Bioenergy covers a diverse range of energy sources, and its role in tackling greenhouse gas emissions is hotly debated.
The environmental impact of bioenergy systems vary greatly. However, modern bioenergy production techniques mean sustainable bioenergy moves closer every year.
Let’s look at how the nascent bioenergy industry is working towards greater energy production and helping reduce carbon emissions that cause global warming.
What Is the Definition of Bioenergy?
Bioenergy, as a word, comes from combining biomass (organic matter) with energy. In practical terms, bioenergy is an umbrella term for energy derived from biomass. We use this biomass to make transportation fuels, electricity, heating and cooling, and even products.
The organic biomass comes from living or recently living plants and animals, and waste products. At its most basic, bioenergy began when humans burned wood, releasing its chemical energy to keep warm and cook.
Where Does the Fuel for Bioenergy Originate?
Bioenergy starts with the sun. Plants use photosynthesis to harness the sun’s energy and grow, which we then use.
Animals eat and excrete these plants. We can take the energy from the animals by eating them or using their excretions. Humans have been burning cow dung as fuel for thousands of years and using fire as energy for much longer.
These are the origins of bioenergy, but modern bioenergy is much more advanced.
Is Bioenergy a Renewable Energy Source?
Bioenergy is considered a renewable energy source. The required organic living matter, or biomass, can be regrown and replaced in relatively short periods. Fossil fuels like coal and gas take millions of years to form and are not renewable. However, there are frequent debates about the sustainability of some biomass sources and its future as a renewable resource.
What Are the Various Types of Biomass?
Biomass sources are many and varied. The primary sources include:
- Crops, grasses, and their byproducts and waste
- Timber and wood industry byproducts, like wood chips and wood pellets
- Food and cooking oil waste
- Livestock manure
- Microalgae
- Municipal solid waste, e.g., landfills sites
- Sludge and waste animal fats
Biomass is a mix of waste, unwanted by-products, and making the most of unusual fuel sources like manure and cooking oil.
What Types of Fuel Can We Make With Biomass?
Versatility is the watchword for biomass. It can be converted into many forms of what we call biofuels, which can then be converted into energy. The modern world now enjoys advanced biofuels that can power jet planes and is considered by some to be a renewable energy source for the future.
The most common uses for biomass are:
- Burning to create electricity
- Capturing waste gases to burn for heating or to make electricity
- Converting into liquid transportation fuels, like jet fuel, diesel, or gasoline
- Bioproducts like bioplastics, fertilizers, lubricants, and biofibers
- Biocosmetics, medicines, and industrial chemicals
Bioenergy technologies allow us to reuse various biomasses as biofuels, for energy production, or bioproducts.
How Is Bioenergy Created?
We’ve seen a wide range of bioenergy sources called biomass, and these can be used in many ways. Let’s look in more detail at how we create bioenergy, also, confusingly, called biopower.
Biomass combustion: As early humans did, biomass combustion burns organic material or biomass. We call biomass burned this way “feedstock” with wood the most common source. The heat from burning can warm water and homes and, on an industrial scale, generate steam to create electricity.
Anaerobic digestion: Microorganisms can be sealed in a vessel to digest rotting agricultural waste or any decaying organic material. The byproduct of this anaerobic digestion is methane, called biogas, and carbon dioxide.
The methane biogas can be transported to power plants to be burned to create electricity. Or it’s cleaned then pumped to replace natural gas. Methane can also be purified into biomethane and used as fuel for adapted vehicles.
Gasification: Biomass is incinerated in a “gasifier” and converted into fuel gas. Food scraps, animal products, paper, glass, metal, and even plastics can undergo the gasification process. Oxygen and steam cause chemical reactions to create gas, and no combustion is required.
Fermentation: You might know this process as it relates to beer and wine. But this type of fermentation takes the sugars and starches from crops such as corn and beets and ferments them to create biofuels for vehicles, such as ethanol, methanol, or butanol.
How Does Landfill Waste Create Bioenergy?
Municipal solid waste is the third-largest source of methane that humans produce in the United States. Methane is one of the most potent greenhouse gases, causing up to 25 times more damage than carbon dioxide during its lifetime in the atmosphere.
Landfill sites can be adapted to capture the methane that escapes from rotting garbage. Sealed tanks hold the waste while it breaks down, and the methane is vented and caught. Once burned, the methane produces carbon dioxide and water that can power turbines to create electricity or adapted for use in vehicles.
What Are Biofuels and How Do We Use Them?
Biofuels, or liquid fuels, play an essential role in the use of biomass. We can power most combustion engine vehicles with biofuels made from agricultural and food processing waste, such as corn or leftover cooking oil from restaurants.
Making the most of biomass as biofuels is vital for an automobile-loving nation like the U.S. In 2019, transportation accounted for 29% of the United States CO2 emissions, according to the Department of Energy (DOE).
The two most common biofuels are ethanol and biodiesel. They emit less greenhouse gas emissions and are better at biodegrading than fossil fuel equivalents. The DOE thinks using ethanol as a biofuel could save up to 86% in emissions compared to standard vehicle fuels.
Biodiesel produces about 60% less net-lifecycle carbon dioxide emissions when compared to gasoline. The energy content of biodiesel is about 90% of that of petroleum diesel.
What Are Some Examples of Bioenergy in Action?
So far, we’ve looked at biomass, biofuel types, and how bioenergy is made. Let’s look at some real-life energy uses for bioenergy.
Paper mills have access to vast amounts of biomass fuels, with wood waste material (feedstock) left over from their forestry. Many paper mills make electricity onsite, burning the feedstock to power a generator.
Farmers use biodigesters full of microorganisms that digest cow manure to create methane to generate electricity and heating. Some systems even produce valuable byproducts from the manure, such as bedding for livestock and fertilizer.
