What happens when we run out of oil and coal?

July 15, 2010

Many of the plans for addressing climate change rely on 20- to 50-year roadmaps of increased efficiency and use of renewable energy. But, as Nobel Laureate Robert Laughlin pointed out in his talk at the Lindau Meeting, we’re going to have to deal with alternative technologies on that time scale no matter what—many projections indicate we’re going to be out of oil within 60 years (usable coal will last a century and a half longer, give or take). So, even if you don’t think climate change is something to worry about, Laughlin suggested you might want to be thinking about the sorts of technologies we’d need to do without fossil fuels—and that, in turn, requires some thought about what existing technologies we’d want to bring forward.

Laughlin got his Nobel for providing a theoretical explanation for some odd behavior of bulk electrons, recognizing that they were acting as if they were a quantum fluid. Energy policy is only related in that the energy used to run cars and airplanes involves shuffling electrons around in chemical bonds, but it’s what he’s thinking about these days.

For many purposes, we shuffle the electrons by burning hydrocarbons, which are useful because they have a fantastic energy density. Batteries can provide electrons for a number of uses, like short-distance road transit, but they simply don’t have an energy:mass ratio that’s compatible with things like aircraft or long-distance travel, and Laughlin didn’t think they were likely to get there. Biofuels might be a partial replacement, but he was unwilling to make a bet on a technology that might ultimately compete with food supplies.

Hydrogen, when compressed, can have a decent energy density, but its high-pressure storage and explosive tendencies make it a very iffy choice for things like aircraft. Laughlin made an explicit comparison between the slow-burn of jet fuel, which has enabled some orderly evacuations of aircraft, to the explosive demise of the Hindenburg. In essence, he suggested, the best way to store hydrogen for use in transportation is as a hydrocarbon. And, give or take the errors in various sources, we’ve only got about 60 years of liquid hydrocarbons left—assuming we’re willing to accept the climate consequences of burning it all.

One alternative would be to find a way to do without some of the things we currently rely on hydrocarbons for. Laughlin seemed to be giving his talk with the assumption that the electric grid, if needed, could be transitioned to something else. But he (and most of his audience) was skeptical that we’d be willing to do without cars. He said that in conversations around the world in many different cultures, the universals tended to be worries about a person’s home, their children’s’ education, and getting a nicer car. He just doesn’t see people giving up on that sort of autonomous personal mobility, nor did he expect that electric vehicles being able to fully handle all the driving needed.

Airplanes are even worse, since there’s no way to substitute anything for the hydrocarbons that fuel them without giving up almost all of their carrying capacity. We may cut back on air travel if the price is high enough, but Laughlin doesn’t see their use ending entirely, in part because militaries will keep the technology afloat. (He also made a joke about a businessman calling home and informing his wife he’d be late for dinner, since he had to swim home from France.)

So, we’ll want liquid hydrocarbons, but we’ll inevitably run out. What happens then? Laughlin suggested that there’s a real risk of political instability as oil supplies run short and prices destabilize; he warned that the younger people in the audience were likely to be around to see that, and their children would be of the age where they’d be expected to manage the transition. But, ultimately, he expected we’d end up turning to another hydrocarbon, coal, and the use of the Fischer-Tropsch process to transform it into liquid fuel at the cost of some significant energy input.

That could buy us another 150 years or more, based on current coal reserves. But some of these reserves are unlikely to ever be harvested economically, and the environmental costs of coal tend to be far higher than those of oil, so the planet’s full supply of coal is unlikely to come into play. Once we used the accessible supplies up, Laughlin could only guess what might take place; feeding the Fischer-Tropsch infrastructure with algae grown in saltwater was one idea.

The point of his talk wasn’t so much to make accurate predictions of the precise trajectory of hydrocarbon reserves or to focus on a particular technological solution. Instead, Laughlin thinks that the arguments over climate change have become a distraction; the sorts of time periods involved for many solutions to it are only off by a few decades from when the energy economy would be undergoing radical changes anyway. If we could actually plan for the ultimate eventuality—the absence of hydrocarbons—instead of whether it should come about through legislation or combustion, we might be able to get somewhere.

What we should be getting, Laughlin implied, is the development of technologies that actually provide us with the sorts of services that we’re ultimately going to want, like long-distance car trips and airplane flights. Although it was never stated explicitly, the clear subtext of the whole discussion was that fixes that don’t give people what they want aren’t going to end up being fixes at all.

One thing that was less explicit (and, unfortunately, I forgot to ask Laughlin about this when I talked with him the next day) was the issue of pushing sustainable technology out before we actually need it. A heavy push for sustainable tech such as renewable fuels could help push back the deadlines on the end of the fossil fuels, and insulate society from some of the worst disruptions caused by short supplies and skyrocketing prices. The fact that an early push could help limit the impact of climate change would be an obvious bonus.

This post has been written by John Timmer on July 15, 2010 7:14 PM couresy of arstechnica.com.


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