for biomass crop production. Other sustainability criteria included leaving enough biomass residue on the soil to prevent erosion, not using crop residues currently eaten by livestock, not adding biochar made from treated building materials to agricultural soils and requiring that only modern pyrolysis technologies – those that fully recover energy released during the process and eliminate soot, methane and nitrous oxide emissions – be used for biochar production.
“Roughly half of biochar’s climate-mitigation potential is due to its carbon storage abilities,” Amonette said. “The rest depends on the efficient recovery of the energy created during pyrolysis and the positive feedback achieved when biochar is added to soil. All of these are needed for biochar to reach its full sustainable potential.”
The study was funded by the Department of Energy’s Office of Science, DOE’s Office of Fossil Energy, the Cooperative State Research Service of the Department of Agriculture, the New York State Energy Research and Development Authority, the United Kingdom’s Natural Environment Research Council (NERC) and Economic and Social Research Council (ESRC), and VenEarth Group LLC.
REFERENCE: Dominic Woolf, James E. Amonette, F. Alayne Street-Perrott, Johannes Lehmann, Stephen Joseph. “Sustainable biochar to mitigate global climate change,” Nature Communications, Aug. 10, 2010. http://www.nature.com/ncomms/journal/v1/n4/full/ncomms1053.html.
Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, the environment and national security. PNNL employs 4,700 staff, has an annual budget of nearly $1.1 billion, and has been managed by Ohio-based Battelle since the lab's inception in 1965. Follow PNNL on Facebook, LinkedIn and Twitter.
Franny White | Newswise Science News
Further reports about: > Heat Blanket > Nature Immunology > PNNL > Street-Perrott > Wales > bioenergy production > carbon dioxide > carbon emissions > coal-fired power plant > energy production > gas emission > greenhouse gas > greenhouse gas emission > methane emissions > nitrous oxide > organic material > power plant
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy