Biofuels: Sustainable and Climate Friendly Energy Solution

Biofuels are the need of the hour and will help pave the way for a low carbon future

 Since the past few centuries, conventional energy resources such as fossil fuels have remained an integral part of daily human needs. According to IRENA data (2019-20),84% of primary energy was from oil, coal and gas across the globe. Conventional fuels (coal, crude oil, natural gas) when burned, intensify the amount of greenhouse gases, causing global warming to worsen. In addition, the emission of Nitrogen Oxides from these fuels into the atmosphere results in smog, and acid rain, which of course worsens the scenario at a given place, if not globally. It has been documented that air pollution leads to premature deaths worldwide on account of infection due to particulate matter in the air, causing cancer and various respiratory diseases. Burning of oil, coal and gas not only results in increased global emissions of the GHGs but also alters basic chemistry of oceans, making them more acidic, which in turn hinders the growth of phytoplankton responsible for photosynthesis and production of 50-80% of earth’s oxygen! To make matters worse, there are cases of oil spills and leakage during oil extraction and its transport, leading to the pollution of drinking water sources risking entire freshwater and ocean ecosystems. Moreover, the energy crisis has begun to hit worldwide owing to the rapid industrialization and population growth. Given the universal knowledge and realization that fossil fuels are non-renewable, concerns on global warming and the mounting price of petroleum-dependent fuels have been on the rise lately, which has resulted in the search for viable alternatives, making it an area of interest and research for concerned stakeholders. 

A number of alternative fuels (biofuels) that can harvest bioenergy from biomass are potentially available and are being used or are under investigation at certain stages of development. Also, emission of harmful pollutants from biofuels is negligible when compared with the conventional fuels, hence they can be blended with existing fuels to find an effective way of reducing CO2  emissions. Biofuels are defined as any hydrocarbon fuel produced from an organic matter (either living or once living) in a short span of time. They can be solid (wood chips, manure), liquid (bioethanol, biodiesel) or gas (biogas). The use of biofuels and its global production has seen a dramatic increase in recent years, from about 108.2 billion litres in 2018 to about 161 billion litres in 2019.

Four Generations of Biofuels

Biofuels can be categorized into four different generations on the basis of feedstock type and the conversion process used. 

Biofuels produced directly from food or animal feedstock are referred to as first-generation (1st gen) biofuels. Crops such as sugarcane, starch, corn, molasses, sugarbeet, wheat etc, are the most widely used ones for bioethanol production while palm oil, rapeseed oil, soybean oil, sunflower oil have been proved to be effective crops for biodiesel production. However, since first generation biofuels are directly being derived from food components, the utilization of such raw materials witnessed significant criticism as the biomass was competing against the  food supply. Despite the criticism, bioethanol production from first generation technologies is estimated to increase to more than 100 billion litres in 2022.

Although development and usage of first generation biofuels is practiced fairly well across the world, they come with certain restrictions owing to the energy consumption, utilization of arable lands and also the never ending debate on fuel vs food. The increase in the price of feedstock is leading to a growing interest towards second generation biofuels. A key characteristic of second generation biofuels is that they are predominantly derived from non-food feedstock. These cheaper lignocellulosic biomass can be harvested from dedicated energy crops (such as miscanthus, switchgrass), forest residues, agriculture residues, banana waste and from other different herbaceous and woody energy crops, thus eliminating the main problem from first generation biofuels. The second generation biofuels also aimed at being more cost-effective in comparison to existing fossil fuels. Clearly, conventional carbohydrates can not compete significantly on the world’s demand for petroleum based fuels. Lignocellulose could meet that demand both from waste and from purposefully grown energy crops. The biomass of  crop plants can not only be used in the production of bioethanol, but  it also offers great possibilities to enhance the income levels of smallholder farmers. However, utilization and conversion of lignocellulosic resources has been  a challenging task in the production of cost-effective, sustainable biofuel energy sources. 

The third generation biofuels took advantage of energy crops such as algal biomass. These algal biomasses add more value to biofuels production due to their low cost, easy growth, high lipid content and are high energy renewable feedstock. In addition, algae based biofuels can be manufactured into a wide variety of fuels such as diesel, petrol and for pilot plant fuels. They are also potentially carbon neutral i.e. the amount of carbon emitted and absorbed is equal. Algal species such as Chaetoceros calitrans, chlorella sp., and some others have been identified as potential sources for biofuel production. However, for now,  microalgal biomass is not a favorable potential choice for industrial biofuel production because of the extensive energy input compared to current terrestrial energy crops and also due to high lipid variation in microalgal species.

The fourth generation biofuel technology utilizes the biomass materials which have absorbed CO2 while growing and are subsequently converted into biofuels. The main purpose of fourth generation biofuels is production of sustainable energy along with CO2 sequestering. Carbon capturing makes these biofuels processing technology carbon negative than simply carbon neutral, by creating artificial carbon sinks as it locks more carbon than it produces.

Way forward

Transportation fuel that is derived from a biological source or biofuels is a potential renewable alternative to conventional fuels (fossil fuels). It is sustainable, reduces India’s dependence on imported oil and generates lower greenhouse gas emissions when compared to fossil fuels. However, it’s dependence on India’s energy inventory will be greatly affected by laws and policies, including agricultural practices and subsidies.  The Petroleum Secretary of India has said that from April 1, 2023, 20 percent ethanol will be blended in petrol.

The current scenario calls for an acceleration in biofuels production from renewable resources and a curb on the status quo use of fossil fuels. Additionally, further attention must be paid to the engineering of industrial strains and also on the treatment processes since the biggest challenge yet prevailing in the biofuel industry is how to make the production of biofuels easy and cost-effective.