energy crops

All about energy crops

Generating energy through agriculture

Agriculture represents an excellent source of raw materials for the generation of bioenergy, which is renewable and ecological. We tell you what energy crops are, what benefits they provide, and their main applications.

Reducing our dependence on fossil fuels is one of the big challenges of the ecological transition. Energy crops constitute an alternative with an enormous potential to achieve this goal, as well as having other advantages on an economic and environmental level. Thanks to them, it is possible to produce biofuels such as biodiesel, bioethanol, and biogas to achieve bioenergy, a type of renewable energy on the rise in recent years.

 

What are energy crops?

Energy crops are a very broad category, which covers all those plant species whose main production is destined to the production of biomass to generate thermal or electrical energy or produce biofuels.

Biomass is one of the renewable energies that has experienced the greatest growth over the last few years, with an enormous potential to transform our energy model into a long-term efficient and sustainable system.

Biomass and energy crops, also called agroenergy crops and bioenergy crops, are relatively modern concepts, but in reality biomass, specifically firewood, was the first source of energy used by humans to light fires for heating or cooking.

In Spain, sustainability and greenhouse gas emissions reduction criteria for biofuels, bioliquids (liquid fuels intended for energy uses other than transportation), and biomass fuels are regulated by Royal Decree 376/2022, of May 17th. According to this regulation, at least 28% of the energy used in the transportation sector by 2030 must come from renewable sources.

Benefits of energy crops and sustainable agriculture

  1. Energy crops are a very abundant raw material and with a much more affordable cost than oil or coal.
  2. Sustainable agriculture and energy crops represent a boost for the agricultural sector that, as well as being cost-effective and offering high productivity, also contributes to preserving the soil and preventing its erosion.
  3. Bioenergy obtained from these kinds of crops is renewable, efficient, and sustainable in the long term, so it represents one of the most promising alternatives to fossil fuels.
  4. By reducing global dependence on fossil fuels, energy crops also contribute to reducing greenhouse gas emissions and advancing towards decarbonization.
  5. Biofuels generated from energy crops are crucial to transform the transportation sector, one of the largest contributors to carbon emissions.
  6.  Energy crops promote the circular economy, as they favor the reuse of natural resources through an environmentally-friendly process.
  7.  In the economic sphere, energy crops represent a great opportunity for the creation of new businesses and jobs, especially valuable for rural areas.

Examples of energy crops

woody energy crop of sunflowers

In general, plants are classified into woody and arable crops.

  • Woody crops are the oldest energy crops, used to generate heat or energy, transforming them into wood logs, wood chips, pellets, or sawdust. 
  • For its part, arable crops are characterized by storing approximately twice as much carbon dioxide as woody crops, an ideal quality for bioenergy generation.

Alongside woody crops, rapeseed, sunflower, corn, and sugar cane are some examples of energy crops that are very widespread today, but as we explain below, there are many more species suitable for biofuel production.

  • Energy crops to generate biomass

Biomass represents a solution with multiple benefits for the production of bioenergy and biofuels, both on an economic and environmental level. Among energy crops for biomass, fast-growing woody crops, such as willow or poplar, which are harvested in short cycles of three to five years, prevail. Spain, with its Mediterranean climate and its extensive agricultural production, offers an optimum environment for these energy crops.

The biomass resulting from these crops can be used to produce biofuels such as biodiesel or bioethanol or to generate thermal energy or electricity, suitable both for small installations, such as a household gas boiler, and for use in industrial boilers.

  • Energy crops to produce biodiesel

This fuel is mainly obtained from vegetable oils or animal fats. Which energy crops are used to make biodiesel? For this fuel, species with a high oil content are used, such as rapeseed, sunflower, soybean, palm, or castor oil, to name a few. Algae and other plants of marine origin are also suitable energy crops to produce this biofuel.

Currently, biodiesel is used above all in the automotive sector, as an alternative to diesel of mineral origin. There are also specific boilers for biodiesel, suitable for domestic heating.

  • Energy crops to produce bioethanol

For the production of bioethanol, the most suitable energy crops are species rich in sugars, such as sugar cane, sugar beet, corn, sweet sorghum, oats, barley, and rye. Once collected, the sugar present in these crops ferments and is converted into bioethanol, which can be used as a fuel for vehicles, in a similar way to gasoline or diesel, for power generation, or for the heating of homes, where fireplaces and heaters powered by this biofuel are increasingly frequent.

  • Energy crops to produce biogas

Biogas is a biofuel generated from the decomposition of organic matter anaerobically, i.e. in the absence of oxygen. This process decomposes biodegradable organic matter - forestry waste, derivatives of the agro-food industry, urban organic waste, etc. - to obtain biogas. Among the energy crops, corn, millet, and white sweet clover are some of the species most used today for the generation of this biofuel, ideal for achieving sustainable transportation or generating thermal or electrical energy.