A recent National Research Council report says that by the year 2050, the U.S. may be able to reduce petroleum consumption and greenhouse gas emissions by 80% from cars and small trucks with a combination of more efficient vehicles, and the use of alternative fuels such as biofuels, electricity, and hydrogen.
The study was sponsored by the U.S. Department of Energy’s Office of Efficiency and Renewable Energy. Not surprisingly, it also calls for “strong government policies to overcome high costs and influence consumer choices.”
The Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering. It said, “while achieving these goals will be difficult, improving technologies driven by strong and effective policies could make deep reductions possible.”
“To reach the 2050 goals for reducing petroleum use and greenhouse gases, vehicles must become dramatically more efficient, regardless of how they are powered,” said Douglas M. Chapin, principal of MPR Associates, and chair of the committee that wrote the report.
“In addition, alternative fuels to petroleum must be readily available, cost-effective and produced with low emissions of greenhouse gases. Such a transition will be costly and require several decades. The committee’s model calculations, while exploratory and highly uncertain, indicate that the benefits of making the transition with energy cost savings, improved vehicle technologies, and reductions in petroleum use and greenhouse gas emissions, exceed the additional costs of the transition over and above what the market is willing to do voluntarily.”
NRC notes that improving the efficiency of conventional vehicles is “up to a point” the most economical and easiest-to-implement approach to saving fuel and lowering emissions. A process that is now well underway in the globally transportation industry due market forces as much as increasing stringent regulations and lavish taxpayer subsidies. (Read AutoInformed on President Obama Calls for $2 Billion Energy Security Trust Using Fossil Fuel Development Taxes to Wean U.S. from Oil and Gas)
Improved efficiency alone will not meet the 2050 goals, however. The average fuel economy of vehicles on the road would have to exceed 180 mpg, which, the report says, is extremely unlikely with current technologies.
Therefore, the study committee also considered other alternatives for vehicles and fuels, including:
- hybrid electric vehicles, such as the Toyota Prius
- plug-in hybrid electric vehicles, such as the Chevrolet Volt
- battery electric vehicles, such as the Nissan Leaf
- hydrogen fuel cell electric vehicles, such as the Mercedes F-Cell, scheduled around 2014
- compressed natural gas vehicles, such as the Honda Civic Natural Gas
All these vehicles above and their ilk comprise about 3.5% of the light vehicle sales in the U.S. currently, and that’s after more than a decade of Toyota Prius sales. The NRC acknowledges the obvious problem: Even though driving costs per mile are lower, especially for vehicles powered by natural gas or electricity, the high initial purchase cost is a significant barrier to widespread consumer acceptance.
And therein lays the problem – all these are and will continue to be several thousand dollars more expensive than today’s conventional vehicles for a long time.
The report identified several scenarios that could meet the more demanding 2050 greenhouse gas goal. Each combines highly efficient vehicles with at least one of three alternative power sources — biofuel, electricity, or hydrogen. (Natural gas vehicles were considered, but their greenhouse gas emissions are too high for the 2050 goal.) However, if the costs of these vehicles can be reduced and appropriate refueling infrastructure created, they have great potential for reducing petroleum consumption.
While corn-grain ethanol and biodiesel are the only biofuels to have been produced in commercial quantities in the U.S. to date, the study committee found much greater potential in biofuels made from lignocellulosic biomass – which includes crop residues like wheat straw, switchgrass, whole trees, and wood waste. This “drop-in” fuel is designed to be a direct replacement for gasoline and could lead to large reductions in both petroleum use and greenhouse gas emissions; it can also be introduced without major changes in fuel delivery infrastructure or vehicles. The report finds that sufficient lignocellulosic biomass could be produced by 2050 to meet the goal of an 80 % reduction in petroleum use when combined with highly efficient vehicles.
Vehicles powered by electricity will not emit any greenhouse gases, but the production of electricity and the additional load on the electric power grid are factors that must be considered. To the extent that fossil resources are used to generate electricity, the report says that the successful implementation of carbon capture and storage will be essential. These vehicles also rely on batteries, which are projected to drop steeply in price. However, the report says that limited range and long recharge times are likely to limit the use of all-electric vehicles mainly to local driving. Advanced battery technologies under development “all face serious technical challenges.”
When hydrogen is used as a fuel cell in electric vehicles, the only vehicle emission is water. However, varying amounts of greenhouse gases are emitted during hydrogen production, and the low-greenhouse gas methods of making hydrogen are more expensive and will need further development to become competitive. Hydrogen fuel cell vehicles could become less costly than the advanced internal combustion engine vehicles of 2050. Fuel cell vehicles are not subject to the limitations of battery vehicles, but developing a hydrogen infrastructure in concert with a growing number of fuel cell vehicles will be difficult and expensive, the report says.
