Biomass is organic material that can be used to generate heat, electricity, and even fuel. In this lesson, you will learn about the advantages of this abundant and renewable energy source as well as the disadvantages.
It doesn't come as a surprise to anyone that our modern world consumes a lot of energy. We rely on it to get out of bed on time, cook our food, heat our homes, fuel our vehicles, and to power a whole host of conveniences.
Most developed countries, like the United States, rely on non-renewable fossil fuels, such as oil, coal, and natural gas, for energy. However, burning fossil fuels releases greenhouse gases, which are gases in the atmosphere that can trap heat. Also, because they are non-renewable, they will eventually run out.
We are so dependent on energy that I bet you would agree that it would be wonderful if it simply grew on trees. Well, good news! It does. We can create heat, electricity, and fuel from things such as plants, trees, and even organic waste materials.
In this lesson, you will learn how biomass can be converted into a clean and renewable energy source. Biomass is organic materials, including plants and animal wastes. This term is easy to recall if you remember that the prefix bio refers to living things, like plants and animals. Biomass energy, therefore, is energy derived from organic materials.
Now, we know that plants and trees use sunlight to make carbohydrates from carbon dioxide and water using the process of photosynthesis. This energy from the sun gets stored in the plants and transferred to any animal that eats the plants, which is why we can use plants and even animal wastes, like manure, to make biomass energy. When these sources are burned or decompose, they release carbon dioxide and water along with their stored energy.
There are many types of plants and organic wastes that can be used to produce energy. Energy crops, which are sometimes referred to as 'power crops,' are crops grown to be used as fuel, not food. These are generally high-yielding crops, trees, and grasses that require very little care and can be grown at a low cost.
Organic waste from industries such as forestry, agriculture, and manufacturing can be used as a source of biomass energy. Biomass is so versatile that waste generated in cities and urban life, such as old shipping pallets, construction site wastes, and yard wastes, can be used.
Using biomass for energy is nothing new. From the earliest days, man has been burning wood, a form of biomass energy, to cook food and stay warm. Today, biomass is still used for these purposes, but it can also be converted into a gas or oil to generate heat or electricity and even fuel for transportation needs.
Converting Biomass to Energy
Now, there are several ways to convert biomass into energy. The simplest way to use biomass is to burn it. Biomass can be burned in boilers to produce steam. This high-pressure steam is then used to spin a turbine that ultimately generates electricity.
Although burning biomass by itself is a proven method of energy production, it can be inefficient. A process known as co-firing can be used to improve energy efficiency when biomass is burned. Co-firing is defined as burning two forms of fuel simultaneously. Traditional power plants can combine biomass with coal and burn them at the same time. With co-firing, less coal is required, thereby reducing emissions of greenhouse gases.
Biomass does not have to be burned to be converted to energy. When biomass is heated in a low-oxygen environment, it can be broken down and refined to produce fuel gas, such as methane gas. This process of converting organic material into gas is known as gasification. The gas that is produced can be captured and used in gas turbines and other systems to generate electricity. Gasification is more efficient than burning biomass and results in even lower emissions of greenhouse gases.
Another way biomass can be converted into energy is through fermentation. Fermentation is the process of breaking down carbohydrates using bacteria, yeasts, or enzymes. Fermentation is the process most people think of that turns grapes into wine, but biomass liquids can also be fermented, which converts the biomass to alcohol, a type of fuel. In a similar fashion, corn can be turned into ethanol, which is a type of biofuel, or fuel made from biomass. Ethanol can be mixed with gasoline and used for our transportation needs.
Pros of Biomass Energy
There are many advantages to using biomass for energy. Biomass is a type of renewable energy, which means that it can be naturally regenerated.
It's also an abundant source of energy. Not only can we grow crops specifically for energy, but we can also utilize organic wastes that might otherwise simply rot or end up in a landfill.
Biomass is said to be carbon neutral, because the amount of carbon dioxide released into the atmosphere is equal to the carbon dioxide removed from the atmosphere. We learned earlier that plants absorb carbon dioxide during the process of photosynthesis. When these plants are burned or decompose, they release the carbon dioxide, resulting in a net-zero emission.
Biomass also reduces a country's dependence on imported oil, which can be unpredictable, and provides a new source of revenue for farmers.
Cons of Biomass Energy
There are many benefits to biomass, but there are also disadvantages to using biomass for energy. Because biomass is not yet widely used, there is an initial cost barrier. The initial costs for the technology and equipment needed to convert biomass to energy remains high.
Biomass is also bulky, so there are costs involved in storing and transporting large amounts of biomass to energy plants. It is also worth noting that the trucks and other forms of transportation that carry biomass to the energy plants likely run on fossil fuels. Therefore, the source of biomass must be close to the plant or the energy savings is negated.
Even though biomass is considered to be carbon neutral, there are some environmental concerns with its use. If these gases are not captured, they are released into the atmosphere.
Also, because many of the crops used for biomass energy production are also food crops, such as corn and sugar cane, there could be a competition for crops as our world population continues to grow.
Let's review. Biomass energy is the term used for energy derived from organic materials such as plants, trees, grasses, and organic wastes. When you have crops grown to be used as fuel, not food, they are referred to as energy crops. There are several ways to convert biomass into energy.
It can be burned on its own to produce steam to power electricity generation, or it can be burned simultaneously with another fuel source, such as coal, in a process called co-firing.
Biomass does not have to be burned; it can be heated in a low-oxygen environment using a process called gasification, which converts organic material into gas. The gas is then used in gas turbines and other systems to generate electricity.
Fermentation is another way biomass is converted to energy. Fermentation is the process of breaking down carbohydrates using bacteria, yeasts, or enzymes. This process results in alcohol, which is a type of fuel. Any type of fuel made from biomass is called biofuel.
There are many advantages to using biomass for energy. Biomass is a renewable energy source and an abundant source of energy. It is said to be carbon neutral because the amount of carbon dioxide released into the atmosphere is equal to the carbon dioxide removed from the atmosphere from its own growth. Biomass also reduces a country's dependence on imported oil and provides new sources of revenue for farmers.
The disadvantages to using biomass for energy include the fact that there is an initial cost barrier as well as costs involved in storing and transporting large amounts of biomass. Even though biomass energy is carbon neutral, there are some environmental concerns due to other greenhouse gas emissions as well as concerns that there could be a competition for crops as a source of food or fuel.
After this lesson, you'll be able to:
- Define biomass energy
- Describe three ways that biomass can be converted to energy: co-firing, gasification and fermentation
- Explain some advantages and disadvantages to using biomass for energy