biofuels ‣ Data Nuggets

9.15.23

A difficult drought

A field of switchgrass studied by biofuels researchers.

The activities are as follows:

Most people use fossil fuels like natural gas, coal, and oil daily. We use them to generate much of the energy that gets us from place to place, power our homes, and more. Fossil fuels are very efficient at producing energy, but they also come with negative consequences. For example, when burned, they release greenhouse gases like carbon dioxide into our atmosphere. The right balance of greenhouse gasses is needed to keep our planet warm enough to live on. However, because we have burned so many fossil fuels, the earth has gotten too hot too fast, resulting in climate change. Scientists are looking for other ways to fuel our lives with less damage to our environment.

Substituting fossil fuels with biofuels is one of these options. Biofuels are fuels made from plants. Unlike fossil fuels, which take millions of years to form, biofuels are renewable. They are made from plants grown and harvested every few years. Using biofuels instead of fossil fuels can be better for our environment because they do not release ancient carbon like burning fossil fuels does. In addition, the plants made into biofuels take in carbon dioxide from the atmosphere as they grow.

To become biofuels, plants need to go through a series of chemical and physical processes. The sugar stored in plant cells must undergo fermentation. In this process, microorganisms, like yeast, transform the sugars into ethanol that can be used for fuels. Trey is a scientist at the Great Lakes Bioenergy Center. He is interested in seeing how yeast’s ability to transform sugar into fuel is affected by environmental conditions in fields, such as temperature and rainfall.

When there was a major drought in 2012, Trey used the opportunity to study the impacts of drought. The growing season had very high temperatures and very low rainfall. These conditions make it more difficult for plants to grow, including switchgrass, a prairie grass being studied as a potential biofuel source.

Trey knew that drought affects the amount and quality of switchgrass that can be harvested. He wanted to find out if drought also had effects on the ability of yeast to transform the plants’ sugars into ethanol. Stress from droughts is known to cause a build-up of compounds in plant cells that help them survive during drought. Trey thought that these extra compounds might harm the yeast or make it difficult for the yeast to break down the sugars during the fermentation process. Trey and his team predicted that if they fed yeast a sample of switchgrass grown during the 2012 drought, the yeast would struggle to ferment its sugars and produce fewer biofuels as a result.

To test their idea, the team studied two different sets of switchgrass samples that were grown and collected in Wisconsin. One set of switchgrass was grown in 2010 under normal conditions. The other set was grown during the 2012 drought. The team introduced the two samples to yeast in a controlled setting and performed four fermentation tests for each set of switchgrass. They recorded the amount of ethanol produced during each test.

Featured scientists: Trey Sato from the University of Wisconsin-Madison. Written by Marina Kerekes.

Flesch–Kincaid Reading Grade Level = 8.2

Additional teacher resources related to this Data Nugget include:

There are other Data Nuggets that share biofuels research. Search this table for “GLBRC” to find more! Some of the popular activities include:

Growing Energy: comparing biofuel crop biomass

Fertilizing biofuels may cause the release of greenhouse gases

The Great Lakes Bioenergy Research Center (GLBRC) has many biofuel-related resources available to K16 educators on their webpage.

For activities related specifically to this Data Nugget, see:

Fermentation in a Bag (elementary – high school level)
CB2E: Converting Cellulosic Biomass to Ethanol (high school – undergraduate level)

4.23.15

Growing energy: comparing biofuel crop biomass

The activities are as follows:

Éste Data Nugget también está disponible en Español:

Most of us use fossil fuels every day to power our cars, heat and cool our homes, and make many of the products we buy. Fossil fuels like coal, oil, and natural gas come from plants and animals that lived and died hundreds of millions of years ago – this is why they’re called “fossil” fuels! These ancient energy sources have many uses, but they also have a major problem. When we use them, fossil fuels release carbon dioxide into the atmosphere. As a greenhouse gas, carbon dioxide traps heat and warms the planet. To avoid the serious problems that come with a warmer climate, we need to transition away from fossil fuels and think of new, cleaner ways to power our world.

Biofuels are one of these alternatives. Biofuels are made out of the leaves and stems (called biomass) of plants that are alive and growing today. When harvested, the biomass can be converted into fuel. Plants take in carbon dioxide from the atmosphere to grow. It’s part of the process of photosynthesis. In that way, biofuels can create a balance between the carbon dioxide taken in by plants and what is released when burning fuels.

