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We at Change Inc. often receive critical questions about biomass energy generation. For example, in response to articles on renewable energy generation figures, which typically include biomass. 'Why does burning wood count as green energy? It's not sustainable at all, is it?' The social debate about biomass has raged on for years. How does Dutch science view this controversial energy source?

The Netherlands has more than 200 biomass power plants where both European and international logging wood is burned and converted into energy | Credit: Getty Images

Biomass is an umbrella term for all renewable matter of plant or animal origin. Think wood, manure, oils or food scraps. You can do various things with it, such as process it into new food, upgrade it into a building material or use it as a raw material in clothing. You can also gain energy from biomass. This is done through fermentation, gasification or combustion of the material. Because you can theoretically grow biomass endlessly, bioenergy can be called renewable energy.

200 power plants

At the moment, wood is the most popular bio-resource to extract energy from. No specific percentage can be attached to it, but it is by far the largest share in the bio-energy mix. This is also true for the Netherlands. Our country has over two hundred biomass plants where both European and international logging wood is burned and converted into energy. In 2023, 7.3 percent of our electricity came from biomass. The share in the renewable energy mix - which includes heat - is higher; in 2022 about 40 percent.

Difficult judgment

The energy source may be renewable, but is it also sustainable? That question has been the subject of vigorous public debate for some time. The result is a jumble of information; for every argument in defense of bioenergy, one can find an objection, and vice versa. This makes it difficult for the average person to form an opinion. How do Dutch researchers view this complicated debate?

Majority of scientists

"Using biomass as an energy source once started as a green dream," explains ecology professor Louise Vet. "That arose from the beautiful idea that you could plant trees to offset biomass emissions. Then you would be in some kind of equilibrium. It endeared people, but it's not reality."

Vet says on the phone that she has had her fill of the biomass debate and prefers not to spend another second on it. Indeed, she compares the discussion to the overall climate discourse, which not long ago was disproportionately tainted by voices claiming that global warming is not all that bad.

"Those few climate deniers made it seem in the media that the discussion was one against one. This made it completely unclear to the reader that in reality, there are lopsided relations. The same is true of the biomass debate. The majority of scientists say it is not a good idea to burn wood for energy."

Growing doubts

The green dream of which Vet speaks was initially propagated by the Intergovernmental Panel on Climate Change (IPCC). Moreover, biomass burning took off when the European Union labeled it CO2 neutral. Meanwhile, the IPCC is more cautious in its wording. Energy from biomass is now "not automatically seen as carbon neutral, even in cases where biomass is deemed to be sustainably produced. In the Netherlands, the Social and Economic Council (SER) recommended in 2020 that subsidies for biomass as an energy source be stopped. Indeed, the organization emphasized that as a society we will increasingly need biomass for other applications. Moreover, the SER felt that the concept of biomass in the Netherlands had become too one-sided, as the emphasis has shifted to burning wood pellets (compressed pieces of wood).

Fire Letters

And indeed, academia is also beginning to increasingly oppose the burning of trees for our energy supply. In 2018, some 800 scientists sent an open letter to the European Parliament protesting biomass as an energy source. In 2021, another 500 scientists sent a similar cry from the heart.

Contrast theory and practice

What are these concerns based on? Mainly on the difference between the theory and practice of woody bioenergy. At the theoretical level, there is little to worry about. One takes a tree, cuts it down and burns it, releasing the CO2 the tree has stored into the atmosphere. To compensate, the same kind of tree is planted again and the CO2 is sucked back out of the atmosphere over the course of decades. On paper: zero net emissions, a source of energy that is renewable, and - paired with the right policies - a system that does not harm biodiversity.

But the practice is different. Indeed, the replanting of trees after felling appears to be limited, even though it is essential for the carbon neutrality of the energy source. "Bioenergy has become a huge industrial process, making a huge amount of money from the companies involved," Vet says. "It is a global stream that has led to large-scale forest destruction in Eastern Europe and North America. Millions of tons of wood pellets are being imported. And in America, for example, there is no replanting obligation at all."

