Making coal green
To address global warming, we're going to do something that may surprise the save-the-planet camp: burn more fossil fuel less efficiently. Big oil will prosper.
It's official: Global warming is a Republican party issue, too, now that the Bush Administration has acknowledged its gravity. So something will be done. But what? To address global warming, we're going to do something that may surprise many in the save-the-planet camp: burn more fossil fuel less efficiently. Big oil will prosper. So will Saudi Arabia.
Fossil fuels--hydrocarbons--are part hydrogen, part carbon. Both elements burn nicely. Your charcoal barbecue burns pure carbon; the Space Shuttle's main engine burns pure hydrogen. The carbon, which becomes carbon dioxide when you burn it, is what the climate models link to global warming.
Natural gas contains relatively more hydrogen and less carbon; that's why greens like it more than other fossil fuels. Over half of the heat from a methane-gas flame comes from the hydrogen. About 80% of the heat in coal comes from the carbon. Oil is in the middle.
One way to burn hydrocarbons without raising carbon dioxide concentrations in the atmosphere is to burn first, then suck the carbon back out of the air--by growing new trees, for example, or by seeding the oceans with iron to promote massive new growth of algae. If things go right, the new green plants will get buried, and in the fullness of geological time, turn into new coal--call it recycling. This is the cheapest approach and the greenest, too, but it doesn't curb energy consumption. And, if the truth be told, many environmental activists are as determined to curb energy consumption as such as they are to curb carbon emissions.
A second option is to strip the carbon from the fuel before you burn it. Most fuel cells depend on "reformers" that do just that. Most current reformers dump the stripped-out carbon into the air as carbon dioxide, but other processes leave the carbon behind as a solid residue. That takes care of carbon emissions all right--roughly speaking, such a fuel cell starts with methane, extracts the hydrogen and then returns coal to the ground. But this also costs about 50% of the heating value of the original gaseous fuel.
We might eventually displace some coal when we find an economical way to liquefy natural gas; making it easier to transport. But it won't be a lot of coal, and the carbon reductions would be modest in any event. Every other alternative on the low-carbon diet plan entails a significant energy overhead, too. Scrubbing huge amounts of carbon dioxide out of smokestacks and tailpipes isn't easy and can't be done without sharply reducing efficiency. We already pay significant efficiency overhead for the scrubbers that remove comparatively tiny amounts of sulfur dioxide from coal plant smokestacks and for the catalytic converters that remove comparatively tiny amounts of nitrogen oxide pollutants from tailpipes.
The long-term hope for many greens is that we can get beyond hydrocarbons and burn just the first half of those compound fuels, the hydrogen. Hydrogen is abundant, they remind us; it's part of water. But water is what you end up with after you burn the hydrogen in the hydrocarbon-steam goes out the tailpipe and up the smokestack, alongside the carbon dioxide.
To turn water back into hydrogen fuel again, you have to unburn it--you have to pump energy back into the water, usually in the form of electricity. The greens know this but hope that the electricity will be solar. Perhaps someday, but anyone who does the numbers knows that it won't be anytime soon-solar isn't close to cost-competitive yet, and the panels require ridiculous amounts of real estate. Coal-fired or gas-fired electricity won't do either--that would defeat the whole carbon-reduction objective. Nuclear power plants could be used, but if there's one element that most greens hate even more than carbon, it's uranium.
So it is more or less inevitable that we will indeed burn hydrogen, the most pristine of all fuels, just as they hope. And we will accept that the only readily available supplies of hydrogen in unburnt form are in gas, oil and coal. The policy will be to burn more fossil fuel, less efficiently--to extract a lot less heat out of the same amount of fuel. Even as manufacturers struggle to design new car engines that go farther on the same amount of heat. We will raise efficiency at every stage of the energy pipeline except at the source, where we will reduce it, drastically, far more than we can raise it in any of the tiers above. This may perhaps save the ice caps. It certainly won't ruin the oil companies.
This piece originally appeared in Forbes
This piece originally appeared in Forbes