In the guide below, we explain what biomass, biofuel, and bioenergy are.
We provide definitions, and discuss how they’re made, what they’re used for, the different types (with examples), plus other relevant information.
What Is Biomass? (Definition)
Biomass is organic material
Some reports indicate it primarily comes from plants and algae
Other reports indicate that some biomass comes from some animal sources too
It’s commonly referred to as being renewable (as opposed to being non renewable like fossil fuels)
Where Does Biomass Come From?
There might be three main sources where biomass comes from:
1. From edible food crops and plants
2. From non edible organic material like residues and waste
3. From algae (and microalgae)
Different Types Of Biomass, & Examples
One report from wikipedia.org indicates that ‘There are five general categories of biomass: industrial waste and co-products, food waste, agricultural residues, energy crops, and virgin lumber’
However, this is just one way to categorise the different types of biomass.
Another way to categorise the different types of biomass, with examples, include but aren’t limited to:
Edible Food Crops
wikipedia.org indicates that ‘The main food crops harvested for energy are sugar-producing crops (e.g. sugarcane), starch-producing crops (e.g. corn) and oil-producing crops (e.g. rapeseed)’
Other examples can include soybeans, grassy crops, and woody plants
The crop/plant material itself can be utilized, but vegetable oils and fats can also be extracted from crops and plants, and then used
Non Edible Organic Material (Residues & Waste)
– Wood residues & wood waste
Might come from leftover wood and residue from forestries
Might also come from wood processing waste in the form of offcuts, wood chips, sawdust, and so on
– Agricultural residues and waste
Such as crop residue waste, and food processing waste
Animal manure may also be used
Animal fats may also sometimes be used from ‘leftover’ carcasses after slaughter
– Municipal and industrial waste
Human waste (such as sewage)
Waste from factories and mills (such as pulp and paper mills)
And, organic materials from municipal waste like cotton, wool, yard trimmings and garden waste, food wastes, and so on
Algae (& Microalgae)
Used specifically for biofuel
Algae is considered the ‘third generation’ of biofuel, after first generation edible crops, and second generation non edible organic materials like residues and waste
What Is Biomass Used For?
Biomass is versatile and can converted into a range of products.
A few of the key uses for biomass can include:
Specifically for electricity, but also for heat
In developing regions of the world, wood is used widely for heating and cooking
With one example being biodiesel
-Biomass used to make commodities and ‘bioproducts’
Biomass can partially or fully replace fossil fuel feedstock in different ‘bioproducts’
energy.gov explains that: ‘[Biomass can serve as a] renewable alternative to fossil fuels in the manufacturing of bioproducts such as plastics, lubricants, industrial chemicals, and many other products currently derived from petroleum or natural gas’
– *A Note About Biomass & Energy Generation
Energy from biomass comes from the chemical energy stored in plants (in the form of glucose or sugar), which has been converted from energy from the sun via the process of photosynthesis
Direct Use Of Biomass vs Conversion Of Biomass
Biomass can be used directly, or converted into different products:
1. Direct Use Of Biomass
This is where biomass is used without processing or refinement.
A good example is burning or combusting wood for heat
2. Conversion Of Biomass Into Different Products
This is where biomass is processed or refined to make ‘bio’ products.
There’s three main types of conversion:
Biological Conversion (also called biochemical conversion)
What Are Biofuels? (Definition)
Biofuels are fuels derived from biomass
What Are Biofuels Used For?
Biofuels are primarily used as a substitute fuel for petroleum in transportation for vehicles
How Are Biofuels Made?
Different biofuels have their own conversion process to convert biomass into a finished/refined biofuel product
All biofuels generally go through a two step conversion process to produce the finished biofuel product:
This is the breaking down of the biomass material
Can involve high temperature deconstruction, and also low temperature deconstruction
Upgrading takes the broken down building blocks from deconstruction of the biomass material, and upgrades it into a finished biofuel product
energy.gov explains both of these conversion process steps in greater detail
Conversion of biomass to biofuel can be achieved thermally, chemically, and biochemically.
Different Types Of Biofuels, & Examples Of Biofuels
Two of the main types of biofuels are:
Renewable hydrocarbon ‘drop in’ fuels also exist
First Generation vs Second Generation vs Third Generation Biofuels
The difference between first, second and third generation biofuels, apart from when they were developed, is what they are each derived from.
Derived from food crops such as sugar and wheat (or plants such as sugarcane and corn starch)
Derived from non non edible biomass such as wood, organic waste, food crop waste, and other types of waste and residues.
Derived specifically from algae (and microalgae)
What Is Bioenergy? (Definition)
Bioenergy is energy derived from biomass
What Is Bioenergy Used For?
Bioenergy mainly used for:
– Heat generation
– Electricity generation
How Is Bioenergy Made?
There’s different ways that bioenergy can be made.
A few of the main ways might include:
– Direct combustion
Burning biomass like wood directly for heat
Biomass can also be burnt in a boiler to create steam, which turns turbine blades, which drives a generator, which produces electricity
– Conversion of biomass to biogas
Biomass is converted to renewable natural gas (biomethane), it can be purified and used to generate electricity
– Conversion of biomass to syngas
energy.gov outlines the steps in making syngas (a gas comprised mostly of carbon monoxide and hydrogen) via gasification
Once biomass is converted to syngas, syngas can be burned in a conventional boiler to produce electricity
Syngas can also ‘be used to replace natural gas in a combined-cycle gas turbine’
– Conversion of biomass to bio-oil
Once biomass is converted to crude bio-oil via pyrolysis, it ‘… is then substituted for fuel oil or diesel in furnaces, turbines, and engines for electricity production’
Different Types Of Bioenergy, & Examples Of Bioenergy
Bioenergy doesn’t really have different types
It would be accurate to say though that different biomass sources can be used as energy sources to produce heat or electricity directly
And also, different biomass sources can be converted into other forms of energy, like gases, to produce electricity
What Is Biogas? (Definition)
Biogas is gas derived from biomass, such as food waste, livestock waste, waste water, and crop residues, just as a few example
Biogas might mainly contain methane, and also some carbon dioxide (along with trace amounts of other gases)
What Is Biogas Used For?
eesi.org indicates that:
After biogas is captured, it can produce heat and electricity for use in engines, microturbines, and fuel cells.
Biogas can also be upgraded into biomethane, also called renewable natural gas or RNG, and injected into natural gas pipelines or used as a vehicle fuel.
eesi.org also outlines the uses for raw biogas, renewable natural gas/biomethane, and RNG converted to CNG or LNG in their report
How Is Biogas Made?
Biogas occurs in nature, landfills, and some livestock manure management systems
However, controlled and contained biogas is generated using an anaerobic digestor
Organic materials and organic waste undergo anaerobic digestion, which produces biogas, and also digestate (liquids and solids that can be used a soil amendment
Different Types Of Biogas, & Examples Of Biogas
Biogas can take the following forms:
– Raw biogas
– Renewable natural gas (RNG) (or biomethane)
A biogas that has been refined to remove carbon dioxide, water vapor, and other trace gases