Eine Zeile Bil­dun­ter­schrift

Back­ground

About 10 percent of EU CO2 emis­sions could be offset by more pro­duc­tive use of biomass and plant residues through pyrol­y­sis. This is the con­clu­sion of Prof. Bruno Glaser from the Uni­ver­si­ty of Halle and author of the article “Biochar use: a pro­duc­tive alter­na­tive to carbon storage”. Biochar pro­duced from pyrolyzed (car­bonised) biomass and plant residues can be used as soil improver and as a source for other carbon appli­ca­tions such as con­struc­tion or animal feed.

11 giga­tons of carbon dioxide (CO2) per year

Green­house gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are the basis of man-made air pol­lu­tion. Man’s main con­tri­bu­tion to the global green­house effect is the emis­sion of unimag­in­ably high amounts of CO2 into the atmos­phere. This cor­re­sponds to about 11 giga­tons of carbon © per year, a mind-bog­gling amount. 80% of this is caused by exhaust gases from fossil fuels (power gen­er­a­tion, trans­port and cement and steel pro­duc­tion) and about 20% is released by agri­cul­ture (defor­esta­tion, con­ver­sion of grass­land into arable land, etc.). Due to rising pop­u­la­tion growth, green­house gas emis­sions will con­tin­ue to rise. In addi­tion, the poten­tial of natural CO2 storage in the oceans, for example, is expect­ed to decrease with rising tem­per­a­tures, which con­tributes to the green­house effect. There­fore, sus­tain­able solu­tions for the removal (seques­tra­tion) of atmos­pher­ic CO2 are needed for the global envi­ron­ment. Accord­ing to Glaser, Europe could offset 10% of its annual carbon emis­sions if only part of its annual organic waste (grain residues, forest residues, garden and green waste; about 500 mega­tons) were con­vert­ed into biochar (about 140 mega­tons).

Current options for long-term carbon storage

Carbon capture and storage (seques­tra­tion) only makes sense if it removes CO2 from the atmos­phere in the long term – at least hun­dreds of years, prefer­ably sending dew. The agri­cul­tur­al tech­niques cur­rent­ly avail­able (no tillage, deser­ti­fi­ca­tion) will con­tribute little to carbon seques­tra­tion into the soil. Accord­ing to Glaser, the con­ver­sion of agri­cul­tur­al land into grass­land (grazing land) would also only aggra­vate the current problem due to the enor­mous energy loss incurred by the con­ver­sion of plants into animal feed. All pre­vi­ous options for C‑sequestration are there­fore dealt with, includ­ing:

  • Carbon Capture and Storage (CCS): Large-scale carbon seques­tra­tion at power plants and per­ma­nent storage in under­ground deposits.
  • Carbon Capture and Use (CCU): CO2 capture, in par­tic­u­lar from com­bus­tion gases, and use in other chem­i­cal process­es.
  • Sep­a­ra­tion and storage of solid carbon in (pol­lut­ed) ocean sed­i­ments
  • Use of carbon as an adsor­bent (acti­vat­ed carbon) and sub­se­quent removal of carbon in fallow land (land­fills, aban­doned mines, deserts, etc.)
  • Afforesta­tion

Eco­nom­ic benefit thanks to stable CO2-binding

Con­ven­tion­al tech­nolo­gies for climate change mit­i­ga­tion such as bio­fu­els and CCS are “closed loop”, i.e. they only bind emitted CO2. There­fore, these tech­niques cannot reduce the actual or future CO2 content of the atmos­phere. Since they are not 100 percent effi­cient, Glaser says they will further increase the atmos­pher­ic carbon dioxide content. Biochar, on the other hand, is resis­tant to bio­chem­i­cal degra­da­tion thanks to its mol­e­c­u­lar sta­bil­i­ty. Cap­tur­ing CO2 in a stable and solid form such as biochar and using it to improve ecosys­tem ser­vices or in build­ing mate­ri­als can active­ly reduce atmos­pher­ic CO2 con­cen­tra­tions while gen­er­at­ing eco­nom­ic added value. This added value results from the pos­si­bil­i­ty of carbon-neg­a­tive food pro­duc­tion (more carbon is bound than released), greater plant pro­duc­tiv­i­ty, savings in the pur­chase of mineral fer­til­iz­ers, an increase in cor­po­rate brand value through demon­stra­bly sus­tain­able pro­duc­tion process­es and an income stream from the acqui­si­tion of CO2 cer­tifi­cates traded on the vol­un­tary carbon market.

Biochar as a build­ing mate­r­i­al

However, not only agri­cul­ture ben­e­fits from the added value gen­er­at­ed by biochar. Plant char­coal can also be used as a modern build­ing mate­r­i­al in other indus­tri­al areas such as in the con­struc­tion indus­try. Carbon fibres are state-of-the-art mate­ri­als with prop­er­ties such as low weight, high strength and chem­i­cal sta­bil­i­ty. Carbon com­pos­ites can replace steel and other metals, although they have dif­fer­ent prop­er­ties. Carbon fibres are already being used in tensile-resis­tant build­ing mate­ri­als to rein­force con­crete for special appli­ca­tions and active­ly protect the climate.

Orig­i­nal Article: Biochar use: a pro­duc­tive alter­na­tive to carbon storage
Author: Bruno Glaser
Pub­lished in: Climate Action Report, London, 2011–2012, p. 137–139