The history of alternative transportation fuels is a history of failure. It is a story of one fuel du jour after another—a frustrating cycle of media and political hype followed by disillusionment and abandonment.

The cycle is all too familiar, from synfuels in the late 1970s to methanol in the ’80s, and then electric vehicles, hydrogen, and ethanol. Only corn ethanol has survived in the United States, but it would be a stretch to call it a success, given its big carbon footprint and relatively high cost (subsidized at about $6 billion per year in the United States today). A new wave of electric vehicles are now at risk of entering the cycle again.

Replacing petroleum will be difficult and slow. Its hegemony creates huge barriers for new fuels, in terms of economics, legal liability, public skepticism, and media sensationalism. Our three best hopes—hydrogen, electricity, and biofuels—all face large challenges.

Hydrogen would require us to transform our fuel supply system. Electricity must overcome the shortcomings of batteries (see “Will Electric Vehicles Finally Succeed?”). Advanced biofuels need a lot of land and leave a large carbon footprint. However, no other green energy technologies will come into being easily or quickly. At least one of these three—and probably all—must eventually thrive if we are to change the kind of energy we use for transportation.

For plug-in hybrid and all-electric vehicles, I see two possible scenarios. The most likely, judging by failed fuels of the past and recent experiences with hybrid cars like the Prius, is slow investment. After 10 years in the U.S. marketplace—13 in Japan—hybrids have gained only 3 percent of the country’s market for new cars. Plug-in electric vehicles are more costly, require large-scale investment in recharging infrastructure, and are more alien to consumers. Absent any dramatic change to market conditions, can we really hope they will be more popular than hybrids?

A more optimistic scenario would require strong national standards for new vehicles, similar to regulations now being contemplated by California and the U.S. Environmental Protection Agency. The EPA already requires 40 percent reductions in fuel consumption and greenhouse-­gas emissions by 2016, and it is considering further mandatory decreases of up to 6 percent per year from 2017 to 2025. Automakers could meet such standards at first with better conventional engines and gas hybrids. But they would later be forced to invest in advanced plug-in technologies, to achieve the steep improvement needed to keep pace.

This optimistic scenario is supported by the existence of large federal and state subsidies for plug-in electric vehicles, and by a strengthening commitment to them in China. While battery technology will always be expensive, the right combination of strong policy, strong competition, and consumer enthusiasm could speed the adoption of these cars.

Dan Sperling is director of the Institute of Transportation Studies at the University of California, Davis, and author of the book Two Billion Cars.