Biomass: questions and answers

19 July, 2022

The concept of biomass is so broad that, although it is a widespread energy source, it still raises questions. These are some of the most common:

What is biomass?

Biomass is all organic matter that is used as an energy source. There is a wide range of organic materials used as feedstock in the different processes of energy production from biomass, which gives rise to different ways of classifying them.

What types of biomass are there?

In terms of energy, three types of biomass are generally considered:

  • Natural, which is produced by nature itself, without human intervention, e.g., dry branches or leaves.
  • Residual, obtained as a by-product of a process, e.g., olive stones or nut shells.
  • Energy crops, e.g., fast-growing crops for biofuel production, e.g., maize.

What is biomass for?

Biomass can be converted into energy in different ways and, depending on each of them, it can be used to produce electricity, heat or biofuels.

Is it sustainable energy?

Taking into account that renewable energies are obtained from inexhaustible and natural sources, we can state that biomass is a renewable energy.

However, it is important to note that as a very heterogeneous energy source (with a large number of possible raw materials and different processes to transform them into energy), there is biomass that is not regenerated by natural means. This is the case for energy crops, which can be unsustainable if used unrestrictedly and on a massive scale, putting excessive pressure on agricultural soils and forests.

In general terms, energy obtained from biomass is sustainable (renewable and emission-neutral), but the entire transformation process must be analysed in order to make this statement in each specific case.

Biomass energy is sustainable, but the whole transformation process must be analysed to make this statement in each specific case

What raw materials are used?

There are five most commonly used feedstocks for biomass energy production:

  • Woody products (waste from the timber industry, firewood, etc.).
  • Agricultural products (agricultural waste, energy crops, etc.).
  • Food products (food industry waste, whey, etc.).
  • Livestock products (animal waste, manure, etc.).
  • Human waste (landfill waste, sewage, etc.).

How are they processed?

Biomass is a very versatile energy, as it can be used for different purposes and obtained from different materials. Accordingly, there are various forms of transformation. The main ones are:

  • Combustion, which releases energy (in the form of steam – heat – or electricity) from the burning of biomass.
  • Anaerobic digestion, which breaks down matter by the action of microorganisms in the absence of oxygen, generating biogas that can be used for energy.
  • Gasification, which transforms biomass into fuel gas at high temperatures.
  • Pyrolysis, a thermochemical degradation process in the absence of oxygen, which chemically decomposes materials by applying heat.


What are the benefits of biomass?

The most relevant benefits of biomass as an energy source are:

1. It is low polluting. Where emissions are released, they are minimal and highly controlled through regulations at European and national level, which help improve air quality, combat climate change, etc.

2. It is an abundant source of energy, as it allows the use of different types of matter. This makes it potentially a renewable energy that is available anywhere in the world.

3. It reduces dependence on traditional fuels by having a lower cost. This, in turn, brings other advantages related to environmental protection or the reduction of economic dependence on other countries.

4. Rural development. Some types of biomass are found, to a greater extent, in rural areas. This, together with the energy transition, turns them into high interest areas. The result is the creation of new jobs, the maintenance of the population and the development of related economic activities.


Is it a viable energy source?

Definitely, yes. Compared to traditional fossil fuels, it is all advantages: significantly lower cost, less polluting, potentially unlimited energy and with a good number of associated benefits (rural development, forest clean-up, circular economy, waste reduction, independence from other countries, production of natural fertilisers, etc.).

In addition, rapidly advancing technological developments are helping to maximise the benefits and reduce the disadvantages of this energy. The increased use of biomass, coupled with other renewable energies, offers hope for a guaranteed, economic and sustainable energy supply for the entire world.

The increased use of biomass offers hope for a secure, economic and sustainable energy supply for the entire world

What is the future of biomass?

Biomass will be key to reducing greenhouse emissions and waste. According to The International Renewable Energy Agency (IRENA), biomass can provide 20% of the world’s total energy supply; 60% of renewable consumption. But for the future to be truly sustainable, restrictions on the biomass sector need to be introduced to ensure that it is a clean, renewable energy source, which does not clear arable and forestry land for energy crops. Sustainable sourcing of raw materials is and will be crucial.