Ethanol fuel facts for kids

Ethanol fuel is a special type of alcohol used to power cars and other vehicles. It's the same kind of alcohol found in drinks, but it's made for fuel! We often mix it with gasoline or use it on its own. Making ethanol from plants like corn or sugarcane helps us use less fossil fuels and create less pollution.

Summary of the main ethanol blends used around the world in 2013

Corn vs Ethanol production in the United States      Total corn production (bushels) (left)      Corn used for Ethanol fuel (bushels) (left)

  Percent of corn used for Ethanol (right)

The Saab 9-3 SportCombi BioPower was the second E85 flexifuel model introduced by Saab in the Swedish market.

Brazil and the United States make most of the world's ethanol fuel. Many countries now mix ethanol into their car fuels. People have used ethanol as fuel since the early 1900s. Brazil started using it a lot in the 1970s.

Ethanol burns cleanly, turning into carbon dioxide and water. It also helps engines run smoothly. Most ethanol comes from fermenting (a process like brewing) sugars from plants. It's seen as a renewable energy source because plants can be regrown. However, growing crops for fuel can sometimes affect food prices or water supplies. Scientists are always looking for better ways to make ethanol even more sustainable.

Cars can use different mixtures of ethanol and gasoline. Some special cars, called flex-fuel vehicles, can even run on pure ethanol! Even though ethanol doesn't have as much energy as gasoline, it's often better for the environment because it burns cleaner.

How Ethanol Fuel Started and Is Used

Ethanol fuel has become much more common over the years. Between 2000 and 2007, the amount of ethanol made for transport tripled! Even though production dropped a bit in 2020, it's still a big part of fuel use.

Many countries, like Brazil, the United States, Canada, and those in Europe, use fuel mixed with ethanol. In the U.S., most cars can use fuel with up to 15% ethanol. Some special cars, called flex-fuel vehicles, can even run on 100% ethanol.

Brazil was a pioneer in using ethanol. In 1978, the Fiat 147 was the first car made to run completely on ethanol there. Since 1976, Brazil has required ethanol to be mixed with gasoline. Today, their fuel often contains about 25% ethanol. By 2011, Brazil had millions of flex-fuel cars and motorcycles using pure ethanol.

In 2011, the United States and Brazil were the biggest producers of ethanol fuel. Together, they made most of the world's supply.

How Ethanol is Made and Works

This is what an ethanol molecule looks like.

Ethanol is made through a process called fermentation. This is similar to how bread or some drinks are made. Tiny living things, like yeast, eat sugars from plants such as corn or sugarcane. As they eat the sugar, they create ethanol and carbon dioxide.

Here's a simple way to see it: Sugar from plants → Ethanol + Carbon Dioxide + Heat

After fermentation, the ethanol is cleaned and separated from water to make it ready for fuel.

When ethanol burns in an engine, it mixes with oxygen. This reaction creates carbon dioxide, water, and heat, which powers the engine.

Ethanol can also be made from other parts of plants, like cellulose (the tough parts of plant cell walls). This is called cellulosic ethanol. Scientists are working to make this process easier and more common.

Where Ethanol Comes From

Harvesting sugarcane, a common source for ethanol.

Switchgrass is another plant that can be used to make ethanol.

Most ethanol fuel, called bioethanol, comes from plants. These plants are called energy crops because they store energy from the sun. They are a renewable energy source because we can grow more of them.

Many different plants can be used to make ethanol, including:

• Sugarcane
• Corn
• Sugar beet
• Sorghum
• Switchgrass
• Cassava
• Wheat
• Even plant waste like straw!

Sometimes, ethanol can also be made from petroleum, like gasoline. This is called synthetic ethanol. However, most of the ethanol used for fuel today comes from plants.

Scientists are also exploring new ways to make ethanol. For example, some research looked into making ethanol directly from algae. This project was stopped in 2015, but new ideas are always being explored.

Making Ethanol Fuel

An ethanol plant in Claremont, Minnesota.

Ethanol plants across the United States.

Bioethanol is a renewable energy source made from plants. Common crops like sugarcane, potato, cassava, and corn are used. There's a lot of discussion about how well bioethanol can replace gasoline.

Some concerns include how growing large amounts of crops for fuel might affect food prices or the environment. However, the most common way to make ethanol is through fermentation.

The main steps to make ethanol on a large scale are:

• Fermentation: Using yeast to turn plant sugars into ethanol.
• Distillation: Heating the mixture to separate the ethanol from water.
• Dehydration: Removing almost all the remaining water to make it pure fuel.

Before fermentation, some plants need extra steps to turn their starches or cellulose into simple sugars. Special enzymes help with this process.

Fermentation Process

An ethanol plant in West Burlington, Iowa.

An ethanol plant in Piracicaba, Brazil.

