Diesel Fuel From Coal Is Not Energy Efficient

By James Donahue

December 2005

As the world’s demand for petroleum grows and the realization that we have already reached peak production of raw crude, the hype these days is: not to worry . . . we have the technology to extract all the liquid fuel we need from coal.

In fact, companies like Syntroleum and Rentech Development are among a number of firms that are already refining something known as the Fischer-Tropsch process for turning coal into diesel fuel.

The Fischer-Tropsch process was developed in Germany in the 1920s as a way of creating synthetic diesel to keep its planes in the sky during World War II.

But that was wartime. This is now. And for the contemporary world that is struggling to operate millions of automobiles, commercial trucks, trains, ships and aircraft on fuel from petroleum, the cost of running the show on synthetic fuel from coal is not only unrealistic, but non-efficient.

While the United States alone has an estimated coal reserve of 500 billion tons that could be converted into more fuel that exists in all of the world’s petroleum reserves, the picture is not that rosy.

That is because the Fischer-Tropsch process calls for “super-heating” the coal to release a gas, which then is cooled and turned into a liquid. That liquid is then processed into a diesel fuel.

Where do you think the energy will come from for super heating the coal? And where will it come from to operate the processing plant that manufactures the final product?

This writer is not a physicist, or a chemist, or a mathematics whiz. But he sees a fly in this ointment all the same. Just like the process for producing hydrogen, another touted fuel alternative, the Fischer-Tropsch concept appears not to be fuel efficient.

In other words, it takes more energy to make the fuel, than can be gained from the finished product. Thus we are only fooling ourselves if we think we can find a cheap fuel in coal for operating the world’s machines.

So far, the best idea for creating a synthetic diesel fuel has emerged from Brazil where government supported processing plants are starting to convert natural oils from soy beans, sunflower seeds and certain tropical plants into a synthetic biodiesel. That might work if farmers can spare enough land after meeting the growing demand for world food production.

The final problem with all of these alternative fuel ideas, however, is that they all continue to spew greenhouse gas emissions. The biodiesel produced in Brazil has been shown to burn dramatically cleaner, but it still has emissions.