China Biochar Could Scale Carbon Removal on Abandoned Cropland

Biochar has long been regarded as a promising climate solution, yet one that has been hard to scale. The principle is straightforward: plant matter is transformed into a stable, carbon-rich material and placed in soil, where its carbon may stay stored for decades or even centuries.

The challenge has been securing sufficient supply. In many areas, there is not enough suitable residual biomass to support biochar at a large scale.

However, new research indicates that China may be able to address this constraint by cultivating bioenergy crops on abandoned cropland and turning them into biochar. If it works, this model could allow biochar to scale while making it considerably cheaper than many rival carbon-removal methods.

“Our work shows that integrating bioenergy crops into the system can significantly expand its potential while keeping costs low,” said corresponding author Wei Li of Tsinghua University.

Biochar’s key carbon advantages

Many carbon-removal approaches are costly, complex, or both. They may depend on major industrial facilities, substantial electricity use, permanent underground storage, or monitoring arrangements that are challenging to expand rapidly.

Biochar works differently. As plants grow, they take CO2 from the atmosphere. Pyrolysis then changes some of the carbon in that plant material into a more durable and stable substance. Instead of being released back into the air, that carbon is stored in soils.

It can also provide benefits beyond climate objectives, making the case for its use easier. Biochar may increase soil organic carbon, improve soils’ ability to hold nutrients and, in certain cases, lower emissions of greenhouse gases such as nitrous oxide.

In other words, investment is not limited to carbon removal: it may improve agricultural productivity as well as reduce farming-related pollution.

Biochar’s big supply problem

Most current biochar production uses residues from agriculture and forestry. Although this is convenient because the biomass is already available, it restricts the scale that biochar can achieve.

Such residues are dispersed across wide areas, while moving bulky plant material over long distances soon becomes costly.

The new study considers an important alternative: rather than restricting biochar to leftovers, could a dependable biomass source be developed by growing dedicated energy crops without competing with food production? Abandoned cropland is central to that proposition.

Testing biochar at scale

The researchers assessed this combined crop-and-biochar model against real-world constraints, including the distribution of China’s biomass power plants, transport networks and practical supply-chain conditions.

Their calculations suggest that bioenergy crops cultivated on abandoned cropland could enable around 25.8 million tonnes of CO2 removal annually through biochar.

This is far from insignificant. It is also broadly similar to the amount of carbon removal that biochar could provide from agricultural and forestry residues, which have traditionally been its principal feedstock.

The proposal is not to displace residues, but to establish a second source of supply so that feedstock availability no longer constrains biochar.

Breaking down the costs

One estimate is particularly notable. According to the study, biochar made through this integrated model would cost roughly $9.6 per tonne of CO2 removed.

The researchers contrast this figure with BECCS (bioenergy with carbon capture and storage), a carbon-removal route requiring more extensive infrastructure.

Their analysis puts BECCS at approximately $90.9 per tonne. While it can remove marginally more carbon in some configurations, it needs costly capture technology, transport and storage infrastructure. Both the expense and the complexity can obstruct rapid scaling.

“Cost is a critical factor for large-scale deployment,” the authors wrote.

“Biochar stands out because it delivers meaningful carbon removal at a fraction of the cost of alternative technologies.”

At the scale of national carbon-removal strategies, this difference in cost is important. It separates a pilot scheme from a solution that could be deployed widely.”

How big biochar could get

The study also considers the outcome if the system were expanded and optimised. This would involve growing more energy crops, raising biomass supply and constructing additional pyrolysis facilities in appropriate locations.

Under this upper-bound scenario, the researchers calculate that biochar in China might reach as much as 1.88 billion tonnes of CO2 removal each year.

This is plainly not an immediate prospect, as it relies on land being available, infrastructure being built and policy support being maintained. Still, it demonstrates that biochar need not remain small in scale.

If investment and supply chains align, it could become a significant tool rather than a specialist addition.

The role of abandoned cropland

Eastern and north-eastern China are identified by the study as areas with particularly strong potential, mainly because they combine biomass resources with established infrastructure. This is important, since transport costs can quietly determine whether biochar is economically viable.

Selecting abandoned cropland is also intentional. Bioenergy schemes can prove controversial when they compete with food production.

Using underused land for energy crops is intended to lessen this tension and make expansion more politically achievable.

It is not an ideal answer: “abandoned” land may still hold ecological importance or serve local purposes. Nevertheless, it is a more realistic starting point than converting productive farmland.

Barriers to scaling biochar

Although the researchers are positive, they acknowledge that the approach is not plug-and-play. Expanding biochar would demand investment in pyrolysis infrastructure, closer links with existing agricultural and energy systems, and dependable biomass supply chains.

Policy measures and carbon-market incentives would be equally significant, giving farmers and businesses reasons to adopt the practice and continue it over time.

“Our findings suggest that biochar, especially when paired with bioenergy crops, could become a cornerstone of climate mitigation strategies,” the researchers said.

“With the right policies and investments, it has the potential to deliver both environmental and economic benefits.”

Outlook for biochar

The research recasts biochar from a worthwhile concept that has been difficult to scale into one that could grow substantially if biomass supply is treated as the main issue.

Cultivating bioenergy crops on abandoned cropland could greatly increase the scale of biochar while keeping costs relatively low, at least in principle.

Since biochar can also enhance soil health, it is not solely a climate tool. Rather, it provides a carbon-removal strategy that can sit alongside agricultural gains.

If China is committed to carbon neutrality and needs options that are practical, affordable and scalable, this research presents a compelling argument for giving biochar greater attention.