What Is The World’S Most Used Source Of Bioenergy?

Bioenergy refers to renewable energy derived from organic matter, known as biomass. Sources of biomass include wood, agricultural residues, animal manure, municipal solid waste, and landfill gas. Bioenergy is considered a renewable energy source because the carbon in biomass is part of the natural carbon cycle. As plants grow, they absorb carbon dioxide from the atmosphere and convert it into biomass. When biomass is burned for energy, it releases the carbon absorbed by the plants back into the atmosphere. The use of bioenergy is increasing globally as countries seek to expand their renewable energy portfolios and reduce greenhouse gas emissions. This article will examine the major sources of bioenergy and determine which is the most widely used globally.

Wood and Wood Waste

Wood and wood waste refers to wood sourced from forests as well as residues from wood processing industries. This includes sawdust, cutoffs, shavings, and bark. Wood and wood waste can be directly burned to produce heat and electricity or can be processed into wood pellets, chips, or bio-oils for energy production.

According to the Global Bioenergy Statistics report, wood fuel accounted for over 50% of total primary bioenergy supply globally in 2020, making it the world’s most used source of bioenergy ^[1]. 1.9 billion cubic meters of wood fuel was used globally for energy in 2020. The United States is the largest consumer of wood and biomass waste, using over 370 million dry short tons in 2020 ^[2]. Other major consumers include Brazil, China, India, and countries in Europe.

Agricultural Residues

Agricultural residues refer to the plant material left over after harvesting crops. This includes field residues like straw from grains crops and processing residues like husks, cobs, and bagasse. Agricultural residues can be used as feedstocks for bioenergy production through direct combustion, gasification, pyrolysis or anaerobic digestion.

According to the European Technology and Innovation Platform on Bioenergy, 139 million tonnes of agricultural residues are produced annually in the EU, with the potential to produce up to 11,000 ktoe (kilo tonnes of oil equivalent) of second generation biofuels [1]. Globally, agricultural residues account for around 10-15% of total primary bioenergy production [2]. While agricultural residues present an opportunity for renewable bioenergy, their use must be balanced with maintaining soil quality and preventing erosion.

Animal Manure

Animal manure is a significant source of biomass that can be used for bioenergy production. Manure contains organic matter that can be converted into biogas through a process called anaerobic digestion. During anaerobic digestion, bacteria break down manure in an oxygen-free environment, producing a gas composed primarily of methane and carbon dioxide.

According to a study, biogas plants using only animal manure produced 12.4% of the total electricity from biogas worldwide in 2016. The amount of manure produced globally is estimated at billions of tons per year. In the United States alone, livestock animals generate over 1 billion tons of manure annually. Converting this waste into energy can provide a reliable source of power while also managing waste from animal agriculture.

Burning the biogas generated from manure is also cleaner than directly emitting raw manure’s methane into the atmosphere. Capturing the energy helps reduce greenhouse gas emissions. Overall, animal manure represents a significant opportunity to generate bioenergy and make progress toward renewable energy goals globally.

Municipal Solid Waste

Municipal solid waste (MSW), commonly known as trash or garbage, refers to everyday items we use and then throw away, such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, and batteries. MSW contains biomass materials like paper, yard trimmings, food waste, and wood that have caloric value and can be converted into useful energy through various processes.

According to the U.S. Energy Information Administration, over 25 million tons of MSW biomass was used for energy in the United States in 2019. This accounted for about 13% of total MSW generated that year. Globally, waste-to-energy plants process around 300 million tons of MSW annually, generating over 550 billion kilowatt-hours of electricity, enough to power over 50 million homes. The European Environment Agency reports at least 480 operational MSW waste-to-energy plants across Europe as of 2019. In Japan, over 40 million tons of MSW is processed in over 1,200 waste-to-energy plants, generating around 14 billion kWh annually (EIA).

Landfill Gas

Landfill gas (LFG) is produced as organic waste decomposes in landfills. It is composed of roughly 50% methane, 50% carbon dioxide, and trace amounts of non-methane organic compounds. Methane is a powerful greenhouse gas, and landfills are a major anthropogenic source, accounting for approximately 15% of global methane emissions according to the EPA (source).

