Patzek: CTL coal-to-liquids from FT Synthesis is NOT likely to happen

CTL Mordor

This is a liquid fuel crisis – diesel to be exact – to keep tractors, trucks, trains, and ships moving. There’s not enough coal or water to make even a small percent of the FT-CTL diesel fuel we need from coal in Montana or Wyoming, and would turn these beautiful states into Mordor (in Tolkien’s trilogy “Lord of the Rings”).   Alice Friedemann at energyskeptic.com

Patzek, T. W. et al. Sep 2009. Potential for Coal-to-Liquids Conversion in the United States—Fischer–Tropsch Synthesis. Natural Resources Research, Vol. 18, No. 3

America has the world’s largest coal reserves, and the best spot to locate a coal-to-liquids (CTL) plant would be in Montana near one of the largest coal deposits. CTL is seen as a way to replace depleting petroleum reserves, but there are several major drawbacks:

  1. The Fischer-Tropsch (FT) process is only half as efficient as refining crude oil
  2. The resulting CO2 emissions are 20 times (2000%) higher
  3. An enormous amount of water is needed: 1000 kg of coal needs 1000 kg of water
  4. You’d need to use over 40% of the FT fuel energy to sequester the CO2
  5. CTL is a poor use for coal as long as natural gas is cheaper for generating electricity
  6. FT plants and the surrounding mine are very expensive to build
  7. converting petroleum to diesel fuel is 88% energy-efficient, but less than 50% efficient in the FT process (which produces a high-wax crude oil, not diesel fuel)

Only South Africa uses the FT process to make diesel and gasoline from 45 million tons of coal every year. This led to serious environmental problems:

  1. Enormous amounts of land are strip mined and covered with up to 50 million tons of mining waste per year, waste that’s high in sulfur (1-7.8%) and ash (24-63%).
  2. When the waste is burned, the Eastern Transvaal Highveld is doused in acid rain
  3. These plants need 5 barrels of water per barrel of FT oil produced

A small plant making 22,000 BPD of FT fuel would use 20% of the current coal production in Montana. A 300,000 plant large enough to supply the military would need twice as much Montana coal as is being mined now, three times as much Montana water as mines are now using,

The three larger plant designs extend into the realm of surrealism. For example, the 300,000 BPD plant, sufficient to supply most of the U.S. military needs, would consume twice the current coal production in Montana, thrice the current water use by Montana mines, and each year would produce 11 million toxic tons of ash with arsenic, mercury, sulfur, uranium thorium, among other things. Or as Tad Patzek puts it “If Montanans wish to destroy their beautiful state, then large FT plants offer an almost certain fulfilment of this wish….Stored coal ash slurries eventually threaten water supplies, human health, and local ecosystems.”

Electric power generation is the dominant use of coal in the United States, accounting for 92.3% of U.S. coal usage in 2006. Other industrial use accounted for 5.3% and coke accounted for only 2.1% of U.S. coal consumption in 2006.

It’s not clear that we can find enough coal for both CTL and coal generated electricity. Although natural gas plants have been increasing in number because of the temporary fracking boom, and the need to balance the wind load of intermittent power to keep the grid stable, there’s not enough natural gas to replace all coal plants.  Other load-balancing energy resources can’t step in for coal electric generation to free it up for CTL either: most geothermal is in non-coal-burning states with a max of 9,000 MW from known resources and perhaps another 33,000 MW left to be founde.  Nuclear power isn’t going to ramp up quickly for many reasons.

CONCLUSIONS

1. The large volumes of coal required for CTL suggest that the Powder River Basin of Wyoming and Montana is likely to be the coal source.

2. Although U.S. coal reserves are large, recent coal price increases suggest that there is no global coal surplus in the short term.

3. The Powder River coal, cheapest in the United States, would inevitably double or triple in price if there were a high-throughput railroad connection to the Pacific or Atlantic coast.

4. The energy efficiency of an optimal coal-based FT process that produces liquid fuels is 41%. This means that for every 1 unit of fuel energy out, one needs to put 2.4 units of coal energy in.

5. Because of the different energy contents of subbituminous coal and FT fuel, and a low energy efficiency of CTL conversion, roughly 800 kg of the average Powder River Basin coal will be needed to produce 1 barrel of the FT fuel.

6. Per unit energy in a liquid transportation fuel, carbon dioxide emissions from a CT plant are about 20 times higher than those from a petroleum refinery.

7. Subsurface disposal of carbon dioxide produced by the FT plants costs at least 40% of the thermal energy in FT fuel. If this disposal were deeper than assumed here, the current estimate might increase by a factor of up to 4.

8. Montana does not have the approximately 800 kg of clean water necessary to produce each barrel of FT fuel.

9. Natural gas can be compressed and used for transportation fuel with an efficiency of 98%. Therefore, the FT transportation fuel from coal is always uneconomic as long as natural gas competes with coal for power generation. This is true even if the gas-fired plants are more efficient combined cycle designs and the coal plants are conventional.

10. Judging by the recent financing of corn ethanol refineries, the astronomical construction costs of coal-based FT plants might be borne by the U. S. taxpayers through a new subsidy program.

11. The massive societal costs of the subsidies required to render CTL ‘‘economical,’’ and the environmental costs of fuel production would be borne by all Americans and the planet at large, but especially by the people of Montana and the surrounding states, including Canada

 

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2 Responses to Patzek: CTL coal-to-liquids from FT Synthesis is NOT likely to happen

  1. Sheila Chambers says:

    How much OIL is used to extract & transport that coal?

    I have seen images of the many huge machines used to remove mountain tops to gouge out that coal, the huge oil burning trucks used to transport that coal to the processing plant where massive amounts of water is used to clean the coal, then oil burning trains are used to transport that cleaned coal to where it’s to be used.
    After all that use of OIL just to get the coal to a usable state, then how much more energy is used in the FT process & what is the EROEI of the finished product?

  2. Spec9 says:

    Those are very good reasons NOT to build a CTL plant. However, it might still happen if we remain addicted to liquid fuels and ignore climate change. Rising oil prices could make it cost effective to do eventually. But for now, the focus will remain on tar sands, tight oil from shale formations, and deepwater oil. And those types of operations will expand to more foreign countries as the oil prices rise. So I don’t seem CTL happening anytime soon. But it could happen eventually.