HOT|COOL NO.3/2021 - "Don't waste it!"

• It is by far the cheapest CCS technology • It actively integrates with and boosts local economies • It supports sustainable growth in the farming sector Biochar has multiple benefits besides carbon sequestration. It delivers long-term carbon sequestration, and biochar also improves soil and increases food production - it has been known for millennia. The relatively low temperature (600 degrees C) in the SkyClean pyrolysis process leaves the nutrients in biochar readily avail- able for absorption by new crops. It makes biochar a desira-ble soil additive. In recent years researchers have found biochar to possess a wide range of additional benefits for agriculture: • Biochar significantly improves the water retention in sandy and other types of dry soil • Conversely, biochar improves water flow in heavy clay soil, attractive in regions suffering from increased precipitation due to climate change • Remains of antibiotics, pesticides, hormone-like substances, and microplastics occur in slurry and manure and tend to be concentrated in the soil after fertilization. The pyrolysis process breaks down these residues into harmless constitu- ent molecules • Biochar reduces leaching of nitrogen. In addition to the benefits of biochar, pyrolysis will also help agriculture lower emissions from methane as the pyrolysis of manure fibers eliminates methane formation from the feedstock and in- corporates the constituent elements into the oil and gas fractions. The technology has caught the attention of the Danish au- thorities and is listed as one of the essential contributing technologies that will help Denmark reach its 2030 CO 2 emis- sion re-duction target.

Carbon-negative heat production can accelerate climate goals Keeping global warming within the 1.5 – 2 degrees C is not possible with reduced CO 2 emis-sions only. It also requires the large-scale application of technologies that can remove CO 2 from the atmosphere. The minimum amount of CO 2 that will need to be removed from the atmosphere to breach the maxi- mum allowance of atmospheric CO 2 specified by IPCC will be ten gigatons per year from 2055 onwards. Few CCS technologies on the horizon promise to be able to deliver at such a scale. Biochar production, however, promises to be one of the few pathways towards large-scale sustaina- ble sequestration of CO 2 at low cost since almost any type of biological residue can serve as feedstock for pyrolysis processes like the one SkyClean uses. Experts from the Technical University of Denmark and Aarhus University have estimated that Danish agriculture can reduce greenhouse gas emissions by 50 % using the SkyClean tech- nology. It is not too much of a stretch to see the existing synergy between DH and biofuel expand to include biochar-based heat production. Fun fact: to remove ten gigatons of CO 2 from the atmosphere annually, 200,000 SkyClean plants with 20 MW capacity could do the job. Special layout section, focusing on biochar Biochar is posed to enter the big league of large-scale CCS technologies Stiesdal’s SkyClean technology joins the growing number of efforts to elevate biochar from a soil-improving by-product of pyrolyzed feedstock to a center-stage role among CCS tech- nol-ogies. Biochar is a stable material that does not decompose for hundreds of years. The biochar pellet output from the SkyClean process is easily handled and spread on farmland with existing farm tools and machinery. It will integrate with farming at any stage of technological development. Among the wide variety of current and proposed carbon capture and storage (CCS) technologies, biochar production from sustainable biomass has several advantages:

For further information please contact: Jesper Ahrenfeldt,

A 20MWSkyClean plant processes 5 tons of biomass per hour and can supply 4 MWof heat output to the district heating systemwhile the rest of the energy in biomass ends up in the biochar and bio-oil.

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