Ethanol is made when tiny microbes, like yeast, ferment sugars. Right now, this process works best with simple sugars. Plants contain sugars, starch, and cellulose. Starch and cellulose can be turned into sugars, but it's easier and cheaper to use plants that already have a lot of sugar or starch, like sugarcane or corn.

Scientists are working on making cellulosic ethanol more affordable. This would allow us to use more parts of plants, like stalks and leaves, to make fuel.

Removing Water from Ethanol

After fermentation, the ethanol mixture still has a lot of water. To make it useful as fuel, most of this water must be removed. This is done through distillation, where the mixture is heated, and the ethanol evaporates and is collected.

However, distillation can only make ethanol about 95-96% pure. To get rid of even more water, other methods are used, like passing the ethanol vapor through special materials called molecular sieves. These sieves trap the water molecules, leaving behind purer ethanol. This process saves energy compared to older methods.

It's important to remove water because ethanol absorbs water from the air. If too much water gets into ethanol-gasoline blends, the fuel can separate, which is bad for engines.

How Ethanol Works in Engines

The first car powered by ethanol, a Chrysler Dodge 1800, at the Brazilian Aerospace Memorial.

Ethanol fuel has less energy per gallon than gasoline. This means a car running on pure ethanol might not go as far on the same amount of fuel as a car running on pure gasoline. However, ethanol has a higher octane rating. This allows engines to be designed to run more efficiently, making up for some of the energy difference.

For fuel mixtures like E10 (10% ethanol, 90% gasoline), the change in how much fuel a car uses is usually small. For E85 (85% ethanol), cars typically get lower mileage and need to refuel more often.

Cold Weather Challenges

In very cold weather, high ethanol blends can make it hard for engines to start. This is because ethanol doesn't evaporate as easily as gasoline when it's cold. To help with this, in places with harsh winters, the ethanol content in E85 fuel is sometimes reduced to E70 or E75.

The Brazilian 2008 Honda Civic flex-fuel has a small secondary gasoline tank for cold starts.

Brazilian flex-fuel cars, which can run on up to 100% ethanol, used to have a small extra gasoline tank. This tank would inject a bit of gasoline during cold starts to help the engine ignite. Newer flex-fuel engines have improved technology that often removes the need for this extra tank.

Common Fuel Mixtures

A price comparison table for hydrated ethanol and gasoline in Brazil.

EPA's E15 label, required on fuel pumps in the U.S.

Many countries require cars to use ethanol-gasoline mixtures. In Brazil, all light-duty vehicles are made to run on fuel with up to 25% ethanol (E25). In the United States, most cars can use E10 (10% ethanol). By 2010, over 90% of gasoline sold in the U.S. contained ethanol.

In 2011, the U.S. Environmental Protection Agency (EPA) allowed E15 (15% ethanol) to be sold for cars and light trucks made in 2001 or later.

Many modern cars and trucks are designed as flex-fuel vehicles. These vehicles can use any mix of gasoline and ethanol, from 0% to 85% (E85) in North America and Europe, or even 100% (E100) in Brazil. These cars have special computers and sensors that adjust the engine to run smoothly with different fuel mixtures.

India has also been increasing its use of ethanol-blended fuel. In 2021, India set a goal to use 20% ethanol-blended fuel by 2025. This means car manufacturers in India are now making vehicles that work well with these higher ethanol blends.

Other Engine Ideas

Scientists and engineers are always looking for new ways to use ethanol more efficiently. Some ideas include:

• ED95 Engines: Since 1989, some buses and trucks in Sweden have used special diesel-like engines that run on ED95, a mix of 93.6% ethanol with an ignition improver.
• Dual-Fuel Direct-Injection: This idea involves using a small, powerful engine that injects both gasoline and pure alcohol separately. The alcohol is used only when needed, like during acceleration, to boost power and efficiency. This could greatly reduce gasoline use.
• Fuel Cells: In 2016, Nissan announced plans to develop fuel cell vehicles that could run on ethanol instead of hydrogen. These vehicles would convert liquid ethanol into hydrogen right inside the car to power an electric motor.

Ethanol Production Around the World

The United States and Brazil are the world's biggest producers of ethanol fuel. In 2011, they made up over 87% of the world's total production. Many other countries, including Germany, China, Thailand, Canada, and India, are also increasing their ethanol production.

