The government places great reliance on technological solutions in its climate policy, even if the effect is not always good enough. It is important that the upcoming action plan for brown biorefining looks at how much biochar and pyrolysis can actually contribute to the green transition in 2030, and does not end up being another romance with technological solutions.

In 2021, a broad gathering of the parliamentary parties entered into an "Agreement on the green transformation of Danish agriculture". The agreement must ensure that agriculture can meet the climate objectives. In the agreement, a number of development initiatives are being worked on to ensure technical reduction potentials for DKK 5 million. tonnes of CO2e out of the 8 million tonnes of CO2e to be reduced in the entire forestry and agricultural sector in 20301. One of these development initiatives is support for brown biorefining, which the parties to the agreement have assessed can contribute to storing 2 million tonnes of CO2e in agricultural land in 2030.
Brown biorefining mainly consists of the pyrolysis technology. During pyrolysis, a biomass, for example straw or sewage sludge, is heated under oxygen-free conditions, with which an energy-containing gas or oil is produced, and a part of the biomass, called biochar, is charred. Biochar can be spread on fields, where it forms a relatively stable CO2 store. In this way, biochar can help to ensure that agriculture can live up to its climate obligations.

It sounds very good, but realistically it will be very difficult to make it a reality before 2030. In Denmark, we only have one full-scale pyrolysis plant, which is being established, while the Danish Energy Agency has estimated that it must be built and commissioned between 80 and 370 pyrolysis plants by 2030 to reach the target2. There is therefore a long way to go before the technology can contribute 2 million. tonnes of CO2e. The Climate Council has previously assessed that there is a high risk associated with pyrolysis as a climate change agent3. The long-term effect of biochar on soil, drinking water and food production in the fields has not yet been investigated either.

In addition, one of the major problems with pyrolysis is that we have a limited amount of biomass that can be put into the pyrolysis plants with climatic advantages. According to the Energy Agency, the Danish biomass base consists of, among other things, of straw, animal manure, fiber residues from biogas plants, sewage sludge and wood from Danish forests and wood waste4. It is important that residual products are used that have a short rotting time, as e.g. wood and wood waste, which has a long rotting time, will have a worse climate effect when it is pyrolysed.

We must use biomass for many different functions when we move away from using fossil oil for our products. Straw is, for example, in demand for feed, biogas and other energy, it can be used as a building material, but also has a soil-improving and CO2-storing effect if it is allowed to remain on the field. Wood is in demand for, among other things, construction, packaging, the clothing industry and the energy sector, but neither straw nor wood are unlimited resources. It is therefore important that we use biomass where it provides the greatest benefit - and not blindly pour it into pyrolysis plants.

Denmark's consumption of wood for energy is already three times higher than what the UN climate panel considers to be sustainable and two-thirds of the wood is imported5. For this reason alone, it is important to avoid further imports of biomass from abroad – including especially wood. In addition, increased imports of biomass effectively pass the climate bill onto the exporting countries. If wood is cut in other countries and exported to Denmark, it will count negatively in the exporting country's climate statement. It cannot be a sustainable solution to achieve Denmark's climate goals.

Pyrolysis is not in itself an unwise technology, but it is important that we do not hinge our climate action on a technology that may not be able to deliver the necessary CO2 reductions in time. But what should we do instead?

If a tax is placed on wood energy that corresponds to the climate impact, we will quickly achieve a significant climate effect. The current tax exemption distorts the market, and makes burning wood more attractive than other, less climate-damaging forms of energy.

Another solution worth focusing on is afforestation. The government's foundation states a goal to establish 250.000 ha of forest in Denmark. Forests can function as a natural CO2 storage, which can simultaneously increase biodiversity and function as a nitrogen input. In addition, a quick announcement about and implementation of the announced climate tax on agriculture could contribute to faster restructuring of the sector.

In other words, the government and our politicians have to be realistic with the means of action that are invested in, so that we are sure of being able to reach the climate goals for 2030, and so that we use our biomass where it makes the most sense.

The debate article was published in Klimamonitor on 26 January 2024.