The imminent depletion of petroleum reserves and the rise of global warming and climate change debates have brought topics like biofuel, renewable energy, solar power and many more to the forefront of social and scientific discussions. There are many sources of alternative energy that are being developed to replace or reduce the use of fossil fuels in various ways. Biofuels are coming up as a popular alternative to fossil fuels especially in vehicles and heavy machinery. Biofuels are also used for heating homes and cooking food.
Biofuels are fuels generated from biological material that is still living or recently lifeless. Energy can be harnessed from the fresh organic matter and channelled to power machinery or for generation of heat that can be used to run engines, warm homes, cook food, or to generate electricity. Biofuels can exist in liquid, gas or solid form.
Types of Biofuel
Biofuels in solid form are referred to as biomass and consist of plant and animal waste that is used in its solid state such as wood and dry cow manure as well as farm waste. Biomass is burned directly to generate heat in furnaces, ovens and steam engines. In sugar factories, for example, the solid waste (bagasse) collected after the molasses has been extracted from sugar cane is dried then burned in special cogeneration power plants to generate electricity.
The basic term given to gaseous biofuel is Biogas. Biogas is generated from the decomposition of biological material. When organic waste is collected together, it begins to decompose and ferment. If it is placed in an oxygen-rich environment, it will generate carbon dioxide but if deprived of oxygen, the waste will generate methane gas, which is highly flammable.
The methane gas is what is referred to as biogas. Scientists and engineers have developed several systems known as biodigesters designed to harness the generation of biogas from plant, animal and human waste for use in cooking, heating homes and specially modified buses, trucks and cars.
The most popular biofuel in use today is Ethanol. It has been blended in with gasoline in Brazil and some parts of the USA to reduce fossil fuel consumption and vehicle carbon emissions. This liquid biofuel is made by using yeast to ferment grains and plants with high sugar or starch content like sugar cane, beets and corn. It can also be produced through advanced technological processes like gasification where organic matter is heated to high temperatures in a low-oxygen environment to produce biogas which is then converted to ethanol. Scientists have recently developed ways to synthesize ethanol from waste cellulose found in inedible plants like switchgrass and scrap wood as well as some food by-products.
The second type of liquid biofuel is known as Biodiesel and is produced from plants that have high vegetable oil content. The oils in these plants are extracted through various ways and then heated to reduce their viscosity so that they can be burned directly to run diesel engines and heavy machinery. The most common sources of Biodiesel are palm oil, castor oil seeds and soybeans.
One of the most significant discoveries in the biofuel industry was that algae could be cultured and harnessed to generate biofuel. This immense source of biofuel is widely accepted because it is cultured from water that is not suitable for farming or drinking and generates the oil from inedible plant materials.
Algae are a form of bacteria that grow in wastewater and can be used to produce a fuel called Biobutanol. Biobutanol is a very competitive alternative to petrol and can be used directly in ordinary cars without modifying the engines. This fuel has very high octane levels and has great fuel efficiency.
Controversy of Biofuel
Although Biofuels have several advantages over the use of fossil fuels to generate energy, there are various debates against their commercial development. While a number of these debates are based on personal opinions and preferences, there are a few quite valid arguments against the production and use of biofuels.
- Food Vs Fuel: Large debates have risen against using food crops like corn and soybean to produce biofuels rather than to feed the hungry. To solve this some developers have opted to use inedible or non-food plants to produce biofuels such as cellulosic ethanol.
- Land use: in relation to the previous point, arguments have risen against using arable land and other resources to grow crops for fuel rather than food.
Like any disruptive technology, biofuels have many challenges to overcome, but scientists are hard at work finding solutions such as the use of Algae which grows in wastewater and the use of wastelands that are not suitable for farming to grow energy crops. In time they will be globally accepted and sought after.