Bioenergy and carbon capture: The double blow to the climate crisis.

Introduction

The climate crisis currently represents one of the greatest challenges facing our society. Greenhouse gas emissions from burning fossil fuels are the main drivers of climate change. However, bioenergy and carbon capture have emerged as two very important alternative solutions to reduce and control this global problem. These technologies can work together to reduce carbon emissions and offer a promising alternative to transform the energy industry and address the climate crisis.

What is bioenergy?

It is the energy from the transformation of biomass or renewable organic material derived from trees, agricultural crops, forest residues, animal residues and other biological materials. It can be used as an energy source through various processes, such as direct combustion, biogas production or obtaining liquid biofuels . Figure 1 shows a schematic of a biogas plant ² .

Bioenergy classification

Bioenergy will be classified according to the origin of its raw materials as follows:

• From food crops, such as corn, sugarcane and corn for ethanol, and biodiesel feedstock comes from vegetable oils such as soybean oil and canola oil or recycled.
• Created from cellulosic materials such as cotton, wood, herbs and vegetable fibers.
• Energy production that comes from algae.

The importance of biomass in the fight against the climate crisis

• Reduction of greenhouse gas emissions: When used as an energy source, biomass emits carbon dioxide (CO₂), but this amount is equivalent to what forests and plants absorbed during their growth. Therefore, burning biomass does not increase net CO₂ emissions into the atmosphere, making it a cleaner alternative to fossil fuels.

• Fossil fuel substitution: Biomass can be used as a replacement for fossil fuels such as coal, oil and natural gas in various energy applications, such as electricity generation and heating. By reducing dependence on fossil fuels, the emission of greenhouse gases is reduced and it contributes to the mitigation of the climate crisis.

• Waste use: Biomass can come from organic waste, such as agricultural, forestry or food waste, which could otherwise end up in landfills and emit methane, a potent greenhouse gas. By using this waste to generate energy, its decomposition is prevented and the release of methane is reduced.

• Carbon Cycle: Unlike fossil fuels, whose burning releases carbon stored for millions of years in the form of CO₂, biomass comes from plants that have recently captured CO₂ from the atmosphere through photosynthesis. By using biomass as an energy source, a carbon cycle is established in which the CO₂ emitted is reabsorbed again by the new plants, thus maintaining a balance in emissions.

What is carbon capture?

Carbon capture is a process for the collection and retention of carbon dioxide (CO₂) from industrial emissions. The main objective is carbon capture to reduce the concentration of greenhouse gases in the atmosphere and mitigate climate change.

Although it is a technology in full development, there are multiple active projects with scientific / economic support in different countries. Some of these projects are already in operation, with very good results and better projections.

Capture methods and technologies

There are different capture techniques, the most common being:

• Planting trees is the very important way to capture CO₂ (Figure 2): Trees capture carbon through a process of photosynthesis, where tree leaves take carbon dioxide (CO₂) from the atmosphere and, using energy from the sun, convert it into sugars and other organic compounds . These compounds are used for the growth and development of the tree.

That is why the conservation and expansion of forests, as well as reforestation, are fundamental measures to help combat climate change and maintain the balance of the carbon cycle ¹ .

Carbon capture in industrial facilities: It is used in power facilities and other industries to capture the CO₂ produced during the burning of fossil fuels. The CO₂ is separated and stored in underground tanks or used for other purposes.

Direct carbon capture from the air: Involves the capture of CO₂ directly from the atmosphere through chemical absorption with an amine, adsorption with solid materials, such as: zeolites or activated carbon, with the use of membranes that allow the passage of CO₂ while blocking other components of the air and electrochemical capture that uses an electrochemical reaction where, CO₂ is converted to a stable chemical form that can be collected and stored.

What to do with the captured carbon?

The carbon that is captured in order to mitigate the greenhouse effect and managed in different ways.

• Geologic Storage: Captured carbon can be compressed and transported to such as depleted oil or gas reservoirs, saline aquifers, and deep geological formations. There, it is safely injected underground and stored for the long term.

• Use in industry: As raw material in various industrial processes. For example, it can be used for the production of synthetic fuels, chemicals or building materials.

• Battery factory: Captured carbon can be turned into black carbon, carbon nanotubes, or graphene. These forms of carbon have unique properties that can be useful in making batteries.

• Product manufacturing: To manufacture products that have a long useful life. This could include the production of plastics, composite materials, or construction products.

• Use in agricultural products: To improve soil quality and increase carbon sequestration in agriculture. For example, use it in the form of biochar (charcoal) to improve soil fertility.

Synergy between bioenergy and carbon sequestration

Bioenergy and carbon capture are complementary technologies that can work together to address the climate crisis more effectively. Carbon capture can be applied in bioenergy generation plants, where carbon emissions can be safely captured and stored. This allows bioenergy to be an energy source with net negative emissions, since more carbon is removed from the atmosphere than is emitted during its generation process.

Furthermore, bioenergy can provide a constant and reliable source of energy to fuel carbon capture processes. Renewable energy generated from biomass can power carbon capture and storage systems, making this process more efficient and sustainable.

Implementation in the energy industry

The implementation of bioenergy and carbon capture in the energy industry presents a real and promising possibility. Biomass-fired power industries can replace coal and gas plants, dramatically reducing carbon emissions in the power sector. At the same time, the capture of carbon in the bioenergy generating facilities would make it possible to further offset emissions and move towards a cleaner energy matrix.

In addition, bioenergy and carbon capture can play an important role in decarbonizing emission-intensive industries such as steel, oil, gas, cement, and chemical production. These technologies offer a viable solution to reduce emissions in these sectors and contribute to the transition towards a low carbon economy.

Conclusion

Bioenergy and carbon capture are two alternative solutions to address the climate crisis and reduce greenhouse gas emissions. These technologies work together to offer a realistic and sustainable alternative to today’s energy industry. By harnessing the ability of bioenergy to capture carbon and provide a renewable energy source, we can move towards a low carbon economy and mitigate the impacts of the climate crisis. The implementation of these innovative solutions is critical to building a cleaner and more sustainable future for generations to come.

References

1. Source: https://www.infobae.com/america/medio-ambiente/2023/03/26/que-es-y-como-funciona-la-captura-de-carbono/
2. https://autoconsumo.minenergia.cl/?page_id=80