By
Grace Smoot

Biomass energy is the energy generated from burning or converting organic sources including wood, agricultural byproducts, and waste. It has long been thought of as a sustainable alternative to traditional fossil fuels, but in reality, it may do more harm than good. So, we had to ask: What is biomass energy really, and how can it help mitigate climate change?

Biomass energy is the combustion or conversion of renewable, organic material to release stored energy. Unfortunately, it has high levels of CO₂ emissions and contributes to climate change, air pollution, and deforestation. Overall, it is not as sustainable or beneficial as it might seem.

Keep reading to find out all about what biomass energy is, its global capacity, its carbon footprint, its environmental benefits and drawbacks, and how it can mitigate climate change.

The Big Picture of Biomass Energy

Biomass energy is classified as a renewable energy source because the resource (organic material) naturally replaces itself over time. Biomass is extremely versatile and can be used to produce fuel, energy, and various everyday products. Although some claim it to be an alternative to fossil fuels (e.g., coal, oil, natural gas), biomass energy is not as sustainable as it appears to be at first glance. 

How Is Biomass Energy Defined

Biomass is renewable, organic material derived from plants and animals. 

“Biomass: natural materials from living or recently dead plants, trees and animals, used as fuel and in industrial production, especially in the generation of electricity”

Oxford Dictionary 

To harvest biomass energy, different biomass sources are burned or converted to release stored chemical energy from the sun.

What Are the Different Types of Biomass Energy 

The different sources of biomass energy include:

• Wood and wood processing wastes
• Agricultural crops and waste materials
• Municipal solid waste
• Animal manure
• Human sewage

And these biomass sources can be used to produce the following:

• Biofuels: Biomass is converted into liquid fuel (ethanol or biodiesel) used for transportation. Biofuels include fuels made from crops such as corn, sugarcane, hemp, and cassava.

• Biopower: Biomass fuel is converted into energy via combustion, bacterial decay, or conversion to gas/liquid fuel (biogas).

• Bioproducts: Biomass is chemically converted into plastics, lubricants, and industrial chemicals made from petroleum.

What biomass energy is	Biomass energy is the combustion or conversion of biomass sources to release stored chemical energy from the sun.
What the different types biomass energy are	Biomass can be used to produce biofuels (e.g., ethanol and biodiesel), biopower (via burning, bacterial decay, and conversion to biogas), and bioproducts (e.g., plastics, lubricants, and industrial chemicals).
How biomass energy works	To harness biomass energy, sources of biomass undergo either direct combustion or thermochemical/chemical/biological conversion to release energy stored within the organic material.
The global capacity of biomass energy	Nearly 3 billion people worldwide still rely on the burning of traditional biomass to meet their basic household energy needs.  The global demand for modern biomass is roughly 5 times higher than that of solar and wind energy combined.
The carbon footprint of biomass energy	Regular biomass energy emits 230 gCO2 per KWh and co-firing biomass energy emits 740 gCO2 per KWh, the fourth and second-highest out of all fuel types, respectively.
The environmental benefits of biomass energy	Biomass indirectly benefits the environment by promoting energy independence and creating jobs, but it does not benefit the fight against climate change because of its high carbon footprint.
The environmental drawbacks of biomass energy	Biomass energy has high levels of CO2 emissions and contributes to both air pollution and deforestation. In addition, we are currently using biomass in an unsustainable way.
Biomass energy and climate change	Per KWh, biomass power plants emit 150% of the CO2 of coal and between 300% – 400% of the CO2 of natural gas, making biomass energy a major contributor to climate change.

How Does Biomass Energy Work

To harness biomass energy, sources of biomass are either burned or chemically converted to release stored energy from the sun. 

How Does Biomass Energy Actually Produce Energy

Biomass sources are extracted and converted to energy via the following processes:

• Direct Combustion: The most common method of converting biomass into energy involves directly burning the biomass to heat water, fuel industrial processes, or generate electricity in steam turbines. 

