The generation of biofuels, a priori, represents several advantages over obtaining fossil fuels used to obtain fossil energy. The main advantage is that the regeneration of resources is not millions of years as it happens with coal, oil or natural gas. In any case, the regeneration of biofuels is not fast enough to be considered a renewable energy source either. They are therefore considered a non-renewable energy source.
On the other hand, biofuels continue to be an indirect way of harnessing solar energy. In this case, solar energy is used thanks to the photosynthesis of cultivated plants. The rest of the energy from this fuel comes from the chemical energy that the plant generates by processing the nutrients in the soil.
With the aim of improving biofuel production and mitigating inconveniences and the negative effects of its production, its evolution can be divided into 4 different generations:
What are first generation biofuels?
First generation or conventional biofuels are biofuels made from food crops grown on farmland.
With this generation of biofuel production, food crops are explicitly grown for fuel production, and nothing else. The sugar, starch, or vegetable oil obtained from the crops is converted to biodiesel or ethanol, using transesterification or yeast fermentation.
What are second generation biofuels?
Second-generation biofuels are fuels made from various types of biomass.
Biomass is a broad term meaning any source of organic carbon that is rapidly renewed as part of the carbon cycle. Biomass is derived from plant materials, but can also include animal materials.
While first-generation biofuels are made from sugars and vegetable oils found in arable crops, second-generation biofuels are made from lignocellulosic biomass or woody crops, agricultural residues, or waste plant material (from crops intended for food but already have fulfilled their food purpose).
The raw material used to generate second generation biofuels should grow on land that cannot be used to grow food effectively and its cultivation should not consume much water or fertilizers.
This form of fuel generation has advantages and disadvantages. The advantage is that, unlike regular food crops, no arable land is used solely for fuel production. The downside is that, unlike regular food crops, it can be quite difficult to extract the fuel. For example, a series of physical and chemical treatments might be required to convert lignocellulosic biomass to liquid fuels suitable for transport.
What are third generation biofuels?
Third generation biofuels are based on the philosophy of harnessing aquatic plants.
A self-published article by Michael Briggs of the UNH Biofuels Group provides estimates for the realistic replacement of all vehicular fuel with biofuels by using algae that have a natural oil content greater than 50%, which Briggs suggests is You can grow in algae ponds in sewage treatment plants.
These algae can then be removed from the system and transformed into biofuels. Subsequently, the dry residue is reprocessed to create ethanol.
Algae production to harvest oil for biofuels has not yet been carried out on a commercial scale, but feasibility studies have been carried out to arrive at the above yield estimate. In addition to its projected high yield, the use of algae does not imply a decrease in food production, since it does not require farmland or fresh water.
Fourth generation biofuels
Similarly, fourth generation biofuels are manufactured using non-arable land. However, unlike third generation biofuels, they do not require the destruction of biomass.