Democrats in Congress continue to push forward with proposals to heavily subsidize plants for converting coal to liquid fuel, which we previously noted is the worst idea in the universe. The surprisingly varied response to our earlier post demonstrated that we didn’t do enough work to show why coal-to-liquid technology is such a misguided notion. So here it is again, with a bit more analytical heft.
One fact that sometimes goes unappreciated is that it takes energy to make energy. Or rather, it takes energy to deliver energy in a usable form. When you pump gas into your tank, you’re purchasing a consumer product that sits at the end of a long supply chain. In the case of gasoline, that supply chain begins at an oil well; traverses oceans and continents via tanker and pipeline; routes through refineries and distribution centers; and finally fans out to gas stations all across the country.
Every step in that process requires energy for processing and transportation. The amount of energy varies dramatically depending on the nature of the product. There’s a technical term for this: energy returned on energy invested, or EROEI. Which is just a fancy way of analyzing the energy content of a fuel based not just on what you get out of it, but also on what you put into it.
EROEI explains my offhand crack about corn ethanol in the previous post. The process of turning corn into a substance that will fit in a gas tank requires almost as much energy as the corn ethanol itself provides. That conversion process itself is powered by fossil fuels, which means that corn ethanol isn’t much better than gasoline from a carbon perspective.
Now let’s consider coal to liquid. A lot of energy is required to turn coal into diesel fuel. Consider, again, this graphic from the New York Times:
You can see that coal-to-liquid technology releases more than twice as much CO2 as petroleum on a comparable basis. And now, roughly speaking, you know why: you have to spend a lot of energy powering the conversion process to diesel.
Fair enough, but coal is domestically produced, so isn’t coal-to-liquid a step toward energy independence? Actually, it’s a step backwards. If we want to use coal to power our cars, there is a much more straightforward way: turn the coal into electricity — which we’re already pretty good at — and use it to power plug-in hybrids. Because of the higher EROEI of using coal to create electricity, we could displace a far larger amount of imported oil this way at a comparable level of carbon emissions.
So: bad for the environment, bad for energy independence, and bad economically. The only thing coal-to-liquid technology is good for is channeling money to the coal industry. Which is why these bills are now racing forward.