Alternative Energy- Biofuels

Biofuels are made by chemical reactions, heat, and fermentation to break down the starches, sugars and molecules in plant matter. Biofuels have been around since they started making cars, but because of the cheap prices of petroleum and gasoline, they have not been used. Gasoline and diesel are actually ancient Biofuels. Biofuels are a renewable source of energy, they reduce the excess carbon dioxide in the air, and no excess CO2 is added. The major plants that Biofuels are made of are corn, algae, and sugar cane.

Corn-based Biofuels

  • It is thought that corn-based biofuels will allow for the US to be completely independent from needing foreign oil, but this is not the case. Even if the entire US corn crop were to be used for biofuels it would only supply a small amount of the gasoline that the US needs.
  • Although biofuels can reduce some of the greenhouse gases, they will increase others. The farming of corn would require machinery that runs on fossil fuels, releasing CO2 into the atmosphere.
  • If more land were to be dedicated to the farming of corn for then the economies of rural communities would be solely based on this and that isn't good.
  • The increase in farming of the corn will erode soil, a higher use of fertilizers and pesticides, adding more nitrous oxide, and it would deplete water because of the irrigation that would be needed.
  • Corn-based ethanol doesn't create a "positive net energy balance" because it uses energy to make corn fertilizer, diesel that the tractors use, coal and natural gas that would be used in refineries, and the fuel it would take to transport the ethanol.
  • Transportation: Ethanol based biofuels are transportable, unlike most renewable energy sources, but the cost would be high. The infrastructures that are used now for gasoline could not support Ethanol biofuels, so new ones would need to be built. Railways would have to be made from the corn fields to refineries, but this causes a problem because the ethanol has corroding effects that would make it difficult to transport.
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  • Energy Content of Ethanol is around 1/3 less than that of gasoline. The miles-per-gallon will go down 2 to 3 percent and this means that you will need more of the biofuel to get the same distance than you would gasoline.
  • Price: Pure ethanol is usually cheaper than gasoline but there is a difference in the energy content. The U.S. is the leading producer of corn-based biofuel. gasoline retail price in the U.S. is $.3.03 whereas ethanol is only $2.65 per gallon. But to get the same energy content as gasoline, the ethanol would be $3.71, so therefore more expensive.


Algae as a Biofuel

- Algae has increasingly been studied as an alternative fuel source ever since the increase of oil prices
- Algae require three things to grow: water, CO2, and sunlight.
- There are more than 100,000 types of algae, and they can be found anywhere
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The current method of extracting fuel from Algae

- First, algae is grown in ponds or in plastic bags connected to coal factory emission pipes
Vertical vs. Closed-loop Growth
Vertical growth of algae
Vertical growth of algae
Closed-loop growth
Closed-loop growth

- Then algae is converted using one of two processes:

  • Hexane solvent method first squeezes oil from the algae (like squeezing orange juice from orange) and then adds hexane to filter the algae so that there are no chemical leftovers in the oil. This process extracts up to 95% of the oil in algae.
  • Supercritical fluids method adds heat and pressure to algae so that it is converted to the liquid-gas phase. Then, CO2 is added to convert algae completely into oil. This extracts 100% of the oil in algae, but also requires more equipment.
- In the final stage of fuel production, the algae oil goes through a process known as transesterification to create biodiesel fuel.

Other methods of obtaining fuel from algae

- Convert to liquid fuel
  • UCLA has successfully modified cyanobacterium to consume carbon dioxide and generate the liquid fuel isobutanol.
    • This algae can use solar energy to convert CO2 into liquid fuel
    • Can use CO2 to convert sunlight into isobutyraldehyde gas (which can be removed and converted into liquid) without having to deal with the algae biomass refinement.
- Convert to hydrogen
  • Scientists at UT are currently studying ways to use thermophilic algae to produce hydrogen in very high temperatures
  • Through this process they can use solar energy to convert hydrocarbons into ethanol or biodiesel
  • Because this process performs best under the intense sun of the desert, it does not take up any fertile land and can increase productivity for countries with lots of desert.

Carbon Dioxide

- Algae need carbon dioxide to grow. So despite the fact that processing it produces CO2, it has a present day carbon cycle which does not add more CO2 to the atmosphere.
- Atmospheric levels of CO2 do not offer enough concentrations of the gas to support exponential growth of algae.
- Researchers propose growing algae in coal factories; however, such proposals do not eliminate coal production processes.

Water Usage

- One method of growing algae in ponds requires lots of water.
- While some people argue that this process demands too much water to be sustainable, others claim that algae does not take up freshwater sources because it can grow in salt water as well as waste water
- Other ways of growing different types of algae does not require much water.
- More research is still needed in refining the processes.
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Algae Pro

- Can grow anywhere (extreme temperature, in any type of water, on wastes, in sewage, deserts, etc)
- Can reproduce extremely rapidly (double its mass in an hour under the right conditions) and thus can be harvested everyday
- Can produce 15x more oil per acre than other plants in some cases
- Uses CO2 and solar energy to grow as well as other pollutants
- The “waste” biomass of algae can be made into fertilizer and other useful products

  • Can potentially aid industries with their excess CO2 emission

Algae Con

- The current way of producing algae fuel involves industrial processing of algae, which ends up requiring more energy and emitting more greenhouse gases than using conventional fuels
- The industrial plants required to process algae is expensive
- Some forms of algae growth requires the same kinds of nutrients as other plants, which requires lots of energy and to produce as well as emits lots of pollutants
- Algae requires certain conditions to actually maximize its growth


- Though producing biofuel from algae helps the environment as well as decreases the dependence on nonrenewable fuels, a lot of research is still needed to refine the production process and make algae biofuel economically reasonable.