Those interested in advanced transportation will be well aware of the massive potential of introducing such kinds of biofuels as microalgae-based fuels. With fossil fuels still making up a total of 80% of the world’s energy, they will also be aware of the challenges faced in making biofuels a viable replacement.
Currently, microalgae is considered to be one of the most promising renewable fuel sources. Algae-derived fuel can be used for three main types: biodiesel, bioethanol, and biogas.
Currently, microalgae is considered to be one of the most promising renewable fuel sources. Algae-derived fuel can be used for three main types: biodiesel, bioethanol, and biogas.
Biodiesel is created by the selection of microalgae with high oil content, which is then extracted to use as fuel. Bioethanol is created by the selection of microalgae with high sugar content, which are then cut, mashed and treated before having yeast introduced which turns it into fuel. Both biodiesel and bioethanol are liquid fuels which can be widely used in transportation.
Biogas primarily produces energy for commercial and domestic power use. Similar to bioethanol production, microalgae are cut and mashed at the beginning of the process. They are then fed into a tank where microorganisms are introduced, undertake anaerobic digestion and produce the useful methane gases.
Biofuels Pretreatment
Many organisations that are backing the use of microalgae-based fuels believe that increasing the effectiveness of algae pretreatment will also increase the efficacy of extraction of the fuel type. This is due to the complex cell wall structure of algae species and the difficulty with which sugars, oils and gases are extracted from them.
Studies have used various methods including thermal, mechanical, chemical and biological methods to break down the cells. Their results have shown that, with the microalgae species tested, all methods used were effective to some extent.
Efficient biomass pretreatment has been shown to increase the effective transformation of lignocelluloses into various biofuel products.
In fact, efficient biomass pretreatment has been shown to increase the effective transformation of lignocelluloses into various biofuel products. This is due to the increased digestibility of celluloses and hemicelluloses through the application of acid, alkali treatment, enzymatic hydrolysis, and steam explosion.
Primarily, the pretreatment process allows producers to maximise the release of sugars that are used primarily in the production of bioethanol (via the addition of yeast) and biogas (via the addition of microorganisms).
Fermentation Efficiency
In the development of biofuels, attention has also been drawn to increasing the efficiency of the fermentation process.
This attention has primarily been focused on the application of bacteria as an alternative to yeast in the production of bioethanol. The theory behind this is that the bacteria used would require less fermentation time than the use of traditional yeast fermentation, speeding up the process.
Testing of these theories is still not at a level for the theory to be widely accepted as a viable alternative. This is due to the fact that all microorganisms are limited by their ability to process certain classes of sugars or low yields of the end product, meaning bacteria may be more efficient at converting sugars but will convert less of them in comparison to yeast.
However, it is predicted that mid – long term development in technology will improve the fermentation efficiency of the bacteria, making it increasingly practical to produce more bioethanol in a shorter time period.
Gasification
There are number of advancements in gasification that are the cause for some excitement in the biofuel space.
To date, there has been an emphasis on biogas which is created on small-scale power generation for commercial and domestic use via downdraft gasification technology. This is a promising technology, although it requires a large investment in drying, sizing and densification processes.
Lab-scale tests have found that high density biomass and waste feedstock has a high potential for energy production when compared to low density biomass in term of cold gas efficiency and heating value of the producer gas.
Lab-scale tests have found that high density biomass and waste feedstock has a high potential for energy production when compared to low density biomass in term of cold gas efficiency and heating value of the producer gas.
Results indicate that the heating value of the producer gas of more than 6 MJ/Nm3 and cold gas efficiency of 80% can be achieved via this method.
Car Technology
There are countless media mentions around the innovative technologies seeking to eliminate the use of fossil fuels. These include ambitious plans for solar vehicles and other renewable or carbon-neutral technologies.
Biofuels offer a fossil fuel alternative which is widely applicable to the vehicles we already see on the road. For example, some cars, especially those manufactured after 2000 are likely to be able to run on a bioethanol mix. Biodiesel can also widely be used in any diesel car as a fuel alternative.
With this in mind, there is some concern around the viability of biofuels as governments start to ban the manufacture of cars powered by fossil fuels. However, this is actually likely to increase the viability of fossil fuels as an alternative fuel in hybrid cars during the transition.
Other types of transportation such as aviation, shipping and haulage also have limited electricity viability and are likely to produce bigger opportunities for biofuels moving into the future.
Clearly, biofuels are a promising alternative to the use of fossil fuels. Advancements in the area are making bioethanol, biodiesel and biogas increasing efficient and continually boosting their viability as a carbon-neutral fuel type.
