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Biofuel concept

Biofuel concept (Petmal, iStockphoto)

STEM in Context

What are the Pros and Cons of Ethanol Biofuel?

Krysta Levac & Let's Talk Science

Summary

Biofuels like ethanol might help fight climate change. But they can contribute to food insecurity and greenhouse gases in ways that might surprise you.

We use energy every day. We use it to turn on lights, to heat our homes, and to power cars. Most of the world’s energy comes from burning fossil fuels. But scientists and engineers are looking for more sustainable alternatives. 

Biofuels are becoming a popular alternative to traditional fossil fuel resources. But as with any new technology, it’s important to weigh the pros and the cons. Let’s consider some of these. 

What is Biofuel and How is it Used? 

Biofuels are derived from recently dead or living plant material and animal waste. This differs from fossil fuels, which are derived from long-dead plant and animal matter. The most commonly used biofuels are ethanol and biodiesel. They are produced from plants that are usually grown as crops. These plants make up the biomass that’s used as the feedstock in biofuel production. Feedstock is any material that is used to make biofuels. In North America, corn is the main type of feedstock used in ethanol production. 

Corn field in Ontario
Corn field in Ontario (Source: Illustratedjc [CC BY-SA 3.0]via Wikimedia Commons).

To produce ethanol from corn, the first step is to break down starch. Starch is a complex carbohydrate. To produce ethanol, it must be broken down into simple sugars like dextrose and glucose. A process called fermentation then converts these sugars to ethanol. 

Did you know?

Yeast ferments sugar into ethanol in anaerobic conditions. This means that the process can occur without oxygen!

Biodiesel is made from vegetable oils or animal fats. A reaction called transesterification is responsible for the conversion of plant oils to biodiesel. Transesterification is the reaction of an alcohol with oil or fat to produce fatty acid alkyl esters, otherwise known as biodiesel.

Canadian biorefineries have the capacity to produce 1.7 billion litres of ethanol per year. Most of this is mixed into gasoline. The majority of gasoline-powered vehicles built since the 1980s can run on a mixture of up to 10% ethanol (E10) without any engine modifications. Some North American car companies make Flexible Fuel, or Flex-Fuel, vehicles with modified engines. These engines can use mixtures of up to 85% ethanol and 15% gasoline (E85). 

Did you know?

The United States and Brazil are the world leaders in biofuel production. Together, they produce 70% of the world’s biofuels!

Canada’s Renewable Fuel Regulations were enacted in 2010. They require that non-renewable fossil fuel contain an average of 5% renewable fuel content. That 5% level is currently being met with corn and wheat ethanol (E5). What about the E85 blend that can be used in Flex-Fuel vehicles? Some Canadian companies with large fleets of vehicles use E85. But it is not yet widely available. There are only a handful of gas stations in Canada that sell E85. In contrast, there are over 3 000 gas stations with E85 pumps in the U.S. That may sound like a lot. But it is still less than 2% of total fuel stations. 

What are the pros of biofuels?

Ethanol is considered a renewable energy resource. That’s because new crops can be grown to replenish the feedstock needed to make it. On the other hand, fossil fuels take millions of years to produce. They are considered a nonrenewable resource because once they’re used up, that’s it!

One of the main benefits of using biofuels is that it reduces greenhouse gas (GHG) emissions. In 2017, the oil and gas and transportation sectors accounted for over 50% of Canada’s total GHG emissions. Most of these were carbon dioxide (CO2) released by burning fossil fuels, such as gasoline.

What is the carbon cycle?

The carbon cycle is responsible for the cycling of carbon throughout the environment. All organic matter contains carbon. When plants and animals die, carbon is trapped underground as they turn into fossil fuels. This means that fossil fuels are a carbon sink. When fossil fuels are burned, the carbon is released into the air in the form of carbon dioxide (CO2). 

The carbon cycle
The carbon cycle (Source: Let’s Talk Science, Derivative work: FischX [Public domain] via Wikimedia Commons).

 

Graphic - Text version

In the carbon cycle, carbon moves from the atmosphere to the sediments on Earth, and back. As carbon reaches the Earth, dissolved organic carbon gets into both deep ocean and surface ocean. Carbon is released back into the atmosphere through natural processes, like vegetation photosynthesis, and through human-caused processes, like industrial processes that produce fossil fuels.

 

The CO2 that is released into the atmosphere when fossil fuels are burned produces powerful GHGs. These GHGs contribute to climate change. Unfortunately, there is no way to turn CO2 back into fossil fuels. 

