Everything you need to know about bioenergy or biomass energy


In a previous article I was talking about geothermal energy and I commented that the renewable energies that exist in this world, there are some better known and used, such as solar and wind energy, and others less known (sometimes almost not named) such as geothermal energy and that of biomass.

The energy of biomass or also called bioenergy it is less known and used than other types of renewable energies. In this post we are going to know everything related to this type of renewable energy and its possible uses.

What is biomass energy or bioenergy?

Biomass energy is a type of renewable energy that is obtained through the combustion of organic compounds obtained through natural processes. They are organic remains such as pruning remains, olive stones, nut shells, wood remains, etc. That come from nature. You could say that they are the waste of nature.

biomass waste

These organic remains are burned by direct combustion or can be transformed into other fuels like alcohol, methanol or oil, and that way we get energy. With organic waste we can also obtain biogas.

Different sources of obtaining bioenergy

The main characteristic of bioenergy is that it is a type of renewable energy and, therefore, sustainable for society and its energy consumption. As I have mentioned before, this energy is obtained through the combustion of different types of waste, whether forest or agricultural, that otherwise would not be used at all. However, we are going to see what types of biomass sources are used for the generation of bioenergy and what they are used for:

  • Bioenergy can be obtained through energy crops that are exclusively intended for it. These are some plant species that until now had hardly any nutritional function or for human life, but which are good producers of biomass. That is why we use this type of plant species for the production of bioenergy.
  • Bioenergy can also be obtained through different forest exploitation activities, when forest residues cannot be used or sold for other functions. Cleaning these forest residues has the advantage that, in addition to contributing to the cleaning of the areas and the production of sustainable energy, it avoids possible fires due to the burning of the remains.

agricultural residues for biomass

  • Another source of waste for the production of bioenergy can be the use of lindustrial process residues. These can come from carpentry or factories that use wood as raw materials. It can also come from disposable waste such as olive pits or almond shells.

How is biomass energy generated?

The energy obtained through organic remains is produced through their combustion. This combustion takes place in boilers where the material burns little by little. This procedure generates ashes that can be used later and used as compost. An accumulator can also be installed to be able to store the excess heat generated and to be able to use that energy later.

Biomass boilers

Biomass boilers

Main products derived from biomass

With organic waste, fuels such as:

  • Biofuels: These are obtained from both animal and plant organic remains. The nature of these remains are renewable, that is, they are constantly produced in the environment and are not depleted. The use of biofuels makes it possible to replace fossil fuels obtained from oil. To obtain biofuel, species for agricultural use, such as corn and cassava, or oleaginous plants such as soybeans, sunflowers or palms can be used. Forest species such as eucalyptus and pines can also be used. The environmental advantage of using biofuels is that it constitutes a closed carbon cycle. That is, the carbon that is emitted during the combustion of the biofuel has already been previously absorbed by the plants during their growth and production. Although this is currently under discussion since the balance of absorbed and emitted CO2 are unbalanced.


  • Biodiesel: This is an alternative liquid biofuel that is produced from renewable and domestic resources such as vegetable oil or animal fats. It does not contain petroleum, it is biodegradable and it is not toxic because it is free of sulfur and carcinogenic compounds.
  • Bioethanol: This fuel is produced as a result of the fermentation and distillation of the starch contained in the biomass, which is previously extracted by enzymatic processes. It is obtained through the following raw materials: starches and cereals (wheat, corn, rye, cassava, potatoes, rice) and sugars (cane molasses, beet molasses, sugar syrup, fructose, whey).
  • Biogas: This gas is the product of the anaerobic decomposition of organic matter. In buried landfills, biogas is extracted through a pipe circuit for later energy use.

What is biomass used for and what is its consumption in our territory?

Generally and more or less similar to geothermal energy, biomass it is used to generate heat. At an industrial level we can find a use of said heat for the generation of electrical energy, although it is more complex and expensive. In order to take advantage of the heat generated by the combustion of organic waste, biomass boilers are installed in homes to have heating and also to heat water.

In our territory, Spain is in the fourth place in the countries that consumes the highest amount of biomass. Spain is the European leader in the production of bioethanol. Statistics show that biomass in Spain reaches almost 45% of the production of renewable energies. Andalusia, Galicia and Castilla y León are the autonomous communities with the highest consumption due to the presence of companies that consume biomass. The evolution of biomass consumption is generating new technological options and is increasingly being developed for its use in the production of electrical energy.

Biomass boilers and their operation

Biomass boilers are used as a biomass energy source and for heat generation in homes and buildings. They use natural fuels as a source of energy such as wood pellets, olive pits, forest residues, nut shells, etc. They are also used to heat water in homes and buildings.

The operation is similar to that of any other boiler. These boilers burn the fuel and generate a horizontal flame that enters a water circuit in the heat exchanger, thereby obtaining hot water for the system. To optimize the use of the boiler and organic resources such as fuels, an accumulator can be installed that stores the heat produced in a similar way to how solar panels do.

Biomass boilers

Biomass boilers for buildings. Source: http://www.solarsostenible.org/tag/calderas-biomasa/

In order to store the organic waste that will be used as fuel, the boilers need to a container for storage. From that container, by means of an endless screw or suction feeder, it takes it to the boiler, where the combustion takes place. This combustion generates ashes that must be emptied several times a year and accumulate in an ashtray.

Types of biomass boilers

When choosing what type of biomass boilers we are going to buy and use, we have to analyze the storage system and the transport and handling system. Some boilers allow burning more than one type of fuel, while others (such as pellet boilers) only allow one type of fuel to burn.

Boilers that allow burning more than one fuel need increased storage capacity since they are larger and more powerful. These are normally intended for industrial uses.

On the other hand we find himas pellet boilers which are the most common for medium powers and are used for heating and domestic hot water using accumulators in homes of up to 500 m2.

Advantages of using biomass energy

Among the advantages that we find in the use of biomass as energy we have:

  • It is a renewable energy. We are talking about the use of waste generated by nature to generate energy. That is why we have an inexhaustible source of energy, since nature generates these types of waste continuously.
  • Reduces greenhouse gas emissions. As we have mentioned before, the emissions we produce during their combustion have been previously absorbed by the crops during their growth and production. This is controversial today, since the balance of CO2 emitted and absorbed is not balanced.
Biomass power plant

Biomass treatment plant. Source: http://www.fundacionsustrai.org/incineracion-biomasa

  • The market price is low. This use of energy contained in biomass is very economical when compared to fossil fuels. It usually costs a third less.
  • Biomass is an abundant resource around the world. In almost all places on the planet, waste from nature is generated and can be used for its use. In addition, in general, large infrastructures are not necessary to bring the waste to its point of combustion.

Disadvantages of using biomass energy

The disadvantages of using this energy are few, but they do have to be taken into account:

  • In some areas, due to more difficult biomass extraction conditions, can be expensive. This also usually occurs in utilization projects that involve the collection, processing and storage of some types of biomass.
  • Large areas are needed for processes used to obtain biomass energy, especially for storage, since the residues tend to have low density.
  • Sometimes the use of this energy can cause damage to ecosystems or fragmentation due to biomass collection activities and the alteration of natural spaces to obtain resources.

With these ideas you can have a broader vision of this type of renewable energy. However, on another occasion I will tell you more about the types of biomass boilers, their operation, types and advantages, and about the aforementioned controversy about emissions into the atmosphere.

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