Hydrogen Vehicles Coming Soon? Two Million Could Be On Roads By 2020

Rear view of a hydrogen fuel cell car. By 2023, the total cost of fuel cell vehicles, including the cost of hydrogen fuel over a vehicle's lifetime, could become competitive with conventional vehicles.

A transition to hydrogen vehicles could greatly reduce U.S. oil dependence and carbon dioxide emissions, says a new congressionally mandated report from the National Research Council, but making hydrogen vehicles competitive in the automotive market will not be easy. While the development of fuel cell and hydrogen production technology over the past several years has been impressive, challenges remain.

Vehicle costs are high, and the U.S. currently lacks the infrastructure to produce and widely distribute hydrogen to consumers. These obstacles could be overcome, however, with continued support for research and development and firm commitments from the automotive industry and the federal government, concluded the committee that wrote the report.

Light-duty vehicles, such as cars, SUVs, and pickup trucks, are responsible for 44 percent of the oil used in the United States and over 20 percent of the carbon dioxide emitted. Concerns over climate change, oil imports, and recent spikes in gasoline prices have spurred interest in the development of alternative fuels. In 2003, President Bush announced a $1.2 billion initiative to encourage development of hydrogen production technology and fuel cell vehicles, which are powered through a chemical reaction between hydrogen and oxygen and emit only water and heat as exhaust.

The committee estimated the maximum number of hydrogen vehicles that could be on the road in the coming decades, assuming that practical technical goals are met, that consumers want hydrogen cars, and that government policies are in place to help drive the transition from oil to hydrogen fuel. The findings therefore represent potential best-case scenarios rather than predictions.

According to the committee, it will take many years before hydrogen vehicles will significantly penetrate the light-duty fleet, even though technological developments have been progressing rapidly. Production of hydrogen vehicles could increase significantly by 2015. At this stage, their cost -- although dropping rapidly -- would still need to be heavily subsidized for consumers.

The maximum practicable number of hydrogen vehicles that could be on the road by 2020 is 2 million, says the report. By 2023, the total cost of fuel cell vehicles, including the cost of hydrogen fuel over a vehicle's lifetime, could become competitive with conventional vehicles. At that point, the number of hydrogen vehicles on the road could grow rapidly, to nearly 60 million in 2035 and 200 million by 2050.

The committee also calculated the investments, both public and private, that would be needed to make a complete transition from oil to hydrogen fuel. These costs include research and development, vehicle deployment, and establishing infrastructure. According to the committee, government support via strong policy initiatives as well as funding would be needed until at least 2023. The cost to the government would be about $55 billion between 2008 and 2023; private industry would be expected to invest $145 billion over that same time period. To put these numbers into perspective, the government subsidy for ethanol fuel could grow to $15 billion per year by 2020.

The shift toward hydrogen fuel would not have a large impact on oil usage or greenhouse gas emissions until hydrogen vehicles make up a significant portion of the market. If hydrogen vehicles eventually took over the market, there would be great decreases in both, although the overall effect on greenhouse gas emissions would depend upon how the hydrogen fuel was produced. The committee compared these reductions with those that might be achieved by either improving the fuel efficiency of conventional vehicles or by converting to biofuels. Because they can be implemented more rapidly, both of these options could produce reductions in oil use and emissions faster than hydrogen, but after about 2040, hydrogen would become more effective.

The greatest possible reductions would occur if biofuels, fuel-efficient conventional vehicles, and hydrogen vehicles are all pursued simultaneously, rather than seen as competitors. This "portfolio approach," if accompanied by government policies driving a transition toward reduced oil use and low-carbon fuels, could reduce greenhouse gas emissions from cars and trucks to less than 20 percent of current levels and could nearly eliminate oil demand for these vehicles by 2050, the committee said.

The study was sponsored by the U.S. Department of Energy. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council are private, nonprofit institutions that provide science, technology, and health policy advice under a congressional charter. The National Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering.

Nature-Nurture Gene Link Sheds New Light On Autism

Researchers believe autism spectrum disorders are tied to brain changes that occur during critical periods of development.

Neuroscientists at MIT's Picower Institute for Learning and Memory found that a previously unsuspected set of genes links nature and nurture during a crucial period of brain development.

The results, reported in the July 8 issue of the Proceedings of the National Academy of Sciences (PNAS), could lead to treatments for autism and other disorders thought to be tied to brain changes that occur when the developing brain is very susceptible to inputs from the outside world. Nature--in the form of genes--and nurture--in the form of environmental influences--are fundamentally intertwined during this period.

"Our work points to how a disorder can be genetic and yet be dependent on the environment," said co-author Mriganka Sur, Sherman Fairchild Professor of Neuroscience at the Picower Institute and chair of MIT's brain and cognitive sciences department. "Many genes require activity to be expressed and make their assigned proteins. They alter their expression when activity is altered. Thus, we reveal an important mechanism of brain development that should open up a window into the mechanisms and treatment of brain disorders such as autism."

In the brain, some genes are only expressed, or turned on, in response to stimulus from the outside world. Like a panel of switches that turn lights on and off, genes that don't receive electricity don't "turn on" and express their particular proteins.

Sur and colleagues found a set of novel genes--including a calcium sensor called cardiac Troponin C, or cTropC--particularly sensitive to a critical period of development. The lack of proteins from these genes during a key phase of development could be one of the culprits in developing autism.

Researchers have long investigated the molecular mechanisms involved in monocular deprivation--when one eye is deprived of sight during a critical period of brain development, that eye becomes permanently blind, even after it is uncovered. This phenomenon is considered an important model for brain development because synapses for the covered eye--deprived of environmental stimulus, or what Sur calls "nurture"--shrivel up or get reassigned to other uses.

Sur and his colleagues looked at which genes are expressed, and which are not, when this phenomenon occurs. They hoped to pin down the correlation between nature--meaning the genes--and the external environment, or nurture. By identifying which genes are particularly apt to switch their expression patterns in response to "nurture," the researchers potentially narrowed down the ones that may be implicated in developmental disorders.

Researchers believe autism spectrum disorders are tied to brain changes that occur during critical periods of development. Different but overlapping critical periods are thought to exist for various cognitive functions affected in autism, such as language and social behaviors.

"Autism is a strongly genetic disorder: genes set up risk factors but by themselves simply make proteins," Sur said. "Genes work together with other influences. In the case of autism, these influences are unknown but could be molecules made by other genes or chemicals from the environment."

If scientists understood how genes changed in response to environmental influences during this crucial developmental period, they might be able to one day prevent or reverse the changes.

In addition to Sur, authors are Alvin W. Lyckman, a former MIT postdoctoral associate now at Tufts University; MIT brain and cognitive sciences graduate students Sam H. Horng and Cortina L. McCurry; Picower Institute postdoctoral fellows Daniela Tropea and Audra Van Wart and colleagues from other institutions.