Bioenergy has long been heralded as a sustainable alternative to fossil fuels. However, the reality of bioenergy production and consumption is more complex and nuanced than its clean, green image suggests. This article explains the ecological implications of traditional biomass burning, and the potential of second-generation bioenergy technologies.
- Biofuels and sustainable biofuels are two different things, according to experts.
- Biofuels come from crops like sugarcane, corn, and soybean. These crops are grown specifically for biofuel production.
- On the other hand, sustainable biofuels are derived from waste materials. These include agricultural waste, used cooking oil, and processed animal fats.
- People often use the terms 1G ethanol and first-generation biofuel to refer to biofuels.
- Sustainable biofuels, in contrast, are known as 2G or second-generation biofuels.
- The difference between biofuels and sustainable biofuels has become important due to climate change.
- There are concerns about food security risks and more loss of forests and biodiversity. These are linked to the increased land needed for biofuel crop farming.
Seeking Alternatives To Crude Oil: The Rise of 2G Ethanol
- The Ukraine war has caused severe disruptions to global crude oil supplies.
- Many countries, including India, are urgently seeking alternatives to their reliance on imported petrol and diesel.
- India imports 87% of its crude oil, a major expenditure in its reserve currency.
- Around a quarter of global carbon emissions come from the transport sector.
- As a result, efforts to decarbonize transport have increased.
- Many countries are launching battery production and electric vehicle (EV) policies.
- Legacy automakers are now entering the thriving EV sector.
- However, certain transport modes like aviation, shipping, and long-haul trucking may struggle to reduce their carbon emissions.
- These sectors may find it harder to cut emissions compared to self-driven cars or motorbikes.
- Experts suggest that 2G ethanol could be a viable alternative in these cases.
Bioenergy And Its Impact
- A large portion of vegetated land, over half, is currently in use for cultivation.
- Agriculture is a major contributor to global carbon emissions.
- Utilising corn for fueling vehicles and burning wood for electricity may appear beneficial for reducing reliance on fossil fuels and addressing climate change.
- However, not all forms of bioenergy are beneficial.
- Allocating land specifically for bioenergy production is not a prudent choice.
- This practice takes up land needed for food production and carbon storage.
- Producing a small amount of fuel requires large expanses of land.
- Furthermore, this method is unlikely to significantly reduce greenhouse gas emissions.
The Impact Of Bioenergy Production On Land Use
- Bioenergy production leads to an increase in land competition.
- Currently, about 75% of the world’s vegetated land is used for our food and forest product needs.
- By 2050, the demand for these resources is expected to increase by at least 70%.
- The remaining land houses natural ecosystems that contribute to carbon storage, water protection, and biodiversity preservation.
- The existing land and its vegetation already provide these crucial benefits.
- Hence, using land for bioenergy production, even if it’s underused or degraded, results in a trade-off.
- We may sacrifice the production of vital resources such as food, timber, and carbon storage.
Bioenergy’s Land Inefficiency
- Photosynthesis is an effective way to convert sunlight into food.
- However, it proves inefficient when transforming solar energy into non-edible energy.
- A considerable amount of land and water is needed to produce a minimal amount of plant-based fuel.
- According to a WRI working paper, to provide 10% of the global liquid transportation fuel by 2050, we would need almost 30% of the energy contained in the current annual worldwide crop production.
- The bioenergy demand is not limited to transportation fuels but also includes the use of trees and other biomass for electricity and heat generation.
- Some studies propose that by 2050, bioenergy could fulfil 20% of the world’s total annual energy demand.
- However, this would need a number of plants equal to all the present global crop harvests, plant residues, timber, and grass consumed by livestock, an unrealistic expectation.
Land-based Bioenergy & Greenhouse Gas Emissions
- Bioenergy, specifically when it requires dedicated land use, is not effective in reducing greenhouse gas emissions.
- When biomass (like wood, ethanol, or biodiesel) is burned, it emits carbon dioxide, similar to fossil fuels.
- In reality, burning biomass emits slightly more carbon dioxide compared to fossil fuels for the equivalent energy generation.
- Some calculations suggest bioenergy reduces greenhouse gas emissions because they do not consider the carbon dioxide released during biomass burning.
- This is because they assume that the carbon dioxide released during burning is counterbalanced by the carbon dioxide absorbed by the plants that grew the biomass.
- However, if the plants used for biomass were already growing, repurposing them for bioenergy doesn’t absorb additional carbon from the atmosphere, and therefore doesn’t offset the emissions from burning the biomass.
- The situation worsens when natural forests are cut down for bioenergy production, or to replace farm fields used for growing biofuels, increasing greenhouse gas emissions.
Exploring Second-Generation Bioenergy Technologies
- Bioenergy alternatives exist that do not contend with food or land resources, and substituting these for fossil fuels could cut down greenhouse gas emissions.
- Biomass grown beyond regular requirements due to bioenergy demand, such as winter cover crops for energy, is one such example.
- Other examples include wastes from timber processing, urban waste wood, methane from landfills, and minimal agriculture residues.
- Utilisation of second-generation technologies can assist in transforming materials like crop residues into bioenergy. This approach sidesteps land competition.
- The challenge is to implement this at a large scale. Considerations include existing usage of these residues for animal feeding or soil fertility, and the high costs associated with harvesting certain residues.