Biochar is undergoing extensive research and development globally as a promising solution to a host of environmental challenges. Its proven ability to increase soil fertility and thus contribute to food security, allow for energy recovery, and purify water resources, all while mitigating climate change through carbon sequestration, makes biochar an extremely promising element in the quest for sustainability. Although the concept of biochar is still in its infancy in terms of production and application in South Africa, understanding and identifying its potential is important heading into an uncertain environmental future.
WHAT IS BIOCHAR AND HOW IS IT PRODUCED?
Biochar is charcoal made from organic matter that can be used for various applications, most notably as an effective soil amendment. Like most charcoal, biochar is made from biomass via pyrolysis, which is the thermochemical decomposition of organic material at high temperatures in a low (or zero) oxygen environment. Any organic matter, including wood, agricultural waste such as manure and crop residues or selected household solid waste, can be used to produce biochar. Once complete, the pyrolysis process creates a fine-grained, highly porous charcoal that has a myriad of benefits. Once this charcoal is layered onto the ground, it is referred to as biochar.
AGRICULTURE, FOOD SECURITY AND ENERGY GENERATION
Biochar’s largest contribution will likely be seen in the agricultural sector. Once produced, biochar can be spread across fields and be incorporated into the top layer of soil, where it provides many benefits. First and foremost, biochar increases crop yields as it acts as a soil amendment, which is defined as any material that is added to the soil to improve its physical qualities, especially its ability to store water and microbes beneficial for plants. The most common soil amendment used today is compost, but biochar reportedly has many additional advantages.
Due to its extremely porous nature, biochar allows soil to retain more moisture, helping plants through challenging periods of drought. This reserve of water could alleviate future pressures on (rural and urban) farmers. Biochar also replenishes exhausted or overused soils with organic carbon and fosters the growth of soil microbes essential for nutrient absorption. “In a carbon-constrained world, anyone with quality carbon is king,” says Kevin James, founder of GCX Africa. Biochar also helps prevent fertiliser run-off and leeching by retaining and storing the nutrients already present in the soil. This ultimately reduces the need for excess fertilisers, which in turn reduces agricultural pollution to the surrounding environment. All of these benefits will allow for increased food security in future, and for more sustainable farming methods. Although biochar isn’t used commercially in electricity generation, in theory it could be. The process of producing biochar generates the gases needed to generate electricity, with biochar merely being the by-product. Generating electricity with organic matter through pyrolysis is commonly referred to as biomass electricity generation. While biochar itself can be directly substituted for any application that uses coal, this is considered an inefficient use of the resource.
BIOCHAR AS A CLIMATE CHANGE MITIGATION MEASURE
Biochar’s potential as a climate change mitigation measure is one of the main reasons the global biochar industry is growing rapidly. Several studies, including an extensive research report by the Department of Environmental Affairs (DEA) on biochar have clearly shown its great potential to help mitigate climate change via carbon sequestration (ability to absorb carbon). When biochar is created from biomass, about 50% of the biomass’ carbon is stored in the by-product as opposed to being released into the atmosphere. This removes the carbon from the active cycle. As carbon in charcoal is largely inert, it shows a relative lack of reactivity both chemically and biologically, which means it is more resistant to decomposition over time. Indirectly, biochar, when applied to soil, significantly enhances plant growth, which naturally absorbs further carbon dioxide from the atmosphere. Although many organic and inorganic substances contain carbon atoms, it is believed only diamonds could provide a more permanent solution to carbon storage than charcoal. Studies have found charcoal particles as old as 400 million years in sediment layers from wild res that occurred when plant life first developed on Earth. Biochar therefore offers an excellent opportunity to prevent excess carbon dioxide from entering the atmosphere and stores it in a virtually permanent and environmentally beneficial way. Overall, these benefits make the biochar process carbon negative as long as biomass production is managed in a sustainable manner. When producing electricity with biomass, the important difference is that fossil fuels, such as coal, contain carbon that was sequestered thousands or even millions of years ago. When these resources are burned they cannot be replenished. This makes fossil fuels a finite resource and different to organic waste, which can be managed sustainably to provide a continuous fuel source and a system for re-absorbing carbon dioxide that is released through burning.
THE SOUTH AFRICAN BIOCHAR INDUSTRY
According to James, the biochar industry in South Africa has moved relatively slowly to date. This, he believes, is a problem at both the demand and supply side. Locally, the Berg River Improvement Project in the Western Cape included a biochar component. Alien vegetation growing in the watershed area, which sucked up much of the water before it reached the river, was cut down and the biomass was used to produce biochar. Jason Mingo, task manager of the Berg River Improvement Project, says: “An important reason no further action has been taken is partly because of a lack of demand for such a product, as we have access to cheaper alternatives.” These cheaper alternatives (fertilisers) are effective at increasing crop yields but come with their own significant environmental concerns. A lack of education also poses a challenge. Many farmers are simply unaware of the benefits of using biochar as a soil amendment. There is a lack of urgency to inform and educate farmers on how to produce and apply biochar themselves. This must be addressed to increase demand. On the supply side, there are too few companies in South Africa that provide commercial biochar, or the technology necessary to produce it. At present, there is only one supplier of commercially available small-scale biochar production units in South Africa – Vuthisa Technologies. The equipment is generally expensive, and cost-effective mobile biochar producing units are difficult to source. A major challenge experienced during the biochar component of the Berg River Improvement Project was the cost of transporting the biochar. This could have been reduced significantly if mobile units had been available. According to the DEA report, if the biochar industry in South Africa is to become commercially viable on a scale that can have significant sequestration and yield-enhancing potential, a regulatory framework will be required to support biochar production. This would include favourable government policies and subsidy arrangements. The advantage of technology commercialisation is that licences, standards and approval assessments can be done for the technology as a whole, rather than for individual installations, which is where most South African biochar currently comes from.
TURNING WASTE INTO A VALUABLE RESOURCE
Everything that biochar entails represents the fundamental shift in thinking that is required heading into an uncertain future: the notion of turning waste into a resource – something that holds value. A new mindset based on a circular economy, one where we obtain the maximum value from resources, is much needed. Biochar is a quintessential example of this new way of thinking. Biochar production makes use of what has traditionally been thought of as ‘waste’ and creates a resource that holds tremendous value; one that can significantly enhance standards of living while catering to environmental concerns. Making charcoal is one of the most ancient of the industrial arts, and generating electricity from pyrolysis is not particularly new either. Understanding that we can use the granular ‘waste’ or by-product from these processes (biochar) to enrich soils while combatting climate change, that is the new ‘discovery’. What makes biochar such an attractive development is the diversity of its potential applications, ranging from being a soil amendment to energy recovery and water purification. As the DEA report notes: “It is suggested that any project to pursue the production of biochar should be considered alongside the range of potential uses to determine where the maximum possible bene t can be achieved, rather than limiting the options to carbon sequestration and soil amendment.”
Article first appeared in Earthwork's Magazine - http://earthworksmagazine.co.za