Waste Not, Want Not — Alternative Fuels From Unusual Sources

tobacco plants

Oft-maligned tobacco plants could be a source of biofuels in the future. (Photo credit: Photodisc/Getty Images)

Today, the fuels we might call alternate were once prime candidates to supply many of our energy needs.

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Fuel from Algae

Could you imagine filling up your car with fuel made from algae? It just might happen. (Photo Credit: Julie Fisher/iStockphoto)

Could pond scum be the next miracle fuel? If research scientists are successful, you may one day fuel your car with biofuel made from algae. In fact, commercial airlines have already started flight testing the new fuel using blends of standard fuel and algae-based biofuel.

Researchers at several start-up businesses in the United States and around the world are studying algae and its use as a biofuel. Algae produces oil as a part of the photosynthetic process. A variety of methods are being used to cultivate the algae. Some companies are growing algae in the Sun using clear pipelines called bioreactors. Other companies are cultivating algae under natural conditions in ponds. Solazyme, a company located in San Francisco, has developed a method to grow algae without a need for the Sun or artificial lights.

The algae cultivated by researchers at Solazyme is grown inside stainless steel vats. The scientists use genetically-modified strains of algae that get energy from sugar rather than from sunlight. The normal metabolic processes undergone by the algae create an oil that can be further processed into a variety of biofuels.

Making fuel from algae is not a new idea. In fact, the U.S. Department of Energy headed research into algae’s use as a biofuel beginning in the late 1970s. While research in previous years focused on using algae in situ (that is, where it exists naturally), today’s research is focused on enhancing algae’s ability to make oil and, as illustrated above, cultivating it outside of natural conditions.

Researchers are studying ways to efficiently make biofuel from algae. (Photo Credit: Frank Schoettke/iStockPhoto)

For example, researchers at the University of Virginia are studying ways to enhance the growth rate of algae used to make biofuel. The research team’s current hypothesis is that feeding algae carbon dioxide and other organic matter will significantly increase its growth rate and oil production. The latter method mentioned could be used as a means to reduce human waste and atmospheric carbon dioxide, while producing a usable fuel source.

What makes algae a better source of biofuel than other types of vegetation? Research indicates that algae produces more oil per acre than corn or switchgrass, two other popular sources of biofuel. In addition, algae can be grown under a variety of conditions and in a variety of locations. This characteristic makes algae suitable for growth in places where other plants would be unable to grow.

Biofuel made from algae has already been shown to be a successful replacement for typical petroleum-based fuel in cars and airplanes. Continental, Air New Zealand, Japan Airlines, and Virgin Airlines have used a mixture of biofuel and standard fuel in test flight demonstrations. Though the time when you can fill your car’s tank with fuel made from algae may still be far off in the future, current research indicates that algal-based biofuel is a clear possibility.

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Genetically-Modified Fuel

Researchers at Pennsylvania State University have grown poplar trees that contain a gene from a very different plant: a green bean! The green bean gene causes changes in the makeup of the poplar trees lignin. Lignin is a material that is normally found together with cellulose in the woody parts of plants. Lignin is important for maintaining a plants structure and protecting the plant from microorganisms.

Plant cellulose stores a lot of energy. This energy is harvested to make ethanol, a fuel that can be used in some vehicles and for other energy needs, too. To access the energy in cellulose, workers must first break apart the lignin to get the cellulose. This process is hard and expensive to do! However, the green bean gene changes the lignin in such a way that accessing the cellulose is much easier and cheaper to do.

The Pennsylvania State University researchers found that their work has other uses, too. Some plants, such as ryegrass and clover, are not good for feeding to animals because the high amount of lignin is hard for the animals to digest. By genetically modifying these plants, their lignin would be more digestible to the animals.

Genetically modified plants must be approved by the federal Food and Drug Administration (FDA) before they can be sold and used outside of research facilities. Why do you think that is?

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Fuel from E. coli Poo?

Researchers at a California biotechnology company have developed bacteria that excrete diesel fuel as a waste product. The scientists’ research is based on the same principle behind the formation of fossil fuels. As you may recall, fossil fuels form from the decomposition of plants and other organic materials over timetypically over a period of hundreds of millions of years or more. Because fossil fuels take such a long time to form, scientists (and the general public) are worried about the potential depletion of fossil fuels in the near future. This depletion is especially worrying as fossil fuels are a major source of energy used to heat homes and power vehicles across the world.

Biofuels, which are fuels made from renewable resources, have been promoted as one possible viable alternative to fossil fuels. One example of a biofuel is ethanol, which is made from organic material such as corn or switchgrass. Although relatively easily-produced, ethanol currently requires a separate system for distribution as it can corrode pipes typically used to distribute oil. Vehicle engines also need to be modified in order to use ethanol effectively as a fuel source. Given these constraints, researchers have continued to look for another viable alternative to fossil fuels.