Airlines are mixing standard jet fuel with sustainable aviation fuel (SAF) to help clean up their planes’ emissions. SAF is a biofuel made from feedstocks and produces up to 80% fewer lifetime carbon emissions than standard jet fuel.
What Are the Advantages of Bioenergy?
Bioenergy plays a controversial role in the renewable energy sector. The various forms of bioenergy bring many good things to the emissions-cutting table.
Its versatility is one of its foremost attractions, from the range of organic materials that can be processed to the end products. Waste, garbage, and even manure can be reused to open up its stored carbon and even create valuable byproducts.
But burning biomass does release carbon dioxide. Some argue burning biomass releases the same amount of carbon that the organic matter absorbs while growing, so it doesn’t break the carbon balance of the atmosphere.
In contrast, fossil fuels release carbon that has been stored on the Earth for millions of years. Burning fossil fuels adds extra carbon to the world’s current carbon levels and accelerates global warming.
Some biofuels are very energy efficient; a gallon of corn ethanol can deliver up to 67% more energy than required for its production.
Bioenergy can help reduce air pollution, too, by removing methane from the atmosphere. However, burning wood and methane for generating power and heating homes does pollute.
Bioenergy reduces dependence on domestic and imported fossil fuels, promoting energy independence. A country’s power grid benefits from flexible and reliable power sources, of which bioenergy is one. It’s especially important in remote areas that might be off-grid or suffer from power outages.
What Are the Disadvantages of Bioenergy?
Forestry is probably the most controversial topic for biomass. In 2018, solid biofuels like wood pellets, wood chips, and trees, made up 85% of biomass products. Deforestation also occurs across the globe as people in rural communities search for wood for cooking and heating.
Felling forests has several impacts on the environment. It can devastate an area’s biodiversity, wildlife, and ecosystem, representing poor land use. Trees may take 50-100 years to regrow, absorbing less carbon than fully grown trees.
Some wood pellets are made by chopping down trees rather than using waste wood. The European Union imports wood pellets from the United States and those pellets travel across the Atlantic ocean in petroleum-powered boats. It is unknown if any of these pellets come from trees felled for this purpose. Still, the additional transport adds to the biomass’s carbon footprint.
Demand for wood or other biofuel crops varies and alters biomass quality and availability. Clamor for biomass has also pushed up prices for these once-neglected resources.
There are some problematic ethical angles to consider as well. Biofuels consume agricultural waste that previously may have fertilized fields. Energy crops are grown specifically to use as biomass and yet there are 663 million undernourished people worldwide.
Extra crops also bring additional pressure on water supplies and soil quality, especially if just one crop is grown across vast areas. Plus, we can’t escape the fact that bioenergy’s biomass and processes emit greenhouse gases.
What’s the Potential for Bioenergy in the United States?
The U.S. Department of Energy’s 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy set out several scenarios for the bioenergy industry.
By 2040, the report concluded, the United States could produce one billion dry tons of non-food biomass resources annually without affecting food, feed, or fiber supply chains.
Using current bioenergy technology, hitting one billion tons of biomass a year could:
- Generate $259 billion internal trade for the U.S.
- See 1.1 million people working in the bioenergy sector
- Avoid 446 million tons of CO2 equivalent emissions annually
- Reduce fossil fuel consumption by 9.5%
Which Countries Use Biomass Energy?
Countries that use the most biomass energy are mainly in Africa, where many people take wood from forests and savannas for heating and cooking. Ethiopia, DR Congo, and Tanzania head the list, with Nepal, Haiti, and Cambodia among others worldwide.
Modern biofuels figures do not include traditional biomass in their calculations. Under the modern biofuel figures, Europe and the United States use the most wood pellets and solid biofuel, while Europe leads the way in creating energy from waste.
What Is Bioenergy With Carbon Capture and Storage?
Bioenergy with carbon capture and storage (BECCS) deals with the carbon emissions caused by biomass and bioenergy generation.
It works in the same way as standard carbon capture and storage. Carbon is caught at the production point, usually in a furnace or power plant. It is turned into liquid form, then transported and stored underground, often in old coal mines or porous rock formations.
BECCS may make bioenergy processes carbon negative, effectively removing carbon from the atmosphere. Plants used as biomass absorb carbon while growing, and that carbon is released when burned to create biofuels. However, carbon stays captured during production stays out of the atmosphere, offsetting any carbon created when biofuels are used.
How Many Carbon Emissions Does Bioenergy Emit?
Both the price and carbon emissions of bioenergy are challenging to calculate. The many variables include biomass source, process type, location, scale, and more.
One study found bioenergy emissions comparable with hydropower and natural gas once you include lifetime emissions, operation, construction costs for production, effect on land use, and direct emissions. Solar, nuclear energy, and wind energy are the cleanest, and coal is the dirtiest fuel.
Bioenergy tied with carbon capture beats everything hands down because it removes carbon from the atmosphere. Carbon capture can help industries that emit carbon dioxide become carbon neutral by allowing them to carbon offset.
Bioenergy May Become a Popular Tool to Fight Climate Change
Bioenergy is a diverse and fascinating branch of renewable energy. In many cases, it looks like a sensible land and resource management approach that squeezes the most out of available organic matter.
Some bioenergy processes produce low carbon emissions or replace fossil fuels like gasoline or natural gas. However, bioenergy is not a panacea for all greenhouse gas emissions. Collecting biomass can disrupt the environment and produce carbon emissions.
The fight against climate change will involve bioenergy alongside carbon capture, consumers switching to renewable energy sources and green energy plans, government policy, and lifestyle changes. And let’s not forget the humor involved in such a serious topic. There’s a certain satisfaction in thinking that a cow’s flatulence could soon be keeping your home warm and cozy.
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