Why Bioenergy Matters In Our Future Sustainable Energy System

The Joint Research Centre for the European Commission recently published a report on the use of woody biomass for EU energy production, calling for an honest discussion to “detoxify the debate surrounding the sustainability of wood-based bioenergy.” It’s a very timely discussion. There are differing opinions about the climate neutrality of biomass for energy purposes. Many of these opinions are considered to be influenced by subjective interpretations and special interests. Facts are often repeated out of context when referencing scientific papers. When considering our future energy systems, the discussion should be much more nuanced than simply considering whether something is green or not.

Biomass (plant matter) combustion creates heat and can also be utilised to generate power or biofuels. This is commonly referred to as bioenergy. Agricultural wastes such as sugarcane bagasse and corn cobs, wood chips and pellets from thinnings and wood industry residues, and even dried animal faeces all fall into this category. They all have stored energy absorbed naturally from the sun as organic stuff.

Bioenergy is frequently promoted as a trendy solution to our energy demands, yet it’s an idea that predates any other derived energy source, dating back to when our cave-dwelling predecessors kept warm by burning wood logs.

EASAC, the European Academies Science Advisory Council, is one of the most outspoken critics of biomass as a source of energy. But is it that simple? A different picture emerges when considering the entire carbon balance between the Earth and its atmosphere. Critiques argue that the CO2 emissions from biomass combustion have the same global warming effect as CO2 generated from the combustion of fossil fuels. However, the International Energy Agency (IEA) Bioenergy has highlighted why this isn’t a fair comparison: “Burning biomass for energy releases carbon into the atmosphere, which is part of the ongoing carbon cycle between the biosphere and the atmosphere. On the other hand, Fossil fuel emissions represent a linear flow of carbon from geological storage to the atmosphere. As a result, comparing CO2 emissions at the point of combustion cannot be used to estimate the effect of switching from fossil fuels to biomass on atmospheric GHG concentrations.”

According to Oyvind Skreiberg, a chief scientist at SINTEF Energy Research, there is a fixed sum of carbon stock on Earth and its atmosphere: “Global warming is a result of the movement of carbon into the atmosphere, mainly as CO2. If the fixed carbon stock embedded in biomass remains constant, there is no net global warming from biomass combustion because there is no net addition of CO2 to the atmosphere.” The EU categorised direct CO2 emissions from biomass as climate neutral in the energy sector in its amended renewable energy policy. Changes in the carbon stock embedded in biomass and reported in the land-use sector account for any non-neutrality in either direction. Skreiberg states, “This means that increasing the net use of biomass is the only way to raise direct CO2 emissions and, as a result, net global warming. If the usage of biomass stabilises at a greater level, a new equilibrium between the carbon stock in biomass on Earth and the carbon stock in the atmosphere will be reached. “

Forest preservation is one of the most important arguments made by EASAC, and the JRC is regarding the preservation of forests. While rainforest destruction is considered to be a major issue worldwide, deforestation does not occur everywhere. Forest biomass stock is actually increasing throughout Norway and large parts of Europe. A study published in the journal Biofuels, Bioproducts, and Biorefining in 2017 refuted the notion that increasing biomass use for energy would result in deforestation: “Natural timberland area is expected to shrink by 450–15,000 km2 by 2030 if there is no additional demand for wood pellets, according to projections. More natural forest (2,000–7,500 km2) is conserved in the high wood pellet demand scenario, and more pine plantation (8,000–20,000 km2) is established.”

“Well managed areas of timberland and forest contribute to the rising forest carbon store while producing biomass for numerous reasons, including energy,” says Professor Francesco Cherubini, director of the Industrial Ecology department at Norway’s NTNU university. “Active forest management secures forests as carbon sinks and not carbon sources.” The availability of land and possibilities for beneficial land-use changes are, of course, important considerations when evaluating biomass potential and climatic impact. But this is about more than the amount of available land. Once again, it is difficult to talk about the biomass stock in isolation. The climate, biomass diversity impacts and the opportunity cost of the land must also be considered.

Such discussion also raises big questions about the food systems of today. “Almost 50% of the planet’s territory is occupied by animals, not people. As an example, soybean growth is the main cause for the deforestation of the Amazon, but more than 75% of the crop is used to feed animals,” says Cherubini. “Bioenergy must be allowed alongside other climate change mitigation strategies in order to achieve the Paris climate targets. We shouldn’t think of this as a conflict between using available land to expand forests and growing crops for energy. Both are required,” he adds.

If the carbon balance between the Earth and its atmosphere is to be maintained, the emission of a fossil-sourced CO2 molecule must be compensated for by an increase in the Earth’s non-fossil-based carbon stock or other ways of removing CO2 from the biosphere, regardless of direct CO2 emission mitigation. However, the amount of carbon that can be naturally absorbed by the oceans and terrestrial biosphere is limited, and current emissions are far exceeding this natural sink capacity. That balance is no longer maintained, and the carbon store in the atmosphere has reached critical levels in terms of limiting average world temperature rise. As a result, labelling bioenergy as “bad” is deceptive. Limiting the effects of climate change will necessitate a huge effort, including a substantial reduction in fossil emissions. Bioenergy in isolation cannot solve the climate crisis, but it will play a critical role as part of a larger transformation. “We need integrated and multiple solutions,” adds Cherubini, “that includes forest management, forest development, and forest conservation, as well as simultaneous improvements in the agri-food industry.”

Given the pressing need to cut fossil-fuel emissions, carbon capture and storage (CCS) technology can be used with bioenergy to offer a carbon-negative solution. According to the IPCC, this method alone has the potential to permanently store gigatons of CO2 per year, albeit this is contingent on the availability of sustainable biomass and full-scale CCS implementation. Beyond combustion, there are many additional biomass-based climate-positive options that can help with the energy transition. Storing charcoal in the soil enhances soil quality while also creating a carbon sink, making it a viable choice for both urban and rural settings. Increased use of wood as a construction material will also help to store carbon in the long run.

Biomass and bioenergy should be part of the plan. We need a complete portfolio of sustainable solutions that take into account complicated local situations as well as larger societal needs and energy demands. Therefore, the idea of woody biomass should not be dismissed. Instead, we should concentrate on developing the greatest possible management techniques and regulations for sustainable production.