Carbo Culture ($28 million to turn biomass to biochar for CO2 removal while producing clean energy)

Carbo Culture, a Finnish climate tech company founded in 2018, has developed a carbon removal technology known as Carbolysis™, which uses a pyrolysis reactor operating at high temperature and pressure to convert biomass waste into stable biochar, thereby locking carbon safely away for centuries. Additionally, the process produces syngas that can be used to generate clean electricity. Carbo Culture believes that its technology is the most efficient method for converting biomass into biochar. Carbo Culture's mission is to remove one billion tons of carbon dioxide from the atmosphere.

(This article contains 4 diagrams and 1936 words.)

Challenges: carbon emissions and BiCRS

Carbon emissions

Since the early 1900s, carbon dioxide (CO₂) levels in the atmosphere have increased by 50% due to human activities. When fossil fuels (such as coal, oil, and natural gas) are burned for energy production, transportation, and industrial processes, CO₂ is released into the atmosphere. This excess CO₂ acts as a greenhouse gas, trapping heat and causing the air and ocean temperatures to rise. CO₂ emissions play a crucial role in driving climate change.

This warming effect has caused the global average temperature to rise by about 1.1 ºC since the pre-industrial period. This has led to rising in the frequency and intensity of extreme weather events, melting of polar ice caps and glaciers and rising sea levels, shifts in species ranges and increased risk of species extinction, agriculture and food security,  and ocean acidification.

To mitigate these impacts, the Paris Agreement aims to limit global warming to well below 2 ºC above pre-industrial levels. The Intergovernmental Panel on Climate Change (IPCC) estimates that a “carbon budget” of about 500 GtCO₂, which corresponds to about ten years at current emission rates, provides a 66% chance of limiting global warming to 1.5 ºC.

Biomass Carbon Removal and Storage (BiCRS)

Biomass Carbon Removal and Storage (BiCRS) is different from Direct Air Capture (DAC) technology in that it lets plants do the hard work of scrubbing CO₂ out of the atmosphere through photosynthesis. It turns biomass into biochar or CO₂ that can be sequestered permanently, thereby removing CO₂ from the air.

One example of BiCRS technology is Bioenergy with Carbon Capture and Storage (BECCS). During BECCS, biomass is converted into bioenergy while carbon is captured and stored. The carbon in the biomass comes from CO₂ taken from the air during photosynthesis. Biomass is processed via combustion, pyrolysis, or other conversion methods. During the process, energy is extracted in useful forms of electricity, heat, etc., and  CO₂ or biochar produced can be sequestered geologically or disposed of in landfills, respectively.

Carbo Culture Technology

Carbo Culture (Carbo) has developed a biomass pyrolysis technology based on Professor Michael J. Antal’s research. Carbo has developed a pyrolysis reactor that operates at a high temperature (750 ºC) and pressure (up to 400 psig) to efficiently convert biomass into stable biochar and sequester carbon permanently. Three tons of CO₂ are removed for each ton of biochar produced. The biochar can be used in agriculture, construction, and urban landscaping applications. The produced syngas can be used to generate electricity.

Carbo’s pyrolysis system is very efficient for biochar production. When the pyrolysis process of a batch of biomass contained in a canister within the reactor is complete, the canister is removed from the reactor without substantial cooling. The following canister filled with biomass waste is loaded into the reactor for the subsequent pyrolysis cycle.

Carbo Culture reactor

The diagram below depicts the pyrolysis reactor system of Carbo for converting biomass to biochar.