CO2 is produced when biofuels are burned, too. But some of the CO2 released by burning biofuels is absorbed by the new crop of feedstock through the process of photosynthesis. The CO2 is incorporated into the sugar molecules that the plants produce. These will eventually be converted back into biofuel. Because of this, ethanol is considered to be carbon neutral

Did you know?

It has been found that ethanol yields 25% more energy than is put into its production, and biodiesel yields a whopping 93%!

What are the cons of biofuels?

Biofuels come with concerns, too. Some concerns include energy balance, the food versus fuel debate, and the availability of biofuels.

Do biofuels have a negative energy balance or a positive energy balance?

Ethanol itself is considered carbon neutral. But the process of producing it is not. Fossil fuels are often used throughout the process of producing biofuels. For example, farmers’ tractors use diesel fuel. The trucks that transport the feedstock to biorefineries use diesel fuel. The biorefineries themselves sometimes use fossil fuels for power. If the input energy to make a fuel is greater than the output energy, that fuel has a negative energy balance. That’s not good. If the output energy is greater than the input energy, the fuel has a positive energy balance. That is good.

Scientists must do life cycle analyses to fully understand the GHG impact of biofuels compared to fossil fuels. In the early days of ethanol production, many studies found that it had a negative energy balance. However, recent Canadian and American life cycle analyses have found a modestly positive energy balance in the corn ethanol production industry. The improvement is largely due to newer, energy-efficient biorefineries. 

What is the “Food vs. Fuel Debate”?

Biofuels come with some economical and ethical concerns. Specifically, what happens if people use cropland to grow fuel biomass instead of food? This relates to food security. Critics of first generation biofuels argue that using food crops for fuel production increases food prices. This makes it more difficult for people to afford to eat healthily. 

A commodity is anything valuable that is bought, sold or traded. Let’s look at the example of one commodity: corn. 

Corn is a renewable feedstock. But some harvests are more successful than others. That means its supply can vary. When agricultural conditions are good, there may be plenty of corn. There may be enough for human food, animal feed, and biofuel production. But sometimes harvests suffer due to conditions like droughts, floods, and cold periods. At these times, the supply of corn may go down. And when the supply of a commodity goes down, the price goes up.

Of course, this ‘Food vs. Fuel’ debate has another side. Some studies show that global food wastage is a much bigger issue for food security than competition with biofuels is. Some scientists have even suggested that food that would normally go to waste should be diverted to the biofuel industry instead

Biofuels can affect food and resources for other organisms, too. It takes a lot of land to produce biofuels. Clearing land for agriculture can have big impacts on the environment, and the plant and animal life living there. 

Summing up

There are certainly no easy answers when it comes to the debate between fossil fuels and biofuels. The global food chain and the biofuel industry are interconnected in complicated ways. But people are more and more aware of the possible drawbacks of first generation food crop-based biofuels. There is also a push towards second generation biofuels instead. These use non-food feedstocks like agricultural, restaurant, and municipal waste. 

 

Starting Points

Connecting and Relating

  • Have you or your parents ever filled up the car with ethanol? Why or why not?
  • Can you purchase E85 fuel at your local gas station? How often do you see vehicles filling up with ethanol fuel?
Connecting and Relating

  • Have you or your parents ever filled up the car with ethanol? Why or why not?
  • Can you purchase E85 fuel at your local gas station? How often do you see vehicles filling up with ethanol fuel?
Relating Science and Technology to Society and the Environment

  • Do you think that farmland should be diverted to produce crops for biofuels instead of food for animal or human consumption? 
  • What are the potential risks of using starch crops for the production of biofuels?
  • Is it currently worthwhile for people to invest in cars that can use ethanol fuel? How does the availability of an ethanol fuel option (e.g., E85) at the pump impact on the sales and purchases of ethanol option vehicles? 
Relating Science and Technology to Society and the Environment

  • Do you think that farmland should be diverted to produce crops for biofuels instead of food for animal or human consumption? 
  • What are the potential risks of using starch crops for the production of biofuels?
  • Is it currently worthwhile for people to invest in cars that can use ethanol fuel? How does the availability of an ethanol fuel option (e.g., E85) at the pump impact on the sales and purchases of ethanol option vehicles? 
Exploring Concepts

  • How does fossil fuel differ from biofuel? 
  • How does biodiesel production differ from bioethanol production?
  • What does carbon neutral mean?
  • Why is a life cycle analysis necessary to show if a particular type of biofuel actually reduces greenhouse gases?
  • How can biofuel production contribute to GHG production?
  • How does the use of E85 fuels in vehicles affect their fuel efficiency (i.e., gas mileage)?
Exploring Concepts

