Zero Emissions Gasoline Production - Part II

My previous piece dealt with a claimed breakthrough in liquid fuel production occurring in the context of coal gasification, the prevailing form of coal-to-liquids conversion technology. This second installment focuses on the details of this new variant.

In Situ without Fire

All previous attempts to produce syngas underground have involved igniting the coal in place. The process is wasteful in that it cannot be precisely controlled as is the case with a surface gasifier, but inasmuch as it dispenses with an external reactor, it eliminates a major cost item. Proponents cite vastly cheaper capital costs on this account, but it must be said that the few governments reports on the process tell a different tale. Capital costs are still likely to be in the hundreds of millions of dollars for a small commercial plant, which is less than for a full blown surface processing operation but hardly inexpensive.

The IEP new process eschews conventional combustion methods and substitutes what the company calls a geothermic fuel cell. The company claims significant cost and emissions advantages for this technology.

The term geothermic refers to the fact that the fuel cell in this application is used to heat the coal to a temperature where gasification occurs. The fuel cell itself is of the solid oxide type.

Solid oxide fuel cells are high temperature designs with solid ceramic electrolytes. Siemens-Westinghouse is the major manufacture of this type, though a multitude of other companies have attempted to compete against them. The IEP fuel cell is not a Siemens product, however, but is instead a proprietary design developed by Battelle, a major American scientific research organization.

Most solid oxide cells run on either natural gas or syngas, the latter being a combination of hydrogen and carbon monoxide. The IEP unit only utilizes carbon monoxide, which, while readily obtainable from the coal itself, is a fairly low energy fuel. The hydrogen produced from coal is presumably utilized for the production of hydrogen rich syngas which will be converted in light and middles distillates.

Solid oxide fuel cells are highly efficient, exceeding 50% energy conversion rates in producing electricity from the chemical reaction and 80% efficiency if one factors in the heat they produce as well. As is the case with batteries they produce electrical energy through ionization processes rather than combustion and are not subject to the efficiency limitations of heat engines utilizing internal or external combustion. They do however produce carbon dioxide as a waste product—nearly 100% CO2 when pure carbon monoxide is used as a fuel. But compared to combustors they produce less CO2 per a given value of electrical or thermal energy generated.

IEP claims an 80% reduction in CO2 emissions, a figure which I find questionable. Solid oxide fuel cells are certainly more energy efficient than combustors but not several times as efficient. Still, a real reduction should be realized, and, moreover, the exhaust should be a very pure CO2 stream if only carbon monoxide is used as fuel.

How Much?

IEP has developed fairly detailed cost estimates for a 10,000 barrel per day facility using their technology and cites a total plant capital cost of $656 million, a figure that is roughly comparable with estimates for conventional in situ production facilities of similar capacity. The big question concerns the cost of the fuel cells since they are not production items at present.

Polymer electrolyte membrane (PEM) fuel cells, the type favored for automotive applications and the most commonly used today are priced in the thousands of dollars per kilowatt. A PEM fuel cell designed for an automobile will cost several hundred thousand dollars which explains why the technology has never been adopted by the car manufacturers. Many attempts have been made to reduce manufacturing costs but to little avail.

Solid oxide fuels cells are essentially pre-commercial today, and for that reason cost projections are somewhat conjectural. They would appear to be less expensive to manufacture than PEM cells because they utilize much cheaper materials and do not require micro-fabrication, but that they actually will be cannot be stated with certainty. To date, fuel cells of practically all sorts have been inordinately expensive per power output, a fact that has limited their acceptance in the marketplace and confined them to a few niche applications. Those niche markets have been small and have not supported sales volumes sufficient to provide manufactures with real experience in mass production.

The Department of Energy has devoted considerable energy to developing cost estimates, and in its latest reporting on the subject has cited costs per kilowatt of $726, significantly less than for PEM types. The DOE projects costs declining to $400 per kilowatt in the midterm, and suggests that solid oxide cells might eventually be cost competitive with heat engines, though with small mass produced gasoline engines going for around $20 per kilowatt on the manufacturing level, we're not sure when parity might be achieved.

At any rate the cost of geothermic fuel cells for a 50,000 barrel per day facility would be over $200 million at present manufacturing prices and a bit over $100 million with projected price decreases.

The advantage of solid oxide fuel cells for sort of application envisioned by IEP is that they readily scale to large sizes, in fact most of manufacturers see them figuring in large scale stationary electrical generation.

I might mention that Lawrence Livermore National Laboratory performed some modeling work involving in situ retorting of oil shale using solid oxide fuel cells, and found the economics to be favorable. Interestingly, IEP has an oil shale program as well as the in situ coal-to-liquids project.

I still think in situ production using combustion is likely to be cheaper but then it is also likely to be dirtier and much more wasteful of the resource. The IEP technology is definitely a development to watch.