Cleaner Fuels: Displacing Conventional Gasoline
We can reduce U.S. oil use by filling up our cars with fuels other than gasoline, including electricity, biofuels, diesel, and natural gas. But not all of these substitutes are equally promising. Some, such as electricity and cellulosic biofuels made from non-food sources, offer enormous potential to sustainably reduce U.S. oil consumption and global warming emissions, while others can create just as many problems as they solve.
The Potential of Biofuels
Biofuels are produced from organic matter like corn, grasses, vegetable oil, agricultural waste, and even garbage. They hold great potential, but their environmental benefits vary depending on the source material and the methods used to produce them.
Corn-based ethanol is the largest source of biofuel in the United States and the world, but the environmental and food supply problems caused by expanding corn cultivation to produce fuel make it ineffective as a strategy to reduce global warming emissions. Advanced biofuels made from non-food sources such as garbage, perennial grasses, and waste materials from agriculture and forestry (known as cellulosic biofuels) offer the greatest potential to achieve significant emissions reductions with minimal environmental impacts.
Today corn ethanol makes up about 10 percent of the gasoline in the United States, but to responsibly expand the role of biofuels and reduce oil consumption will require moving beyond food-based fuels. To get there we need smart government policy, funding, and support to develop the required technology. The Billion Gallon Challenge is a UCS effort to build the support and policies needed to bring promising cellulosic biofuels to market.
Learn More:
- Smart Bioenergy: Guiding Sustainable Bio-based Energy and Fuels Development
- Smart Biofuel Production: Meeting the Billion Gallon Challenge Video
- Biodiesel Basics
- Food Crops as Transportation Fuel
- The Truth about Ethanol
- Benefits and Limitations of Flex Fuel Vehicles
Land, Water, and Biofuels
Biofuels have the potential to produce fewer global warming emissions than conventional gasoline, but their total carbon footprint includes more than just what comes out of the tailpipe. It also includes emissions from farms, factories, and any land use changes required to grow the necessary source material.
When crop-based biofuels contribute to deforestation or other damaging land conversions, the overall emissions benefits can be compromised or even eliminated. Biofuel production also has impacts on water supplies, which can affect both the quality and availability of freshwater resources.
Learn More:
- Land Use Changes and Biofuels
- Managing the Rising Tide of Biofuels (PDF)
- Corn Ethanol’s Threat to Freshwater Resources (PDF)
Cleaner Diesel
Diesel powers most of America’s freight transportation and contributes a disproportionate share of air pollution. Cleaner forms of diesel can help reduce its pollution impacts.
Learn More:
What about Natural Gas?
Natural gas can play a role in reducing global warming pollution, but using it for transportation fuel does not represent one of the best climate solutions. For example, a natural gas-powered Honda Civic delivers about a 15 percent reduction in global warming pollution compared with a conventional gasoline-powered Civic, but a gasoline-electric Civic hybrid costs less and delivers a 30 percent reduction in emissions.
While it can make sense to use natural gas for vehicles fueled in a central location, such as taxis or delivery vehicles, expanding natural gas use in passenger vehicles would require major investments in new fueling infrastructure that would become obsolete as cleaner technologies come to market. A better use for natural gas in the transportation sector would be as a resource to generate cleaner electricity for plug-in vehicles or hydrogen for fuel cell vehicles.