  • How does fossil fuel differ from biofuel? 
  • How does biodiesel production differ from bioethanol production?
  • What does carbon neutral mean?
  • Why is a life cycle analysis necessary to show if a particular type of biofuel actually reduces greenhouse gases?
  • How can biofuel production contribute to GHG production?
  • How does the use of E85 fuels in vehicles affect their fuel efficiency (i.e., gas mileage)?
Media Literacy

  • Companies like Exxon have been doing promotional advertising about third-generation algal biofuels in recent years. Why would a company that manufactures and sells traditional fossil fuels be promoting an alternative biofuel? Are there other fuel companies that are doing similar promotional advertising? 

Media Literacy

  • Companies like Exxon have been doing promotional advertising about third-generation algal biofuels in recent years. Why would a company that manufactures and sells traditional fossil fuels be promoting an alternative biofuel? Are there other fuel companies that are doing similar promotional advertising? 

Teaching Suggestions:
  • This article can be used to support teaching and learning of Chemistry, Biology, Environmental Science and Climate Change related to biofuels, carbon cycle, greenhouse gases, climate change and food security. Concepts introduced include fossil fuels, sustainable, biofuels, ethanol, biodiesel, feedstock, starch, fermentation, transesterification, E10, E85, renewable energy, non-renewable resource, greenhouse gas (GHG), gasoline, carbon cycle, carbon sink, climate change, photosynthesis, carbon neutral, negative energy balance, positive energy balance, life cycle analysis, food security, first generation biofuels and commodity.
  • After reading this article, teachers could have students complete a Concept Definition Web learning strategy to consolidate their understanding of the concept of biofuels. Ready-to-use Concept Definition Web reproducibles are available in [Google doc] and [PDF] formats.
  • To explore issues surrounding the production and use of biofuels, teachers could have students discuss the positive and negative aspects of biofuels using a Pros & Cons Organizer learning strategy. Ready-to-use Pros & Cons Organizer reproducibles are available in [Google doc] and [PDF] formats. 
Teaching Suggestions:
  • This article can be used to support teaching and learning of Chemistry, Biology, Environmental Science and Climate Change related to biofuels, carbon cycle, greenhouse gases, climate change and food security. Concepts introduced include fossil fuels, sustainable, biofuels, ethanol, biodiesel, feedstock, starch, fermentation, transesterification, E10, E85, renewable energy, non-renewable resource, greenhouse gas (GHG), gasoline, carbon cycle, carbon sink, climate change, photosynthesis, carbon neutral, negative energy balance, positive energy balance, life cycle analysis, food security, first generation biofuels and commodity.
  • After reading this article, teachers could have students complete a Concept Definition Web learning strategy to consolidate their understanding of the concept of biofuels. Ready-to-use Concept Definition Web reproducibles are available in [Google doc] and [PDF] formats.
  • To explore issues surrounding the production and use of biofuels, teachers could have students discuss the positive and negative aspects of biofuels using a Pros & Cons Organizer learning strategy. Ready-to-use Pros & Cons Organizer reproducibles are available in [Google doc] and [PDF] formats. 

Learn more

Life Cycles of Fuels (2017)

This Wisconsin Energy Institute video (8:19 min.) explains the process by which fossil fuels and biofuels are made and analyzes the life cycles of various forms of fuel.

Renewable Industries Canada (2019)

Official Website of the RIC, which includes information about renewable industries in Canada, including biofuel usage and advancement.

Electric Charging and Alternative Fuelling Stations Locator (2019)

Natural Resources Canada has an interactive map showing where electric charging and other alternative fueling stations (such as ethanol and biodiesel) can be found throughout North America.

References

Energy Community.org. (n.d.). Energy balance tables.

European Technology. (n.d.). Food vs. fuel debate.

Gerpen, J. V. (2019, April 3). Farm energy. eXtension.

Grain Farmers of Ontario. (2011, April). Food vs. fuel.

Lardon, L., Helias, A., Sialve, B., Steyer, J. P., & Bernard, O. (2009, July 27). Life-cycle assessment of biodiesel production from microalgae. Environmental Science & Technology, 43(17), 6475-6481. DOI: 10.1021/es900705j

Natural Resources Canada. (2018, December 19). Ethanol.

PennState College of Earth and Mineral Sciences. (n.d.). How corn is processed to make ethanol.

United States Department of Agriculture. (2016, February). 2015 energy balance for the corn-ethanol industry.