for National Geographic News
What would happen if all the vehicles in the U.S. swapped gas tanks for hydrogen fuel cells?
A team at Stanford University has studied the potential effects on pollution if all U.S. vehicles converted to hydrogen fuel-cell vehicles (HFCVs).
The switch could prevent 3,700 to 6,400 deaths attributable to pollution in the U.S. each year, the team reports.
The team's complete findings are reported in the current issue of Science.
"This technology could potentially make the quality of life much better for hundreds of millions of people around the world," said Mark Jacobson, an engineer at Stanford University in Palo Alto, California. "Gas and diesel produce photochemical smog. These pollutants have many adverse health effects like cardiovascular disease, respiratory illness, and asthma."
Hydrogen, meanwhile, can power a fuel-cell vehicle that emits very little pollution, Jacobson notedessentially only a bit of water vapor.
Estimates about the climate-altering greenhouse-gas emissions that HFCVs might produce, however, vary widely, depending on how the hydrogen fuel itself is manufactured.
For their study, Jacobson and colleagues assessed the environmental effects of three different hydrogen production methods: making it from natural gas, with wind power, and from coal.
The team reported that using coal to make hydrogen would actually produce more greenhouse gases than if all U.S. drivers switched to gas/electric hybrid vehicles like those currently on the market.
The study found that other methods promised environmental benefits of varying degree, with wind power being the cleanest.
Currently, nearly all hydrogen produced for industrial uses, and for existing HFCVs, is made from natural gas.
"We concluded that if you generate hydrogen from wind or natural gas you get a clear benefit over gas/electric hybrid vehicles, though hybrids would also represent an improvement over the current fleet," Jacobson said.
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