Why is bioenergy essential for a sustainable energy system?

The Joint Research Center (JRC) of the European Commission has recently published a report on the use of forest biomass for energy production in the European Union (EU) . According to this report, it is essential to engage in an honest discussion to “clarify the debate around the sustainability of wood-based bioenergy”.

This call comes at just the right time. Opinions are divided on the climate neutrality of biomass as an energy source, and many are those who allow themselves to be influenced by subjective interpretations or by their personal interests. Thus, when scientific articles are cited, the facts are often presented out of context.

In order to consider climate-friendly options for our future energy system, we must be much more nuanced and avoid falling into a Manichean vision.

Biomass and bioenergy: what are we talking about?

To put it simply, the combustion of biomass (plant matter) produces heat that can be used to create energy or biofuels. More commonly known as bioenergy, this type of energy can be created from different organic materials such as agricultural waste (for example sugar cane bagasse or corn cobs), wood chips and aggregates from cuttings. thinning and residues from the timber industry, or even dried animal excrement. All of these organic materials contain solar energy that they have stored and absorbed.

Bioenergy is often described as a practical solution to meet the energy needs of populations. However, this practice is older than all other derived energy sources. Indeed, already at the time of the cavemen, the combustion of wood was used to warm up.

Biomass: sustainable energy?

The European Academies Science Advisory Council (EASAC) is one of the strongest opponents of bioenergy because it would be harmful to the climate. However, this vision is too reductive. If we consider the carbon footprint as a whole, the analysis is different.

One of the main criticisms against biomass combustion concerns CO₂ emissions. The latter would have the same effect on global warming as the CO₂ emissions generated by the combustion of fossil fuels.

The IEA Bioenergy organization explains why this comparison is inaccurate: “The combustion of biomass for energy purposes does produce carbon emissions, but these emissions are an integral part of the continuous exchange of carbon between the biosphere and the environment. 'atmosphere. Therefore, the shift from fossil fuels to bioenergy and the effect of such a shift on atmospheric greenhouse gas (GHG) concentrations cannot be studied by comparing CO₂ emissions. at the point of combustion.

According to Øyvind Skreiberg, scientific director at SINTEF Energy Research, there is a fixed stock of carbon on Earth and in the atmosphere: “Global warming is the result of an increase in carbon in the atmosphere, in particular CO ₂. If biomass burning does not affect the fixed carbon stock, then there is no global warming caused by biomass burning, because there is no net addition of CO₂ in the atmosphere”.

In Directive (EU) 2018/2001 of the European Parliament and of the Council of 11 December 2018 on the promotion of the use of energy produced from renewable sources, CO_{2< /sub> resulting from the combustion of biomass are considered climate neutral in the energy field. In other words, "this means that only a net increase in the use of biomass can lead to an increase in CO2 emissions, and thus contribute to global warming", explains Øyvind Skreiberg .}

What about forest conservation?

One of the main arguments put forward by EASAC and the JRC concerns the preservation of forests. Currently, the protection of tropical rainforests is a global issue. However, the idea that deforestation is happening all over the world is inaccurate. In Norway and many parts of Europe, the stock of forest biomass is increasing.

A 2017 article, published in the journal Biofuels, Bioproducts and Biorefining, challenged the idea that greater use of biomass for energy purposes would have negative impacts on deforestation: “Projections show that in l Absent additional demand for wood pellets, the area of ​​natural forests is expected to decline by 2030 (a loss of area in the range of 450 to 15,000 km²). In case of high demand for wood pellets, a larger area of ​​natural forests would be preserved (between 2000 and 7500 km²) and between 8000 and 20,000 km²of pine plantations would be created”.

Professor Francesco Cherubini, director of the Industrial Ecology program at the Norwegian University of Science and Technology (NTNU), explains that active forest management preserves forests as carbon sinks and not as sources of carbon: "Good management of woods and forests contributes to increasing the stock of forest carbon while providing biomass for multiple purposes, including energy".

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What decisions in terms of land use planning?

Of course, the availability of land and its use for beneficial purposes are important considerations when weighing the pros and cons of using biomass. However, it is not just about analyzing the amount of land available. Again, it is difficult to talk about stock biomass in isolation. This thinking needs to be done with the help of other factors such as climate, impacts of biomass diversity and the opportunity cost of land use.

Such a debate also raises many questions about the current food system. “Nearly half of the land on the planet is used to feed animals, not humans. For example, soybean cultivation is the main cause of deforestation in the Amazon, but more than 75% of the crops are used to feed animals,” explains Francesco Cherubini.

The NTNU professor adds that “bioenergy must be combined with other options to reduce the impact on climate change and achieve the goals of the Paris Agreement. We should not see this as a competition between on the one hand the use of available land to expand the area of ​​forests, and on the other hand cultivation for energy purposes. We need both. »

How to maintain the carbon footprint?

Apart from the direct reduction of CO₂ emissions, if the carbon balance is to be maintained, CO₂ emissions from fossil fuels must be offset by increasing the Earth's non-fossil carbon stock or other means of removing CO₂ from the biosphere. However, there is a limit to the amount of carbon that can be naturally absorbed by the oceans and terrestrial biosphere. Currently, emission levels are far beyond the Earth's natural capacity.

Today, this balance is not maintained, to the point that the stock of carbon in the atmosphere exceeds critical thresholds and influences the average increase in global temperature.

Thus, labeling bioenergy as “bad” is a mistake. Limiting the repercussions of climate change requires making considerable efforts, in particular to drastically reduce emissions of fossil origin. Bioenergy alone will not solve the climate crisis, but it will play a crucial role as part of broader change. For Francesco Cherubini, “we need combined and multiple solutions, which combine the management of forests, their expansion and conservation, with improvements in the agri-food sector. »

Given the need to reduce emissions of fossil origin, CO₂ capture and storage (CCS) technologies can be used in conjunction with bioenergy. According to the Intergovernmental Panel on Climate Change (IPCC), this process alone would permanently store huge amounts of CO₂ each year, although it all depends on the long-term availability of biomass and large-scale implementation of CCS.

There are many other biomass-based climate-positive solutions beyond simple combustion that can contribute to the energy transition. For example, storing charcoal in the ground improves soil quality while creating a carbon sink, an option for both cities and rural areas. Increased use of wood as a construction material will also store carbon in the long term.

Biomass and bioenergy: what plan for the future?

The planet currently needs a wide choice of sustainable options that take into account the sometimes complex local contexts and the increased needs of society in terms of materials and energy.

As the International Energy Agency (IEA) recently pointed out, forest biomass should not be overlooked. Instead, research should focus on establishing better management and regulatory practices to enable sustainable production.

Article translated from Forbes US – Author: Nils Rokke

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