Biochar has quietly become one of the most promising climate tools we have. It locks carbon away for centuries, improves soils, reduces fertiliser use, treats contaminated land, generates renewable heat, and can even be used in construction materials. But one question matters more than any other: what is the best way to produce it?
A new study from Chalmers University in Sweden [7.7°N, 12.0°E] compares the three major thermochemical technologies — pyrolysis, gasification and hydrothermal carbonization (HTC) — and shows how each performs in terms of carbon retention, energy production and environmental impact.
The message is clear: the right technology choices could unlock large-scale climate benefits, especially in the cooler North.
1. Pyrolysis: the carbon-locking champion
Across the studies analysed, slow pyrolysis consistently produced biochar with the highest and most stable carbon content, making it the top choice for long-term carbon sequestration.
- Typical carbon concentrations reached ~65% (e.g. 65.6% at 650°C)
- Yields were solid and predictable across many feedstocks (wood, crop residues, organic waste).
- Operating temperatures preserve a large fraction of biomass carbon.
For countries like Canada, Sweden, Finland and Scotland, where forestry residues are abundant, this is a powerful insight. Pyrolysis plants located near sawmills, paper mills or logging operations could sequester huge carbon volumes while supplying renewable heat to communities.
It also strengthens the case for biochar integration into carbon markets, because pyrolysis offers the most reliable carbon permanence.
2. Gasification: lower char yield, higher energy efficiency
Gasification runs at higher temperatures, meaning less char is produced, but more energy is recovered as syngas, a clean combustible gas.
One study summarised in the paper showed that while pyrolysis produced biochar with ~65% carbon, gasification of similar feedstocks yielded much smaller char fractions, with more carbon converted into gas and heat.
This makes gasification strategically valuable when:
- energy security is a priority,
- district heating systems need reliable low-carbon heat,
- remote communities need clean, local fuel.
Northern Europe already excels at district heating. Gasification-derived syngas could be an important complement to wind and hydropower, providing dispatchable renewable heat—especially during long dark winters.
Canada’s northern and remote communities, many of which rely on imported diesel, could gain energy independence by gasifying local forestry or agricultural residues.
3. Hydrothermal carbonisation (HTC): a winner for wet feedstocks
HTC shines where pyrolysis and gasification struggle—wet biomass, such as food waste, sewage sludge, or agricultural residues with high moisture.
The review highlights that HTC:
- avoids the energy cost of drying
- produces a coal-like “hydrochar”
- works at moderate temperatures (180–250°C)
- can be integrated with wastewater treatment plants.
For cold-climate countries with extensive municipal and agricultural systems, HTC offers a circular solution: convert unavoidable wet wastes into a useful soil amendment or carbon-sequestration material, without burning energy on drying.
Hydrochar is not as stable as pyrolysis biochar, but when applied to soils or blended into growing media, it still contributes to carbon storage and nutrient recycling.
4. Why these findings matter for Canada and Northern Europe
These regions stand to benefit more than almost anywhere else from smarter biochar production:
Huge feedstock potential
Forestry by-products (bark, sawdust, slash), manure, crop residues, municipal wastes and storm-damaged timber provide steady biomass streams.
Cold-climate energy needs
Renewable heat is crucial.
Gasification and pyrolysis can both produce heat alongside biochar—strengthening winter energy security.
Soils that benefit from improvement
Many northern soils are acidic or nutrient-poor.
Biochar can improve water retention, boost yields and reduce fertiliser need.
Climate goals demanding negative emissions
Biochar is one of the few scalable negative-emissions pathways available today.
Pyrolysis-derived char is particularly valuable because of its long-term carbon stability.
Rural and Indigenous economic opportunities
Decentralised plants can create local jobs, improve waste management and support community-led energy transitions.
5. The study’s biggest takeaway: match the technology to the biomass and the need
The research makes one conclusion absolutely clear: there is no single “best” technology—only the best technology for a specific goal.
- If the goal is maximum carbon removal, choose slow pyrolysis.
- If the goal is renewable, dispatchable energy, choose gasification.
- If the goal is processing wet waste streams, choose HTC.
Canada and Northern Europe have all three needs.
The smart path forward is a portfolio of biochar technologies deployed where they fit best.
A climate opportunity waiting to be scaled
The findings show that biochar technologies are mature, flexible and capable of delivering both negative emissions and renewable energy. For countries seeking fast and practical climate solutions, that combination is rare.
Canada, Scandinavia and northern European regions are uniquely positioned to lead, thanks to biomass availability, engineering capacity and strong climate policy. With the right investment, biochar systems could become pillars of their clean-energy and carbon-removal strategies.
This is not a speculative future.
It is technology ready for deployment today.
Source
Performance analysis of sustainable technologies for biochar production: A comprehensive review, Energy Reports, 2023-03-29
Comparative assessment of biochar-producing thermochemical technologies for sustainability, Sustainable Materials and Technologies, 2025-11-07
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