The Alternative fuels They are so named because they were designed primarily as alternatives to the use of fossil fuels in transportation. For instance: BTL, biodiesel, hydrogen.
A fuel is a material that has the ability to release energy in the form of heat, by going through a violent oxidation process.
The fuels release energy because, by breaking the chemical bonds of its molecules, the energy that held those bonds is free. This energy is called binding energy and it is a potential energy, that is, it affects any object outside the molecule itself. The moment that energy is released, in the case of fuels it is converted into heat.
This thermal energy (heat) can be used in various ways:
- Directly as heat (thermal energy). This is what happens for example when we use firewood (fuel) to light a fire.
- Turning it into motion (mechanical energy). Motors are devices that allow the energy released by fuels to be used to move various objects. For example, when we use gasoline (fuel) that through the engine can move a car. However, not all energy is used and combustion always produces thermal energy (heat).
Why are they necessary?
The traditional fuels, such as coal derivatives and petroleum derivatives (gasoline, diesel, etc.) release carbon dioxide gas during combustion, which is toxic in high concentrations.
In addition, even when it is not in significant concentrations, produces acid rain, damaging plants and affecting the quality of the soil. On the other hand, carbon dioxide in the atmosphere forms a layer that allows the sun’s heat to enter but prevents its exit, thus contributing to the greenhouse effect and global warming.
The objective alternative fuels is to provide a source of clean and sustainable energy, that is, it does not come from non-renewable resources, such as oil.
Alternative fuels are relatively new and currently the technologies necessary for its production and use are still in the preliminary stages of development. Therefore, although many alternative fuels are currently being used, many of them still require more energy for their production than that obtained from combustion. However, its possible uses are still being investigated since it is considered that with the appropriate technology its performance will improve.
Examples of alternative fuels
- BTL. Biomass to liquid. The acronym BTL comes from the English “Biomass to Liquids”. Biomass is living matter, that is, organisms. BTL is a type of synthetic fuel similar to fossil fuels (gasoline, kerosene, or diesel) that is produced from plants.
- Hydrogen. It is the simplest and smallest molecule: two hydrogen atoms. It combines with oxygen and other substances to be used as fuel. The advantage of using this substance as fuel is that it does not emit polluting gases. The downside is that it is not naturally free. For this reason, more energy is used to produce it than can be recovered in combustion. It can be used in fuel cells to generate electricity or heat. It can also be burned in combustion engines.
- Electric fuel. Cars capable of using electricity as fuel are currently being manufactured. The advantage is that electricity does not emit toxic gases. The downside is that vehicles with sufficient autonomy have not yet been created. That a vehicle is autonomous means that it can travel a great number of kilometers without refueling. This does not happen with electric cars. In addition, few cities have a system available for charging these vehicles, while gasoline is available throughout the world.
- Bioethanol. It is ethanol (alcohol produced by fermentation) that can be obtained from crops such as corn or soybeans. It is one of the favorite alternative fuel projects because its raw material is easily renewable. However, there is also a critical position that blames the use of crops in fuel production for the increase in food prices. Also, it has not yet been confirmed that it does not produce any toxic gas. However, it is highly probable that if it emits toxic gases they will be to a much lesser extent than fossil fuels. In the same way that it happens with hydrogen, another of the disadvantages of bioethanol is that the energy that is currently used in its production is greater than that obtained from fuel.
- Biodiesel. Liquid fuel that is produced specifically from lipids, that is, vegetable oils and animal fats. Unlike bioethanol, it is not produced by fermentation but by esterification and transesterification. The raw materials are usually rapeseed, oil palm and camelina oil. Animal fat has the disadvantage of producing a biodiesel that solidifies at higher than desirable temperatures.
- CTL. Charcoal to liquid. Coal can be turned into a liquid formed by hydrocarbons thanks to a chemical process called the Pott-Broche process. A high temperature, high pressure solvent is used on the charcoal. Hydrogen is then added and the product continues to be refined.