At the Great Lakes Bioenergy Research Center, scientists and engineers work together to study how to grow plants that take in as much carbon as possible while also producing useful biofuels. Gregg is one of these scientists and he wants to find out how much biomass can be harvested from different plants like corn, grasses, trees, and even weeds. Usually, the bigger and faster a plant grows, the more biomass they make. When more biomass is grown, more biofuels can be produced. Gregg is interested in learning how to produce the most biomass while not harming the environment.

While biofuels may sound like a great solution, Gregg is concerned with how growing them may affect the environment. Biofuels plants come with tradeoffs. Some, like corn, are great at quickly growing to huge heights – but to do this, they often need a lot of fertilizer and pesticides. These can harm the environment, cost farmers money, and may even release more of the greenhouse gasses we are trying to reduce. Other plants might not grow so fast or so big, but also don’t require as many chemicals to grow, and can benefit the environment in other ways, such as by providing habitat for animals. Many of those plants are perennials, meaning that they can grow back year after year without replanting (unlike corn). Common biofuel perennials like switchgrass, Miscanthus grass, prairie grasses, and poplar trees require fewer fertilizers and pesticides to grow, and less fossil fuel-powered equipment to grow and harvest them. Because of this, perennials might be a smart alternative to corn as a source of biofuels.

Gregg out in the WI experimental farm.

Believing in the power of perennials, Gregg thought that it might even be possible to get the same amount of biomass from perennials as is normally harvested from corn, but without using all of the extra chemicals and using less energy. To investigate his ideas, Gregg worked together with a team to design a very big experiment. The team grew many plots of biofuel plants on farms in Wisconsin and Michigan, knowing that the soils at the site in Wisconsin were more nutrient-rich and better for the plants they were studying than at the Michigan site. At each farm, they grew plots of corn, as well as five types of perennial plots: switchgrass, Miscanthus grass, a mix of prairie plant species, young poplar trees, and weeds. For five years, the scientists harvested, dried, and weighed the biomass from each plot every fall. Then, they did the math to find the average amount of biomass produced every year by each plot type at the Wisconsin and Michigan sites.

Featured scientist: Dr. Gregg Sanford from University of Wisconsin-Madison. Written with Marina Kerekes.

Flesch–Kincaid Reading Grade Level = 8.9

This Data Nugget was adapted from a data analysis activity developed by the Great Lakes Bioenergy Research Center (GLBRC). For a more detailed version of this lesson plan, including a supplemental reading, biomass harvest video and extension activities, click here.

This lesson can be paired with The Science of Farming research story to learn a bit more about the process of designing large-scale agricultural experiments that need to account for lots of variables.

For a classroom reading, click here to download an article written for the public on these research findings. Click here for the scientific publication. For more bioenergy lesson plans by the GLBRC, check out their education page.

Aerial view of GLBRC KBS LTER cellulosic biofuels research experiment; Photo Credit: KBS LTER, Michigan State University

For more photos of the GLBRC site in Michigan, click here.

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1.10.14

The ground has gas!

Measuring nitrogen (N2O) gas escaping from the soil in summer. Photo credit: Julie Doll, Michigan State University

The activities are as follows:

If you dig through soil, you’ll notice that soil is not hard like a rock, but contains many air pockets between soil grains. These spaces in the soil contain gases, which together are called the soil atmosphere. The soil atmosphere contains the same gases as the atmosphere that surrounds us above ground, but in different concentrations. It has the same amount of nitrogen, slightly less oxygen (O₂), 3-100 times more carbon dioxide (CO₂), and 5-30 times more nitrous oxide (N₂O, which is laughing gas!).

Measuring nitrogen (N2O) gas escaping from the soil in winter. Photo credit: Julie Doll Michigan State University.

Nitrous oxide and carbon dioxide are two greenhouse gasses responsible for much of the warming of global average temperatures. Sometimes soils give off, or emit, these greenhouse gases into the earth’s atmosphere, adding to climate change. Currently scientists are working to figure out why soils emit different amounts of these greenhouse gasses.

During the summer of 2010, Iurii and his fellow researchers at Michigan State University studied nitrous oxide (N₂O) emissions from farm soils. They measured three things: (1) the concentration of nitrous oxide 25 centimeters below the soil’s surface (2) the amount of nitrous oxide leaving the soil (3) and the average temperature on the days that nitrous oxide was measured. The scientists reasoned that the amount of nitrous oxide entering the atmosphere is positively associated with how much nitrous oxide is in the soil and on the soil temperature.