• Thermochemical Conversion: Gasification and pyrolysis, thermal decomposition processes where biomass is heated in a closed and pressurized vessel, are used to produce synthetic gas (syngas) or charcoal, bio-oil, renewable diesel, methane, and hydrogen, respectively. The two processes differ in the temperature and amount of oxygen in the reaction.

• Chemical Conversion: Transesterification is used to convert vegetable oil, animal fat, and grease into fatty acid methyl esters (FAME), producing biodiesel. 

• Biological Conversion: Fermentation is used to convert biomass into ethanol, and anaerobic digestion is used to produce renewable natural gas (biogas/biomethane).

What Is the Global Capacity of Biomass Energy

Biomass energy has been split into two categories, traditional biomass energy and modern biomass energy. Traditional biomass involves the combustion of biomass sources directly to produce energy and heat, whereas modern biomass involves converting biomass sources into gaseous and liquid fuels.

What Is the Global Capacity of Traditional Biomass Energy

Traditional biomass involves burning wood, agricultural by-products, or dung for cooking and heating purposes. 

The share of global primary energy consumption coming from traditional biomass has decreased from 95% in the 1800s to less than 7% in 2022.

Whereas developed countries have transitioned away from traditional biomass, some developing countries still rely on it heavily. Nearly 3 billion people worldwide still rely on the burning of traditional biomass to meet their basic household energy needs, and 2.3 billion still use traditional biomass for cooking.

Countries that continue to rely heavily on traditional biomass include Niger, Kenya, Tanzania, Nigeria, the Democratic Republic of Congo, and Haiti.

What Is the Global Capacity of Modern Biomass Energy

Modern biomass energy includes biogas and biofuels (ethanol and biodiesel). The global demand for modern biomass is roughly five times higher than that of solar and wind energy combined.

Biogas is a gaseous mixture of 45% to 75% methane (CH₄), carbon dioxide (CO₂), and small quantities of other gasses created through anaerobic digestion or thermochemical conversion of biomass in an oxygen-free environment. 

Global biogas production has increased from over 7 billion cubic meters in 2000 to over 38 billion cubic meters in 2020. We currently have over 50 million micro-biodigesters, 132,000 small/medium/large scale biodigesters, and 700 upgrading plants (to produce biomethane) in operation worldwide. Europe, China, and the US account for 90% of global biogas production. 

The potential to generate biogas energy from different biomass feedstocks is great, with sequential crops (multiple crops grown right after another on the same field) providing the greatest GWh of potential energy per ton of material.

We can potentially generate between 10,000 and 14,000 terawatt-hours (TWh) of biogas energy from biomass feedstocks, the equivalent of meeting 6-9% of the world’s energy consumption, 23-32% of the world’s coal consumption, and 16-22% of the world’s electricity consumption. 

Biofuels are alternatives to petroleum fuels that come with lower greenhouse gas emissions. The two most common biofuels used for transportation are ethanol and biodiesel, which are commonly blended with petroleum fuels (gasoline and diesel fuel). 

Global biofuel demand has increased by roughly 6% per year since 2016. In 2022, biofuels accounted for roughly 3.5% of the global transportation energy demand. But we still have a ways to go to meet the 9% target laid out in the Net Zero by 2030 Scenario. 

The US, Brazil, Indonesia, China, and Germany are the five largest biofuel-producing countries in the world, accounting for roughly 75% (900 TWh) of global biofuel production (1,187 TWh).

What Is the Carbon Footprint of Biomass Energy

The carbon footprint is one of the ways we measure the effects of human-induced global climate change. It primarily focuses on the greenhouse gas (GHG) emissions associated with consumption and includes other emissions such as methane (CH₄), nitrous oxide, and chlorofluorocarbons (CFCs).

“Carbon footprint: the amount of greenhouse gasses and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

Basically, it is the amount of carbon emitted by an activity or an organization. This includes GHG emissions from fuel that we burn directly (e.g., heating a home or driving a car) and GHG emissions from manufacturing the products that we use (e.g., power plants, factories, and landfills). 