Logging of old-growth forests

There have been many reports in recent years about foreign old-growth forests disappearing for firewood extraction. In 2021, for example, it was revealed that Dutch biomass is leading to a clearing of forests in Estonia. And also in Eastern European countries, including Romania, European demand for woody biomass is leading to the mass destruction of protected forests. Where such forests were first seen as 'carbon sinks' - into which CO2 from the air disappeared - thanks to large-scale felling, they are now seen precisely as polluters.

The Dutch government says it only imports trees from areas where it can monitor sustainability criteria. But according to Vet, this is a wash. "The Netherlands is not very good at enforcement. Moreover, this is not enforceable at all. In fact, the criteria are tampered with considerably in those countries."

Paying off debt

Another problematic issue with bioenergy is the so-called carbon debt. Burning wood emits a lot of CO2, per unit even more than fossil fuels. That "debt" is only paid off over decades, when the same tree is fully grown and the CO2 has been reabsorbed from the air. But the next ten years in particular are crucial for achieving the Paris climate agreement, and for preventing irreversible climate damage. There are certain limits, called tipping points, which we must avoid at all costs. Urgenda gives as an example the melting of permafrost, which also releases a lot of greenhouse gases into the atmosphere. Tipping points cannot be reversed, and for that reason it is important to emit as little CO2 as possible in the next ten years. Energy sources with a high carbon debt are therefore, for that reason, a less good option than, say, solar panels or wind turbines.

Quitting the cap

The gap between theory and practice also endorses Edwin Hamoen, biorefinery program manager (Wageningen University & Research). "Biomass as an energy source is not necessarily bad. In the future, we will increasingly use biomass for high-value applications, but in many cases that is not possible at the moment. This is because we are still in a transition. So during that transition, using bio-waste as an energy source is not a bad thing. But cutting down trees that should not have been cut down, we have to stop that as soon as possible. That's really not a good development. Everyone understands that clear-cutting Canadian forests is a very bad idea."

Good for transition

Although Hamoen is convinced that burning logging wood should stop, in retrospect he does not think it is wrong that the extraction of energy from woody biomass has taken place. "After all, it has taught us a lot about the use of biomass. But it is something we should only do during the transition to higher-value use. In the future, we should only get energy from biomass at the moment when we can't do anything else with it. And whether that will be via gasification, gasification or combustion, that remains to be seen. Although I don't think there will be much room left for combustion."

Meanwhile, the government no longer issues subsidies for burning biomass. But the source is still placed in the same list as other renewable sources, and is invariably included in reports of renewable energy generation. This gives the impression that it is a renewable energy source. According to Hamoen, this simply has to do with the fact that it was once given that sticker, which was then never removed. "The Dutch government says it needs biomass to meet the climate goals, and so it is all about making sure it keeps that label. So it has more to do with policy than anything else."

Other biomass

Getting energy from felled trees may not be the right solution direction, but do other forms of bio-waste have potential as a suitable and sustainable source of energy in the future? According to Vet, it is unrealistic to think you can replace the current supply with it. "You're talking about millions of tons. If you wanted to extract energy from rapeseed oil, for example, you'd have to fill more or less the whole of the Netherlands with it. So I think other forms are very difficult. You can do small things, though, like fermenting waste or brown water. And digestion is better than incineration, because then you're left with a product that you can give back to the soil. Burning is really a very low-grade application of biomass, really the very last thing you should do with it. After all, you can get so many good substances out of it."

Hamoen feels the same way. "It's often about the magic year 2050. I think very little biomass will be burned by then. We should be to the point by then where we can use biomass in other products." Moreover, he thinks the current share of biomass in the energy mix will be filled in by other, more sustainable sources of energy in the future. "Biomass combustion could well make a small-scale contribution to our energy supply in the future. But you have to look from what is available then, not from what is needed."

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