Featured scientist: Iurii Shcherbak from Michigan State University

Flesch–Kincaid Reading Grade Level = 9.2

More information on the research associated with this Data Nugget can be found here.

Data associated with this Data Nugget can be found on the MSU LTER website data tables under GLBRC Biofuel Cropping System Experiment. Bioenergy research classroom materials can be found here. More images can be found on the LTER website.

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1.9.14

Fertilizing biofuels may cause release of greenhouse gasses

An aerial view of the experiment at MSU where biofuels are grown. Photo credit: K. Stepnitz, MSU

The activities are as follows:

Greenhouse gases in our atmosphere, like carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), trap heat from the sun and warm the earth. We need some greenhouse gases to keep the planet warm enough for life. But today, the majority (97%) of scientists agree that the levels of greenhouse gases are getting dangerously high and are causing changes in our climate that may be hard for us to adjust to.

Scientist Leilei collecting samples of gasses released by the growing of biofuels. Photo credit: K. Stepnitz, MSU

When we burn fuels to heat and cool our homes or power our cars we release greenhouse gasses. Most of the energy used today comes from fossil fuels. These energy sources are called “fossil” fuels because they come from plants, algae, and animals that lived hundreds of millions of years ago! After they died, their tissues were buried and slowly turned into coal, oil, and natural gas. An important fact about fossil fuels is that when we use them, they release CO₂ into our atmosphere that was stored millions of years ago. The release of this stored carbon is adding more and more greenhouse gases to our atmosphere, and much faster than today’s plants and algae can remove during photosynthesis. In order to reduce the effects of climate change, we need to change the way we use energy and think of new ways to power our world.

One potential solution could be to grow our fuel instead of drilling for it. Biofuels are a potential substitute for fossil fuels. Biofuels, like fossil fuels, are made from the tissues of plants. The big difference is that they are made from plants that are alive and growing today. Unlike fossil fuels that emit CO₂, biofuel crops first remove CO₂ from the atmosphere as the plants grow and photosynthesize. When biofuels are burned for fuel, the CO₂ is emitted back into the atmosphere, balancing the total amount that was removed and released.

Scientists are interested in figuring out if biofuels make a good replacement for fossil fuels. It is still not clear if the plants that are used to produce biofuels are able to absorb enough CO₂ to offset all of the greenhouse gases that are emitted when biofuels are produced. Additional greenhouse gases are emitted when producing biofuels because it takes energy to plant, water, and harvest the crops, as well as to convert them into fuel. In order to maximize plant growth, many biofuel crops are fertilized by adding nitrogen (N) fertilizer to the soil. However, if there is too much nitrogen in the soil for the crops to take up, it may instead be released into the atmosphere as the gas nitrous oxide (N₂O). N₂O is a greenhouse gas with a global warming potential nearly 300 times higher than CO₂! Global warming potential is a relative measure of how much heat a greenhouse gas traps in the atmosphere.

Leilei is a scientist who researches whether biofuels make a good alternative to fossil fuels. He wondered what steps farmers could take to reduce the amount of N₂O released when growing biofuel crops. Leilei designed an experiment to determine how much N₂O is emitted when different amounts of nitrogen fertilizer are added to the soil. In other words, he wanted to know whether the amount of N₂O that is emitted into the atmosphere is associated with how much fertilizer is added to the field. To test this idea, he looked at fields of switchgrass, a perennial grass native to North America. Switchgrass is one of the most promising biofuel crops. The fields of switchgrass were first planted in 2008 as a part of a very large long-term study at the Kellogg Biological Station in southwest Michigan. The researchers set up eight fertilization treatments (0, 28, 56, 84, 112, 140, 168, and 196 kg N ha⁻¹) in four replicate fields of switchgrass, for a total of 32 research plots. Leilei measured how much N₂O was released by the soil in the 32 research plots for many years. Here we have two years of Leilei’s data.

Featured scientist: Leilei Ruan from Michigan State University

Flesch–Kincaid Reading Grade Level = 10.1

Additional teacher resources related to this Data Nugget:

Data related to this Data Nugget can be found on the MSU LTER website data tables under GLBRC Biofuel Cropping System Experiment. The data in this activity is the Trace Gas Fluxes from Static Chambers dataset which has N₂O, CO₂, and CH₄ data.
More information on LTER climate change research can be found here.
Bioenergy research classroom materials can be found here.
More images can be found on the LTER website.

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