Biofuels are a class of renewable fuels derived from organic material known as biomass. These organic materials for biofuels include agricultural waste, corn, algae, and trees. Biomass is turned into fuel which then produces bioenergy.
This sort of energy uses what has been stored in biomass through natural processes like photosynthesis in plants. The chemical energy produced through such processes can be conserved and utilized for human energy purposes.
Currently, about 10% of the world’s energy needs are met from these sources. This number is likely to grow as countries continue to invest in and adopt green energy policies.
Biofuels include two types: primary or secondary.
We already utilize several other types of alternative energy such as wind, solar, and hydroelectric. However, these resources can’t replace the feedstocks we need for products like jet fuel, gas, and petroleum diesel fuel.
This is where biofuels come into the equation. They serve as another type of alternative energy source to create fuels that other renewables cannot.
Wood is the most direct and simple organic material used to create fuel. It is both a biomass and a biofuel used in the production of other alternative fuels. It can be burned in many forms:
This makes wood a common and highly adopted type of fuel throughout the world.
Wood serves as an essential component in broader-scale energy use as well. Pulp and paper, forestry, and other wood processing industries are often left with by-products and waste. Otherwise known as woody biomass, these leftovers can then be used in secondary renewable fuel production.
Ethanol is a liquid biofuel produced by fermenting plant and animal biomass. It is an alcohol derived from high-carbon elements of feedstocks, such as cellulose and sugar. It is often made from a combination of plant and animal biomass.
Common sources of ethanol biofuels include fibrous, sweeter plants such as corn, sorghum, beets, and sugarcane. These materials are broken down and combined with yeast to ferment. Denaturants are also added to stop human consumption.
Ethanol is mostly clean in terms of production and combustion, making it an attractive option for reducing carbon emissions. Global biofuel mandates require many countries to move toward higher adoption. For transportation needs like jet fuel, ethanol can help countries reach compliance levels.
Biodiesel is a liquid biofuel produced mainly from vegetable oils and animal fats to replace petroleum diesel fuel. Oils are combined with alcohol and processed into renewable diesel fuel. These higher energy sources allow for improved energy output within transportation.
Biodiesel offers several advantages. It can be made from oils that would otherwise become waste such as used cooking oil and yellow grease. Animal byproducts from meat processing can also be salvaged for a stable, renewable diesel production pathway.
The conversion process from feedstocks into fuels also produces a coproduct: glycerin. Glycerin made from this source reduces the need for production elsewhere. This conserves even more resources and improves biodiesel’s carbon footprint.
Methanol is another liquid fuel used in specialized areas such as auto racing. It is a type of alcohol fuel like ethanol. Methanol was mostly used as an early alternative fuel in the 1990s. Its higher resource demand and production costs make it mostly obsolete today.
Butanol, another alcohol fuel, contains more energy per ounce than either ethanol or methanol. It is also closer in chemical structure to gasoline than other alternative energy. As a liquid biofuel, butanol is derived from many of the same ingredients as ethanol. However, it has higher production costs leading many producers to make ethanol instead. Ongoing research and development may position butanol as a top choice among alternative fuels in the future.
Biogas serves as an alternative to natural gas and is produced by breaking down methane. As methane emissions significantly contribute to climate change, converting it into biogas can lower greenhouse gases, converting them into a critical fuel source.
About 40% of methane emissions come from the world’s cow population. Agriculture already uses biogas to conserve methane. It is also gaining popularity in consumer-level applications, such as gas cylinders.
Alternative biofuels are produced using a wide range of feedstocks derived from organic, renewable sources. Examples of feedstocks for biofuels include:
Other sources include woody biomass, various non-food crops (or waste from food crops like sugar cane), organic waste, and manure.
Unlike fossil fuels, renewable feedstocks can be continually produced. This makes them a sustainable alternative to an otherwise limited stock of fuel sources.
Ongoing work in this field will help find potential new feedstocks for liquid biofuel production. As we improve technology and efficiency, we will likely see even more available options.
Yes, these fuels are considered renewable energy sources. They are derived from organic matter, such as plants or animal waste. The required organic matter can be grown and replenished over time, making them a renewable resource.
In some cases, feedstocks come from material that would otherwise be thrown away. One example is used cooking oil (UCO). Restaurants must frequently dispose of this oil. Using UCOs as a feedstock stops them from going straight to a landfill. It conserves a large amount of energy that would have become waste.
The cost of these fuels varies depending on several factors, including:
Initially, the development and infrastructure costs led to higher prices of biofuel produced. However, as clean energy investments continue to increase, production costs are expected to decrease. Eventually, bioenergy will become more economically competitive with traditional fuels.
Emerging technology is also being developed to help solve issues with contaminated recyclable materials. Take packaging or materials using both paper and plastic, for example. The plastic would contaminate the paper and prevent it from getting recycled. But developing techniques could find a way to convert these items into some form of fuel. This sort of innovation will continue to solve many of the waste and carbon emission challenges the world currently faces.