Hydrochar in agriculture
We offer 5 steps how agriculture should shift its CO2 reduction activities towards solid carbon upcycling: hydrochar, pyrolysis, torrefaction, and more.
There is no way around it: agriculture is a major contributor to CO2 emissions, and with the global population expected to increase in the foreseeable future, we face the dilemma of having to feed more mouths, which, if we continue to employ the same technologies and processes as today, will inevitably increase the CO2 footprint of the industry.
This is especially true for animal-based agriculture, which will inevitably be a part of food production as long as barely arable lands can be used for ranching but not for plant-based farming.
Case in point is Brazilian meatpacking conglomerate JBS, whose dilemma has recently made the news. According to a new study, the carbon footprint has increased by 50% over the last five years, and now exceeds that of Italy. This contrasts with the company’s goal to become carbon neutral by 2040.
JBS disputes the numbers, but this newsletter is not about this inevitably politicized discussion, but about the obvious solution for agricultural carbon ecosystem.
We can offer five steps how agriculture can adopt solid carbon upcycling and sequestration technologies — hydrochar and pyrolysis foremost among them — to reduce their CO2 footprint and improve their operations at the same time.
1. Agriculture is a major producer of CO2
The simple reality is that agriculture is in the business of transforming carbon, with the aid of other nutrients. One step of the transformation cycle is when the biomass agriculture produces, be it animals or plants, is left to decompose. This is the key step that makes agricultural production a major contributor to CO2 production. And this is the step where solid carbon technologies tackle, by stabilizing, upcycling, and reusing biomass, before it can decompose.
2. Agriculture is a major producer of carbon-rich biomass
Agriculture produces massive amounts of biomass: wet or dry, plant-based or animal-based. Most of it is carbon and nutrient rich.
Biomass comes from many sources:
Wood and forestry residues: forest residues, bark, sawmill by-products, industrial residues, waste wood
Agricultural by-products: intercrops, vegetable cultivation residues, beet leaves, straw from cereals, rapeseed, maize, sunflowers, animal excrements
Municipal waste: biowaste, green waste, paper and cardboard residues, kitchen and canteen waste, market waste, commercial food waste, municipal and industrial sewage sludge
Residues from industrial production of food: animal feed, chemicals, pharmaceuticals, yeast, bioethanol, slaughterhouse, fish processing, fruit and vegetable processing, production of vegetable & animal oils and fats, milk processing, production of starch and starch products, production of bakery and pasta products, beverage production, sugar production, production of confectionery, production of finished products, coffee production, nut shell processing, tobacco processing, ethanol production
Other residues: stalk and woody biomass from landscape conservation and communal green spaces, cemetery areas, heath areas, orchards, vineyards, bog areas, roadsides, railway lines, waterways, alluvial wood, aquatic plants.
Taking Germany as an example, this currently amounts to a biomass residue potential of some 150 million metric tons (dry matter). Wood and forestry residues account for 43%, agricultural by-products for 30%, municipal waste for 12%, industrial residues for 9% and other residues for 6%.
But not all of this biomass potential can be used due to technological, economic, or regulatory limitations. Our goal is to make this currently unusable biomass available for upcycling, reuse, and sequestration.
In Germany, 35% of all theoretically usable biomass has not been used so far due to various restrictions, some 53 million metric tons per year. Of the remaining 100 million tons, 67 million tons are already used today, leaving 20% or 31 million tons unused each year — often because these materials cannot be directly used for combustion or recycling. For these materials, upgrading through hydrothermal carbonization or pyrolysis can make utilization possible after all.
In particular wet biomass has very little economic value, as evidenced by the fact that agricultural operations often have to pay to discard it as organic waste. This is both ecologically damaging and money left in the field.
3. Biochars can be used as soil ameliorants
Biochars — hydrochar and pyrochar — can positively influence soil functions. Principally, this is caused by an increase in the water storage capacity and an improvement in the adsorption capacity for nutrients and humic substances.
In agriculture on sandy sites, hydrochar and pyrochar can ensure that plants can survive dry periods with less water stress (such as in temporary dry regions) and they can contribute significantly to the storage of cationic nutrients (ammonium, potassium, magnesium and calcium ions) in the soil. Potential pollutants, especially organic pollutants, can also be bound and inactivated.
The more porous hydrochar and pyrochar are (micropores, reactive surface) and the lower the existing water storage and sorption capacity of the respective soil, the greater the positive effects can be. Particularly impoverished, sandy soils benefit here and can then be better used for agriculture and thus help to bind further CO2 from the atmosphere.
4. Carbon removal certificates offer a new income stream
The carbon produced from the residues opens up the possibility for the owners of the raw materials (farmers, municipalities, industry and consumers) to use the carbon produced either in agriculture to improve the soil, as a CO2-neutral fuel or, in the case of long-term storage, to generate negative CO2 emissions.
The latter requires a functioning system of monitoring and accounting (a project at act4carbon) in order to enable traceable CO2 compensation with these certificates.
In parallel, nutrients such as nitrate, phosphate and others become available and recordable during the production of hydrochar. These nutrients become available in a relatively energy-neutral way and without further damage to nature (during production or extraction).
This opens up a wide path for earnings. In the future, care will have to be taken to ensure that these nutrients are available without consuming large amounts of resources. Appropriate certificates (e.g. “nutrients from residues”) could also be used to secure and trade them.
5. Improved soil enables the shift toward sustainable plant-based agriculture
Large parts of agricultural lands are barely or only temporarily arable. Often these barely arable lands are in regions that are already economically deprived, so expensive soil ameliorants are not available. The current practice is to use these lands for ruminants, grazing animals like cattle that can digest the hardscrabble plants.
But as mentioned above, cattle are major producers of greenhouse gases such as methane. So if we are interested in shifting food consumption — and agricultural productions — away from animal-based to plant-based, we have to come up with solutions not only to improve but also to stabilize soil quality using stable carbon (terra preta being a well-known example).
This is a key reason why we focus on solid carbon upcycling technologies such as hydrothermal carbonization and pyrolysis. They are well-established technologically, easier to implement in hard-to-access areas, don’t require long transportation routes or pipeline construction, and immediately make use of the biomass that is created within agriculture.