Electric cars have been getting a lot of buzz lately, but a more immediately viable transportation fuel of the future could be liquid derived from coal. Scientists have devised a new way to transform coal into gas for your car using far less energy than the current process. The advance makes scaling up the environmentally unfriendly fuel more economical than greener alternatives.
If oil prices rise again, adoption of the new coal-to-liquid technology, reported this week in Science, could undercut adoption of electric vehicles or next-generation biofuels. And that’s bad news for the fight against climate change.
The new process could cut the energy cost of producing the fuel by 20 percent just by rejiggering the intermediate chemical steps, said co-author Ben Glasser of the University of the Witwatersrand in Johannesburg, South Africa. But coal-derived fuel could produce as much as twice as much CO2 as traditional petroleum fuels and at best will emit at least as much of the greenhouse gas.
“The bottom line is that there’s one fatal flaw in their proposed process from a climate protection standpoint,” Pushker Karecha of NASA’s Goddard Institute for Space Studies wrote in an e-mail to Wired.com. “It would allow liquid fuel CO2 emissions to continue increasing indefinitely.”
The race for alternative fuels kicked into high gear last year, with the price of oil reaching $150 a barrel before plummeting down below $40 this year. Still, though experts disagree on the specifics of timing, it’s clear that conventional oil sources will eventually run out. The list of contenders to replace oil is long and diverse. Alternative fuels could include next-gen ethanol, algal biofuel, hydrogen and natural gas, or cars could go largely electric.
But the problem with all the new fuels is that they have to scale up — and that’s harder than it sounds. Plus, many fear that biofuels could cause massive, negative land-use changes.
The process of cooking coal into liquid fuel, on the other hand, has already proven itself on a massive scale. Take coal, add some water, cook it, and you’ve got a liquid fuel for your car. The hydrogen in the water bonds to the carbon and voila: hydrocarbons, such as octane. It’s the very fact that coal-to-liquids could work that make them such a scary idea for people devoted to fighting climate change.
The Nazis used the so-called Fisher-Tropsch process to provide up to half of their transportation fuel needs during World War II. Later, South Africa began a major coal-to-liquids program during the Apartheid era and now maintain the world’s largest CTL industry in the world. The country’s factories produce 160,000 barrels of fuel a day, a little more than all the residents and businesses in Utah use each day.
The traditional process uses carbon monoxide, carbon dioxide, and hydrogen as the ingredients in the molecular soup that gets turned into hydrocarbons. The Science process uses just CO2 and hydrogen.
Glasser’s new production method allows them to set a lower limit on the amount of energy that would be needed to transform solid coal into fuel. The very best possible CTL process would require 350 megawatts of input to make 80,000 gallons of fuel; the current process uses more than 1,000 megawatts.
Even with the small efficiency gains, a large, domestic, carbon-intensive source of transportation fuel would throw a wrench into many plans to reduce emissions from vehicles.
“What they’re proposing is simply not allowable if we want to avoid the perils of unconstrained anthropogenic climate change,” Karecha said.
But Ben Glasser defended the work as a good intermediate step that would help keep energy flowing even as oil reservoirs dwindle. And he said that the lessons his team learns could be applied to waste streams or renewable sources.
“The long-term solution has to be solar, wind, renewable, but in the meantime I know as a chemical engineer that the easiest thing is to improve on what you’re already doing,” Glasser said. “The hope is that what we learn with coal-to-liquids, we can take one step further and start using municipal waste or cooking oil, for example, as the carbon source.”
In this case, though, green-tech advocates say that improving a fossil-fuel technology could slow the adoption of other, more sustainable transportation options.
“We are simply running out of time to avoid catastrophic warming, and we no longer have the luxury of grossly misallocating capital and fuels to expensive boondoggles like coal-to-liquid,” Joe Romm, a senior fellow at the Center for American Progress, told the House Science and Technology Subcommittee on Energy and Environment last year.
The conflict over which energy source replaces oil as it becomes more scarce is likely to be a massively divisive political topic. The winning technology could play a huge role in determining whether the American economy can decarbonize before the effects of catastrophic climate change occur.