Researchers at LS9 Inc, a private biotech firm, genetically altered a harmless form of E. coli bacteria to produce diesel fuel after being fed plant material. Almost any plant material works as a food source for the bacteria–including materials such as wood chips, which would otherwise be thrown away as a waste product from the lumber industry. This innovation gets around the complaint from some biofuel-industry critics that resources that could be used as food for humans should not be used to make fuel.

At the moment, the process of making diesel fuel from bacteria excrement is not ready for wide-scale production–the researchers think that large-scale production may become a reality in three to four years. Even so, researchers realize that the production of fuel from bacteria is not the end-all solution to the problem of finding alternatives to fossil fuels. However, they hope that the results of their research can, at the very least, be a part of the solution, and perhaps lead to even more innovations in the future.

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Biofuels of the Future

Switchgrass grown for biofuel production in Nebraska. (Credit: Peggy Greb/USDA)

Introduction to Biofuels

The growing concern over climate change and greenhouse gases is forcing people to take a hard look at how we produce and use energy. The burning of fossil fuels such as petroleum and coal adds tremendous amounts of carbon dioxide to the atmosphere. Many industrial nations now face the challenge of reducing dependence on oil and coal and finding alternative fuels. One popular alternative fuel is ethanol, a combustible “biofuel” that is produced by the fermentation of plant matter. Nonrenewable fossil fuels form over millions of years from dead organic material. In comparison, biofuels are a renewable resource that are made from recently-harvested organic matter.

Ethanol burns more cleanly than gasoline and coal, producing less carbon dioxide per unit of energy. But some types of ethanol are better than others, and some ways of producing ethanol can cause their own environmental problems.

Biofuels vs. Fossil Fuels

For example, Brazilians are currently producing ethanol from sugarcane, which is easy to grow in Brazil’s tropical climate. The problem with this is that areas of the Amazon rain forest are being cut down in order to clear more land for growing sugarcane. The last thing environmentalists want is for the world to lose one of its richest ecosystems–not to mention a large “sink” for carbon dioxidejust to produce a fuel that burns more cleanly than gasoline. A solution to an environmental problem should, ideally, not create another environmental problem.

Costs and Benefits of Biofuels

Scientists at the Smithsonian Tropical Research Institute wanted to weed out less efficient biofuels from more efficient ones. They analyzed the output and environmental costs of 26 different biofuels and how the plants they come from are grown. Biofuels made from Brazilian soybean, Malaysian palm oil, and U.S. corn were found to be worse for the environment than gasoline. The production of biofuel from plant sources such as those requires high energy input and also negatively impacts the environment. Growing and processing corn, for example, requires large amounts of nitrogen fertilizer and diesel fuel to power tractors. Processing the corn into ethanol also requires a lot of energy. The energy output of corn-based ethanol does not make up for the investment of this energy. So while these biofuels are good in that they aren’t made from fossil fuels, their use does not combat climate change or environmental degradation.

“Different biofuels vary enormously in how eco-friendly they are,” said Dr. William Laurance, one of the Smithsonian scientists who led the study. “We need to be smart and promote the right biofuels, or we won’t be helping the environment much at all.”

Energy-Efficient Switchgrass

Some biofuels do seem to have a much better ratio of clean energy output to energy and environmental impact. Switchgrass, for example, is native to the U.S. and grows very easily. Under the guidance of the U.S. Department of Agriculture, farmers in North Dakota and Nebraska grew fields of switchgrass and monitored exactly how much energy went into the process. The experiment yielded the kind of result biofuel engineers were hoping for. The estimated energy available from ethanol made from the switchgrass was more than five times the energy that went into its production.

In Nebraska, a technician harvests switchgrass to evaluate yield potential. (Credit: Peggy Greb/USDA)

The U.S. Department of Energy is now funding the construction of six biofuel refineries that will be able to process cellulosic, or plant-fiber, biofuel materials such as switchgrass, wood chips, sawdust, and other similar products.

“Cost-competitive, energy-responsible cellulosic ethanol made from switchgrass or from forestry waste like sawdust and wood chips requires a more complex refining process but it’s worth the investment,” notes Samuel Bodman, Secretary of the Department of Energy. “Cellulosic ethanol contains more net energy and emits significantly fewer greenhouse gases than ethanol made from corn.”

Switchgrass is also superior to corn and other biofuel sources because its roots remain in the ground after the grass is cut. The roots continue to absorb carbon dioxide and store it in the soil. Corn and wheat roots are only a few feet long, but switchgrass roots can grow as long as eight feet. Scientists estimate that 94 percent of the carbon dioxide emitted into the atmosphere during the cultivation and burning of switchgrass ethanol could be recaptured and stored by the plant. In this way, this plant could be a very efficient and environmentally-friendly source of energy in the future.

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