This captured biogas then must be refined further to remove water, carbon dioxide, and other elements so that it meets the standard needed to fuel natural-gas-powered vehicles. A variety of materials, or feedstocks, can be used to make biofuels. Though corn and sugarcane are well-established ethanol feedstocks, the process of growing the crops, making fertilizers and pesticides, and processing the plants into fuel consumes a lot of energy—so much energy that there is debate about whether ethanol from corn actually provides enough of an environmental benefit to be worth the investment.
So scientists and startups are exploring other materials that have the potential to serve as fuel without the accompanying concerns about food supply and environmental impact. Cellulosic ethanol , for example, uses corn stover, wood waste, or other plant material that would not be used otherwise.
Other potential biofuel feedstocks include grasses , algae , animal waste , cooking grease , and wastewater sludge , but research continues to find the most efficient and cost-effective ways to transform them into usable fuel.
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Go Further. Animals Climate change is shrinking many Amazonian birds. As a result, other national parks began using biodiesel in their vehicles Pahl, , pp. At this time, one problem with biodiesel was its often uneven quality.
This allowed engine manufacturers and fleet managers to feel confident that biodiesel would satisfy their quality requirements. Because biodiesel and other biofuels can help countries reduce their dependence on imported fossil fuels, and because biofuels frequently produce less air pollution and less net carbon emissions than fossil fuels, governments around the world became very interested in promoting their use.
Governments issued mandates requiring the use of biofuels and offered tax credits for their use. As a result, production of biodiesel grew rapidly. By , there were 25 biodiesel plants in the United States, and by , the National Biodiesel Board listed over manufacturers on its Web site.
Worldwide, biodiesel production grew from about 1 billion liters in to 6 billion liters in Pahl, , p. Government policy has been very important to the development of the biodiesel industry in the United States.
The Energy Policy Act of , which was intended to reduce the need for imported petroleum, required government fleets to purchase alternatively fueled vehicles. More recently, the National Renewable Fuel Standard, released in , requires petroleum companies to buy alternative fuels in proportion to their sales of traditional petroleum fuels. This is expected to cause a similar boost in biodiesel sales. Glycerin, a co-product, is a sugar commonly used in the manufacture of pharmaceuticals and cosmetics.
Raw or refined plant oil, or recycled greases that have not been processed into biodiesel, are not biodiesel and should not be used as vehicle fuel.
Fats and oils triglycerides are much more viscous than biodiesel, and low-level vegetable oil blends can cause long-term engine deposits, ring sticking, lube-oil gelling, and other maintenance problems that can reduce engine life.
Research is being conducted on developing algae as a potential biodiesel feedstock. The two most common types of biofuels in use today are ethanol and biodiesel, both of which represent the first generation of biofuel technology. The Bioenergy Technologies Office BETO is collaborating with industry to develop next-generation biofuels made from non-food cellulosic and algae-based resources.
Over the past decade, BETO focused on cellulosic ethanol, investing in technology advances throughout the supply chain. These activities successfully validated critical technologies for cellulosic ethanol production. Watch the Energy Video: Biofuels to learn more.
Most ethanol is made from plant starches and sugars, but scientists are continuing to develop technologies that would allow for the use of cellulose and hemicellulose, the non-edible fibrous material that constitutes the bulk of plant matter. In fact, several commercial-scale cellulosic ethanol biorefineries are currently operational in the United States. The common method for converting biomass into ethanol is called fermentation. During fermentation, microorganisms e.
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