On a life-cycle basis, regular biomass energy emits 230 grams of CO₂ equivalent per kWh (gCO₂ per KWh), the fourth-highest amount out of all of the fuel types, and the highest amount out of all of the renewable fuel types. 

On a life-cycle basis, co-firing biomass energy, where biomass is added as a partial substitute fuel in coal boilers, emits 740 gCO₂ per KWh, the second-highest amount out of all fuel types and second only to coal. 

Have a look at the illustration below to see the average life-cycle CO₂ equivalent emissions of different energy sources and how they compare to biomass energy.

When discussing the carbon footprint of biomass energy, we must take into account carbon emissions across the energy’s building, operating, and building back phases.

The life-cycle stages of biomass energy	Each stage’s carbon footprint
Building of biomass energy	CO2 emissions from extracting and processing biomass, transportation of biomass on trucks or by rail, construction of biomass power plants
Operating of biomass energy	CO2 emissions from biomass combustion, operation of equipment at biomass power plants
Building back of biomass energy	CO2 emissions from utilizing construction equipment to demolish the buildings and construct new buildings in the old power plant’s place

How Environmentally Friendly Is Biomass Energy

Biomass energy is a major fuel source in developing countries and is used widely to produce biofuels, but the combustion of biomass sources produces large quantities of CO₂ . 

“Environmentally friendly: (of products) not harming the environment.”

Cambridge Dictionary

Biomass is often portrayed as an alternative to fossil fuels with CO₂ reduction benefits. However, biomass still possesses environmental drawbacks that must be taken into consideration, along with the benefits.

What Are the Environmental Benefits of Biomass Energy

The environmental benefits of biomass include:

1. Energy independence: Being able to produce your own electricity without the aid of foreign countries is an important step in becoming more self-sufficient. Former President George W. Bush signed the Energy Independence and Security Act of 2007 to reduce U.S. dependence on oil, expand the production of renewable fuels (and confront global climate change). 

2. Employment opportunities: The renewable energy sector employed over 13.7 million people worldwide in 2022. Renewable energy jobs continue to increase as we start to realize just how beneficial renewable energy is for our environment. 

Biomass indirectly benefits the environment by promoting energy independence and creating jobs, but it does not benefit the fight against climate change because of its high carbon footprint.

What Are the Environmental Drawbacks of Biomass Energy

Although biomass is a renewable energy source that is often referred to as a better option than fossil fuels, it still has drawbacks which include:

• CO₂ emissions: Existing biomass power plants can emit more CO₂ from their smokestacks than coal plants because wood is less energy-dense than coal and therefore requires more wood to generate the same amount of electricity as a small amount of coal can. Replacing coal with biomass inevitably releases more CO₂ into the atmosphere.

• Air pollution: Developed countries that burn organic matter for heat and cooking release particulate matter (PM), carbon monoxide (CO), hydrocarbons, oxygenated organics, free radicals, and chlorinated organics. All of these can cause respiratory infections such as pneumonia, tuberculosis, and chronic obstructive pulmonary disease, as well as low birth weight, cataracts, cardiovascular events, and death.

• Deforestation: Our forests absorb 2.6 billion tons of CO₂ every year. The main threat to them is deforestation, which occurs at roughly 10 million hectares (~ 25 million acres) per year. The world has lost more than 1/3 of its forest since the last ice age, which occurred about 2.6 million years ago. Trees combat climate change, purify the air, provide housing for millions of plant and animal species, protect against floods and water pollution, and improve mental health. Chopping trees to produce wood pellets that are then burned for electricity has a devastating effect on the environment because it reduces the number of trees that can capture our CO₂ emissions. Protecting forest habitats increases carbon sequestration. 

In addition, although biomass is a renewable energy source, it is not a sustainable energy source. Overall, biomass is not as sustainable as it appears to be at first glance. For biomass to be sustainable, the rate of harvest must not exceed the rate of forest growth. In reality, this rarely happens. Also, it could take anywhere from decades to well over a century before we start receiving the climate benefits provided by biomass, which is well outside the timeframe of averting our current climate crisis.