Annual Fuel Ethanol Production by Country (2007–2011) Top 10 Countries/Regional Blocks (millions of U.S. liquid gallons per year)
World rank	Country/region	2011	2010	2009	2008	2007
1	United States	13,900.00	13,231.00	10,938.00	9,235.00	6,485.00
2	Brazil	5,573.24	6,921.54	6,577.89	6,472.20	5,019.20
3	EU	1,199.31	1,176.88	1,039.52	733.60	570.30
4	China	554.76	541.55	541.55	501.90	486.00
5	Thailand			435.20	89.80	79.20
6	Canada	462.30	356.63	290.59	237.70	211.30
7	India			91.67	66.00	52.80
8	Colombia			83.21	79.30	74.90
9	Australia	87.20	66.04	56.80	26.40	26.40
10	Other			247.27
	World Total	22,356.09	22,946.87	19,534.99	17,335.20	13,101.70

Brazil's Ethanol Program

Since the 1970s, Brazil has had a very successful ethanol fuel program. This program has made Brazil the second-largest producer of ethanol (after the U.S.) and the biggest exporter. Brazil uses modern equipment and cheap sugarcane to make ethanol. They even use the leftover sugarcane waste to create heat and electricity for their plants. Today, no light vehicles in Brazil run on pure gasoline; they all use ethanol blends.

Ethanol and the Environment

Ethanol is considered a cleaner fuel than gasoline, but its production and use still have environmental effects.

Energy Balance

The energy balance of ethanol looks at how much energy is put into making it versus how much energy it provides when burned. For corn ethanol in the U.S., you get about 1.3 units of energy out for every 1 unit of fossil fuel energy put in. Sugarcane ethanol in Brazil has a much better balance, giving about 8 units of energy out for every 1 unit put in.

Air Pollution

Ethanol burns cleaner than regular gasoline. It produces less carbon monoxide and fewer tiny particles. However, burning ethanol can produce other chemicals like acetaldehyde, which can affect air quality in some areas.

Carbon Dioxide Emissions

UK government calculation of carbon intensity of corn bioethanol grown in the US and burnt in the UK

Graph of UK figures for the carbon intensity of bioethanol and fossil fuels. This graph assumes that all bioethanols are burnt in their country of origin and that previously existing cropland is used to grow the feedstock.

When ethanol is made and burned, it releases carbon dioxide, a greenhouse gas. However, the plants used to make ethanol absorb carbon dioxide as they grow. This helps to balance out the emissions.

Studies show that corn ethanol can reduce CO₂ emissions by about 7.4% compared to gasoline. Sugarcane ethanol can reduce emissions even more, by about 56%. Some carmakers report even higher reductions with bioethanol.

It's important to consider all parts of the process, from growing the crops to transporting the fuel, when calculating total emissions. Sometimes, preparing new land for crops can release greenhouse gases that take a long time to offset.

Land Use Changes

Making ethanol requires a lot of farmland. If all the corn in the U.S. were used for ethanol, it would only replace a small part of the country's gasoline use. There are concerns that growing crops for fuel could lead to deforestation or affect food supplies. It can also impact soil quality and water resources.

Scientists are working on cellulosic ethanol production. This method uses all parts of the plant, not just the kernels or sugary parts. This could help produce more ethanol from the same amount of land and reduce environmental impact.

How Different Crops Perform

As technology improves, making ethanol from different plants becomes more efficient. Scientists are researching ways to get more ethanol from each crop. They are also looking at using plants like switchgrass that can grow on land not suitable for food crops.

Benefits of Ethanol

One big reason the U.S. produces a lot of ethanol is to reduce its need for foreign oil. Ethanol is made from crops grown at home, which helps the country rely more on its own energy sources.

Ethanol production has also helped keep gasoline prices lower. Studies in 2008 suggested that ethanol made gasoline about $0.29 to $0.40 cheaper per gallon.

Special Uses and Projects

Motorsport

Ethanol fuel is becoming more popular in racing.

• The IndyCar Series started using a 10% ethanol blend in 2006 and a 98% blend in 2007.
• The American Le Mans Series switched to E10 in 2007 and allowed E85 in 2008.
• In 2011, NASCAR racing series began using E15 fuel.
• Australia's V8 Supercar championship uses Shell E85, and the Stock Car Brasil Championship runs on pure ethanol (E100).

Ethanol can even be used as rocket fuel in some lightweight racing aircraft!

Cooking Fuel

Project Gaia is a group that helps people in developing countries use alcohol-based fuels for cooking. This helps reduce fuel shortages, environmental damage, and health problems caused by traditional cooking fires. They work in countries like Ethiopia, Nigeria, and Brazil.

Research and Future Ideas

An ethanol plant in Turner County, South Dakota.

Scientists are always researching new ways to make ethanol. They are looking for different plant sources, better ways to process them, and new catalysts (substances that speed up chemical reactions).

Some exciting research areas include:

• Making ethanol from plant waste like wood chips, rice hulls, or sugarcane leftovers.
• Using special bacteria, like E.coli that have been genetically changed, to produce ethanol from corn stalks.
• Exploring how to make ethanol from municipal waste (trash) and even carbon dioxide.

These efforts aim to make ethanol production even more sustainable and efficient in the future.

See also