Friday, January 12, 2007

Oil from Coal?

Energy independence is becoming the biggest energy issue in American politics. If it hasn't eclipsed climate change in importance, that's only because many see the two issues as strongly connected. Over the last three years, I have written a variety of postings pointing out just how big and challenging a goal energy independence is--not to take the wind out of the sails of those pushing for it, but to promote realistic expectations about how long it would take to achieve, even if we started right away. My analysis has typically focused on the complexities of replacing oil with biofuels, or on shifting our power generation to wind and solar power, to produce or displace the energy to fuel cars. Along the way, I've neglected another obvious choice for closing the oil import gap: converting coal into synthetic oil.

The recent tributes to President Ford brought back vivid memories of the energy crisis of the 1970s. How many times since then have we heard that America is the "Saudi Arabia of coal?" It's true enough. We produce 18% of the world's coal, and only China produces more (twice as much, in fact.) Our coal reserves are sufficient to sustain these production levels for another 236 years, based on current rates of recovery. In addition to this vast raw material, we have the technology to turn coal into synthetic gasoline and diesel fuel. It's not a cheap process, but it is proven.

Coal can be gasified to produce a synthesis gas (carbon monoxide and hydrogen,) which is reacted using a catalyst to create liquid hydrocarbons. The Germans used a version of this technology in World War II, as has South Africa since the Apartheid era. Other counties are working on it today. The biggest hurdle to doing that here was always economic, rather than technical; oil at its typical price of $25/barrel yielded gasoline at about $1.25/gallon at the pump, including tax, and coal-to-liquids (CTL) simply couldn't compete. At $50-60/barrel, though, cost isn't nearly as big an impediment, and were it not for our concern about climate change, or our growing appetite for coal in the power generation sector, because of the high price of natural gas, CTL would look like a slam-dunk energy independence pathway.

In fact, it still could be, if we had a cheap way to sequester all the CO2 produced as a byproduct of turning coal into liquid fuels. Synthetic gasoline or diesel produced from coal releases no more greenhouse gas when combusted than fuels derived from petroleum, and there's a pretty solid argument that advanced diesel engines running on ultra-clean CTL diesel offer nearly as big an efficiency improvement (and thus greenhouse gas reduction) as gasoline hybrids, for a lower up-front cost premium over conventional cars. Throw plug-in hybrids into the mix, and coal can contribute in two ways: providing the liquid fuel for the onboard engine and fueling the power generation behind the plug.

To many Americans that scenario might sound a lot more realistic and achievable than trying to ramp up biofuels and other renewable energy sources from their current very small base (3% of total US energy use.) The problem is that our current oil shortfall is roughly 13 million barrels per day, including imported petroleum products. Coincidentally, that figure is just a shade larger, on a BTU-equivalent basis, than the entire US output of coal. In other words, even if the CTL conversion were 100% efficient, which it isn't, this approach to energy independence would require us to double our current production of coal, with all of the environmental, land-use, and human consequences that would entail. In any case, it would take many years, and the price tag for the capital equipment involved would be at least a half Trillion dollars, just for the CTL side, ignoring the additional mining and transportation infrastructure required.

Now, I'm not suggesting that CTL or any other technology must be capable of replacing every drop of imported petroleum, before it could be considered a good candidate for improving our energy security. But if the only other energy source already operating at a similar scale to oil or natural gas--accounting for 23% of US energy consumption and half our net electricity generation--couldn't realistically fill the entire US oil supply gap anytime soon, then neither could any combination of renewables or other sources. If we're serious about reducing our reliance on imported oil, then not only should we invest aggressively in technologies like CTL, but we must also tackle our inefficiency and shore up our flagging domestic oil production. That means drilling in places we'd rather not drill, because they are scenic or sensitive. Unless we work on all three fronts simultaneously, the odds are that ten years from now we'll find ourselves at least as reliant on the Middle East as we are today, and wondering why energy independence remains as elusive as it was when Gerald Ford was President.

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