To reduce methane emissions and produce renewable energy, many landfills around the world now collect LFG through a network of wells and pipes buried in the landfill. The gas is then treated and used to generate electricity or steam, replace fossil fuels in industrial and manufacturing operations, or upgrade it to pipeline-quality renewable natural gas. According to the EPA, there are approximately 685 operational LFG energy projects in the U.S. and over 1,000 projects globally (source).

The Global Methane Initiative estimates that LFG energy projects generate over 14,000 megawatts of electricity around the world, providing a significant contribution to global bioenergy production. The EPA found that in 2020, LFG energy projects in the U.S. generated over 15 billion kW hours of electricity, which is comparable to powering over 1.5 million average American homes for a year (source). Collecting methane for energy instead of letting it escape into the atmosphere provides major climate benefits and advances progress toward carbon neutrality goals.

Comparison

Wood and wood waste is by far the most used source of bioenergy globally. According to the sources(1), wood accounts for about 50% of total bioenergy usage worldwide. The next most used sources are agricultural residues (17%), animal manure (9%), and municipal solid waste (6%)

While developing nations rely more on traditional biomass like wood, animal dung and agricultural residues, developed nations utilize modern bioenergy sources like municipal solid waste and landfill gas more. However, wood remains the dominant source across both developing and developed regions.

Wood’s prominence can be attributed to its widespread availability and relative ease of use as an energy source, especially for heating and cooking needs. Plant biomass requires less processing compared to waste sources. Additionally, wood can be harvested directly from forests or obtained as a byproduct from lumber mills and other wood-product industries.(1)

All in all, wood and wood waste has emerged as the world’s most utilized source of bioenergy by a considerable margin.

(1) https://quizlet.com/237283855/chapter-20-flash-cards/

Growth Trends

The global bioenergy market is projected to grow at a CAGR of 5.4% from 2022 to 2031, reaching $246.52 billion by 2031 according to a report by Market Reports World Bioenergy Market 2023-2031. Wood and wood waste is expected to remain the dominant source of bioenergy during this period. Factors driving growth include rising energy consumption, favorable government policies, and a shift toward renewable energy sources. However, growth in agricultural residues and biogas is projected to outpace wood bioenergy. The share of bioenergy from agricultural residues is estimated to grow from 25% in 2022 to 28% in 2031. Similarly, biogas from landfills and animal manure is expected to see rapid growth as more facilities come online. Overall, wood and wood waste will likely remain the top source of bioenergy through 2031, but its market share will gradually decline as other sources gain traction.

Environmental Impact

The world’s leading bioenergy source, wood and wood waste, has both positive and negative environmental impacts. On the positive side, using wood biomass emits lower levels of sulfur oxides, nitrogen oxides, and particulate matter compared to fossil fuels like coal (1). Wood biomass is also considered carbon neutral since the carbon released during combustion is recaptured as new trees grow. This helps mitigate climate change impacts (2).

However, there are also downsides. Harvesting large amounts of wood can lead to deforestation and habitat loss. The use of fertilizers and pesticides in growing biomass crops can cause water pollution. Burning wood biomass still emits carbon dioxide, even if it is later recaptured. There are also concerns that dedicating more land to growing bioenergy crops could compete with food production and raise food prices (3).

The continued dominance of wood biomass is likely not sustainable long-term given its potential to spur deforestation and impact biodiversity. Usage may need to shift toward agricultural residues and waste products that do not require dedicated land and resources. Better forest management practices and agricultural techniques can help mitigate the environmental tradeoffs of wood biomass (1). But ultimately, bioenergy should be just one part of a broader renewable energy mix rather than the primary global energy source.

Conclusion

Wood and wood waste is the world’s leading source of bioenergy for good reason. As an abundant, carbon-neutral renewable fuel, wood has served as an important energy source for centuries, and continues to do so today. As the dominant global source of bioenergy, wood and wood waste offers a sustainable, low-cost fuel that helps reduce reliance on fossil fuels while providing substantial energy for heat, electricity and transportation fuel. With continued advances in technology and sustainable forest management, wood’s outlook as a steady renewable energy contributor remains bright.

Wood and other woody biomass sources have natural advantages that make them primed to stay at the forefront of bioenergy supply. Their widespread availability, low cost, and established infrastructure for collection, processing and distribution means wood will likely maintain its number one position as the most used source of bioenergy globally. Though other renewables like solar and wind are growing quickly, biomass and woody sources specifically will continue to play a key role in the world’s energy supply.