In short, the easiest way to mitigate the environmental impact of biomass is to simply not rely on it in the first place. Biomass pollutes the air, leads to deforestation, and is not a sustainable energy source. Its combustion also adds to atmospheric CO₂ levels and contributes to global warming.

How Does Biomass Energy Contribute to Climate Change

Climate change is arguably the most severe, long-term, global impact of fossil fuel combustion. Every year, approximately 36 billion tons of CO₂ are emitted from burning fossil fuels. And, per kilowatt-hour (KWh), biomass power plants emit 150% of the CO₂ of coal and between 300% – 400% of the CO₂ of natural gas, making them a major contributor to climate change. The carbon found in biomass reacts with oxygen in the air to produce CO₂. This warms the earth by acting as a heating blanket, and a warmer earth comes with a host of negative side effects. 

The CO₂ emissions associated with biomass energy contribute to climate change in the following ways:

• Increasing temperatures: Earth’s atmosphere has warmed 1.5°C since 1880. This may not seem like a lot, but these degrees create regional and seasonal temperature extremes, reduce sea ice, intensify rainfall and drought severity, and change habitat ranges for plants and animals.

• Rising sea levels: Global sea levels have increased approximately 8-9 inches since 1880, displacing people living along coastlines and destroying coastal habitats. Roads, bridges, subways, water supplies, oil and gas wells, power plants, sewage treatment plants, and landfills remain at risk if sea level rise goes unchecked. 

• Melting of sea ice: Since 1979 arctic sea ice has declined by 30%. Sea ice plays a major role in regulating the earth’s climate by reflecting sunlight into space and providing habitat for animal species. If all of the glaciers on Earth melted, sea levels would rise by approximately 70 feet, effectively flooding out every coastal city on the planet. 

• Changing precipitation patterns: Extreme weather events (e.g., hurricanes, floods, droughts) are becoming more common and more intense. Storm-affected areas will experience increased precipitation and flooding whereas areas located further from storm tracks will experience decreased precipitation and droughts.

• Ocean acidification: The ocean absorbs 30% of the CO₂ released into the atmosphere, which decreases the pH (increases the acidity) of the ocean. In the past 200 years, the pH of oceans has decreased by 0.1 pH units, which translates to a 30% increase in acidity. Aquatic life unable to adjust to this rapid acidification will die off. A prime example of this is coral bleaching, where coral expels the algae (zooxanthellae) living in their tissues as a result of changes in temperature, light, or nutrients. 

The more we reduce CO₂ emissions, the more we slow the rate of temperature rise, sea-level rise, ice melting, and ocean acidification. When these rates are slowed, the earth’s biodiversity does not have to struggle to adapt to temperature and pH changes. People will not be displaced due to the flooding of coastal areas. And icebergs will continue to provide climate regulation. 

To help keep global temperature rise below 1.5°C, as outlined in the Paris Agreement, we must shift at least 80% of our electricity generation to low-carbon sources. Over 140 countries have stated a net-zero target, covering roughly 88% of the world’s emissions. However, under current conditions, global emissions are projected to increase by 9% by 2030 instead of the 45% reduction in emissions that is needed.

Final Thoughts

Biomass is the renewable, organic material derived from plants and animals that can be used to produce biofuels (e.g., ethanol and biodiesel), biopower (via burning, bacterial decay, and conversion to biogas), and bioproducts (e.g., plastics, lubricants, and industrial chemicals). 

Biomass energy has been split into traditional and modern biomass energy. Whereas developed countries have transitioned towards modern biomass energy (biogas and biofuels), some developing countries still rely heavily on traditional biomass for cooking and heating. Meeting the goals established in the Paris Agreement involves transitioning to modern biomass energy.

Biomass is often portrayed as an alternative to fossil fuels because it is a renewable energy source that uses organic matter as fuel. Biomass benefits the environment by creating jobs and promoting energy independence; however, it is an unsustainable energy source whose combustion produces more CO₂ than conventional coal power plants and causes air pollution and deforestation. Because of this, the environmental benefits are scarce and the drawbacks abundant. 

Stay impactful,

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