Have you ever switched on a light? Have you ever used a laptop or a smartphone? Have you ever ridden in a car or a bus? If you answered “yes” to any of these questions, you have used energy. As technology develops and the world’s population grows, people need more and more energy. But meeting this need can be a challenge!
Since the Industrial Revolution, most energy for human activities has come from burning fossil fuels. People use fossil fuels to produce electricity, to run motor vehicles and to power factories. In 2013, fossil fuels supplied just over 80 percent of the world's energy.
But this won’t always be the case. Burning fossil fuels releases greenhouse gasses, which world leaders interested in fighting climate change are trying to reduce. And one day, fossil fuels will simply run out. That’s why scientists are getting more and more interested in renewable energy sources, like biofuels.
Did you know? Biofuels have been around since the 1800s! For instance, Rudolf Diesel’s compression engine was designed to run on peanut oil. Also, Henry Ford’s famous mass-produced Model T Ford first ran on ethanol.
Fossil fuels versus biofuels: what’s the difference?
Fossil fuels are solid, liquid or gaseous forms of hydrocarbons (compounds made of carbon and hydrogen). They come from long dead biological materials. For example, they might come from plant and animal materials gathered buried under many of layers of mud, rock and sand. Over time, the heat of the Earth and the pressure of these layers turn the dead material into fossil fuels. People can then excavate and use fossil fuels for energy.
On the other hand, biofuels are solid, liquid or gaseous fuels derived from recently dead or living plant material and animal waste. According to the International Energy Agency, the most commonly used biofuel is bioethanol (ethanol produced from plants, usually agricultural crops). It makes up over 90 percent of all biofuel usage. However, there are several other kinds of biofuels. You may have heard of some of them, like vegetable oil and peanut oil.
Did you know? Yeast can only ferment sugar into bioethanol in anaerobic (no oxygen) conditions.
What’s so great about biofuels?
As I already mentioned, fossil fuels won’t be available forever. Not only that, they’re also bad for the environment. Burning fossil fuels releases an enormous amount of greenhouse gases, like carbon dioxide, into the environment. This contributes to global warming. Biofuel production can sometimes cause less carbon dioxide. For example, carbon dioxide emissions are 40 to 60 percent lower with biodiesel production than with diesel production.
People already have access to other alternative energy sources, like wind and solar energy. Because they’re renewable, these sources are also sustainable. Biofuels are renewable, too. In other words, you can grow plant raw materials again and again to produce biofuels continuously.
Although people can excavate more fossil fuels, they can’t easily create them. Once the fossil fuel deposits on Earth are completely used up, they’ll be gone for a very long time. And you can substitute biofuels for fossil fuels in many ways. That’s why researchers are so interested in them!
Did you know? Bioethanol can be a first-generation or second-generation biofuel. It’s a first-generation biofuel when it’s made from an edible material like sugar or wheat. It’s a second-generation biofuel when it’s made from non-edible materials like cellulose.
How are biofuels produced?
Scientists divide biofuels into three generations, depending on the raw materials used to produce them. First-generation biofuels are made mainly from food-related sources. Examples include starch from cereal plants like corn and wheat, sugar from sugar cane, vegetable oils and animal fats. Fuel can be made from these substances in many ways, including through the help of microorganisms (bacteria and other tiny organisms). For example, a fungus called Saccharomyces cerevisiae (yeast) can ferment sugar into bioethanol.
Second-generation biofuels are produced from non-food sources. They are mainly made from cellulosic materials (inedible parts of plants). That’s why they’re also called cellulosic biofuels. Crop residues (what’s left over after the edible part of a crop is harvested), wood and straw are examples of things that can produce cellulosic biofuels.
Third-generation biofuels are produced by certain species of algae. That’s why they’re also called algal fuels. Some algal species can secrete oily substances. These substances can be used as biofuels.
Algal biofuels have grabbed the interest of both manufacturers and scientists for a lot of reasons. For example, algal species often grow faster and produce much more oil than the best first-generation oil seed crops. However, large-scale algal biofuels are still very expensive to produce. Researchers are trying to develop better harvesting techniques and bioreactors (a type of instrument used to grow microorganisms).
The future of biofuels
So why isn’t everyone using biofuels? Part of the reason is that many biofuels are expensive to produce. But biofuels are also renewable, so they impact the environment much less than fossil fuels. If new technologies can make biofuel production cheaper and more efficient, biofuels might soon become one of the best substitutes for fossil fuels.