Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called “biofuels,” to help meet transportation fuel needs. The two most common types of biofuels in use today are ethanol and biodiesel, both of which represent the first generation of biofuel technology.
What Is Biofuels?
Biofuel, any fuel that is derived from biomass—that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.
Biofuel is commonly advocated as a cost-effective and environmentally benign alternative to petroleum and other fossil fuels, particularly within the context of rising petroleum prices and increased concern over the contributions made by fossil fuels to global warming.
Many critics express concerns about the scope of the expansion of certain biofuels because of the economic and environmental costs associated with the refining process and the potential removal of vast areas of arable land from food production.
Need For Biofuels
Fossil fuels like coal and petroleum are the most common sources of energy. Fossil fuels are non-renewable sources, which means one day we will run out of them. As a result, the price of petroleum is also increasing day-by-day.
Fossil fuels take millions of years to form through various geological processes. Their process of extraction is also very expensive. The emission of greenhouse gases (GHGs) by fossil fuels leads to the global warming.
So, there is great demand for some renewable source of energy which should be cost effective and environmental friendly in nature. A biofuel is a great alternative for fossil fuels.
How are advanced biofuels produced?
Biofuels are obtained by transforming biomass, an organic material that comes from plants and animals. This is done using mechanical, thermochemical, and biological processes, and depending on the origins of the raw material used to make the biofuels and the processes used, they can be classified as follows:
#1. First-generation biofuels.
consists of fuels obtained from food crops. First-generation biofuels are a transition fuel, a bridge to advanced biofuels. Their use will be progressively limited, but in the meantime they meet the sustainability and carbon footprint reduction criteria established by the European Renewable Energy Directive and their entire value chain is certified. Examples of these biofuels are those created from vegetable oils, such as bioethanol and biodiesel.
#2. Second-generation or advanced biofuels.
are those that come from organic wastes that are not destined for or compete with food, from the agri-food and forestry industries, used cooking oils and the organic matter from urban wastes.
The use of these wastes favors the reuse of resources and reduces the arrival of waste at landfills. These include renewable diesel (HVO), sustainable aviation fuel (SAF), biogas, and biomethane.
#3. Third-generation biofuels.
these fuels are extracted from algae and aquatic plants with a natural oil content of at least 50 %. The production of this biofuel has not yet been carried out on a commercial scale.
#4. Fourth-generation biofuels.
the fourth generation goes a step further and seeks to genetically modify microorganisms to improve the efficiency of CO₂ capture and storage. These biofuels are also not commercialized at the moment, although there are pilot plants in Brazil and the United States.
Types of Biofuels
Advanced biofuels can be found in different states: solid, liquid, or gaseous. These are currently the most commonly used biofuels:
#1. Ethanol.
Ethanol is essentially ethyl alcohol or pure alcohol, and it’s the most common alternative biofuel used in cars today. While ethanol can be made from different sources, the most common are sugarcane and corn.
The ethanol making process involves the fermentation of high carbon content matter, mainly cellulose and sugars extracted from sugarcane or corn. Naturally, ethanol is clean, releasing roughly 15% less greenhouse gas emissions. It’s usually incorporated with other fuels to reduce carbon emissions.
In large-scale sugarcane producing countries such as Brazil, most motor-vehicles are powered by 100% ethanol. In 2011, the US government approved the use of ethanol blends of up to 15% in car models newer than 2001.
But, people have used ethanol blends of 10% for years with no need for modifications. Unfortunately, there are controversies surrounding the sustainability of ethanol.
#2. Biodiesel.
Biodiesel is a liquid biofuel that’s derived from a combination of vegetables and fats, and oils from both animals and plants. Some manufacturers simply collect used restaurant oil to make biodiesel. To obtain pure biodiesel, manufacturers focus on plants with high energy content.
Alcohol is also a key ingredient in the manufacture of biodiesel. Biodiesel is quickly gaining popularity as finding recycled cooking grease, vegetable oils, and animal fat is quite easy.
Compared to petroleum-based diesel, biodiesel minimizes tailpipe emissions, and it burns cleaner. It also doesn’t contain sulfur, which eliminates sulfur dioxide emissions.
In most countries, biodiesel production infrastructure isn’t on a mass-scale, making it commercially expensive to produce.
#3. Biobutanol.
Although biobutanol isn’t as popular as biodiesel and ethanol, it’s the only biofuel with the most potential. Biobutanol is much like biodiesel, but it’s derived from algae or bacteria instead of plant or animal fats.
Biobutanol has a higher energy per unit content than methanol and ethanol, and it has the potential to be used directly in standard gasoline engines with no modifications. Since biobutanol is difficult to produce, it’s less well known, making production costs relatively high.
Luckily, it offers users numerous benefits such as:
- It’s non-corrosive to pipelines and engines
- Its high octane level ensures there’s zero or little loss in fuel mileage
- It can use existing supply and pipeline chain infrastructure for distribution
#4. Biogas.
Biogas is a type of renewable gas formed by the anaerobic decomposition of organic matter, such as agricultural waste, manure, food waste, and sewage.
This natural process releases methane and carbon dioxide, with methane being the main component of biogas. Its use contributes to closing the organic waste cycle and reducing dependence on fossil fuels.
#5. Biomethane.
A sustainable alternative to natural gas, it is known as the renewable gas whose origin comes from biogas. Unlike biogas, biomethane is purer, so it can be mixed with convectional gas and used to generate electricity and heat, as well as to power vehicles.
#6. Renewable diesel (HVO).
This biofuel, which usually comes from used cooking oil, can be used as a complement to traditional fuel. In fact, some cars and trucks already use this renewable fuel. The benefits of this hydrotreated vegetable oil are that it is more efficient and sustainable by transforming organic waste into fuel, and greenhouse gas emissions are lower than those of traditional fuel.
Advantages Of Biofuel:
- Promotes a healthier population.
- It helps in maintaining a cleaner environment.
- There is no emission of hazardous gases, such as Carbon monoxide (CO) and sulphur oxide (SO).
- Using biofuels rather than fossil fuels, there is the only emission of non-toxic materials, which reduces the risk of cancer and breathing problems in human beings.
- Biofuels are friendly to the environment because they reduce the risk of global warming.
Disadvantages Of Biofuel:
- It disturbs the life cycle.
- Cost of labour and it requires huge space for storage.
- More water consumption, especially in dry climates.
- Growing biomass for biofuel production increases the demand for agricultural land.