What is IGCC? Are IGCC Plants Practical?
Comment:
Dr. Feld,
TXU is using the same arguments against considering the cleaner IGCC technology that have been used by all utilities who are hell-bent on getting their conventional coal plants built before they have to face up to tightening air quality regulations that may include limits on CO2 emissions.
The main claims are that IGCC is not reliable and that it costs much more than coventional coal.
We find that the boiler manufacturers, who are enjoying a heyday these days, are providing a lot of the fodder that feeds such arguments. This is quite understandable, as IGCC would cut into their market just when the world is turning back to coal, and large coal-fired steam power plants to meet the growing need for energy.
Regarding the reliability issue, I find it a travesty that those who reject IGCC as unproven and unreliable still refuse to look beyond the US borders for their data. There are several commercial IGCC projects operating in Europe that are exhibiting plant availability levels well above the US national average for conventional coal plants.
Granted, some of these plants are using refinery wastes, such as asphalt, but the difference between using coal and these feedstocks is not that significant from a reliability standpoint. After all, proponents of PC plants will tell you that coal preparation systems are very reliable.
Also, if one looks into the data, including that from the US plants, one will see that most of the past problems with IGCC plants were due to the turbine equipment and not with the gasification system.
Both US plants (Tampa and Wabash) used early versions of the same model gas turbine that had many reliabiiity issues all over the world – not just in the two IGCC plants.
In Europe, an IGCC plant in Spain used another advanced-design gas turbine that also was the cause of most of the plant outage time.
Meanwhile, there are three or four plants in Italy, and one in the Netherlands, that used a more proven gas turbine design and were able to reach very acceptable availability levels within two or three years of operation.
A new IGCC plant in Japan has apparently gotten over its initial “teething problems” in only one year, and is operating quite satisfactorily.
With this experience behind them, there are European and Japanese suppliers, as well as ones in the US, who would supply an IGCC plant, and who would apply lessons learned from these earlier plants to make new ones even better.
In addition, the construction schedule for an IGCC plant should not be any longer than that for a modern PC plant. So it is not clear that IGCC technolgy would have a problem with meeting the real rate of load growth being experienced on the TXU system.
If an IGCC plant can enjoy the same “fast track” permiting process as being allowed for the proposed PC plants, there is no reason why the first plant couldn’t be online in 2011.
As for the other principal argument used against IGCC, that is, its higher cost, the issue today is that costs of large construction projects are escalating so steeply that it seems to be anyone’s guess what these plants will really cost. In other words, if someone claims that IGCC will cost, say, 20% more than PC plants, that is well within the uncertainty seen in current construction estimating.
Besides, we have been seeing some estimates for new PC plants coming in higher than most IGCC plant cost estimates, and they continue to climb.
In this regards, there was a study completed recently by the Electric Power Research Institute (EPRI) that was sponsored by CPS of San Antonio. That study did find IGCC plants to result in higher cost of electricity, but when one looks into its details, we found some questionable underlying design assumptions, as specified by CPS, that were the cause of most of the cost difference.
If EPRI were to do the same study over again, restating these assumptions to put IGCC on a more level playing field, we think that the results would be quite different.
Unfortunately, in the case of TXU, there was no parallel plant cost study performed in order to obtain a fair comparison of the two technologies. In the case of CPS, the study was done post facto, so quite naturally it could be expected to support the decision that was already made to go with conventional coal burning technology.
I’d fear that any similar study done by TXU, perhaps as might be ordered by the courts now looking into their plans for a new fleet of PC plants, would suffer from the same problem.
Apparently there is a third problem with IGCC that is raised by TXU, that being the claim that there are no suppliers who would guarantee an IGCC plant using low rank coals.
I’ve attended several conferences where the gasifier suppliers all say that they have the ability to use such coals in their gasification process – perhaps at some loss of efficiency and economy – as is the case of a PC plant as well. Granted that the case for IGCC is hurt somewhat with the use of poorer coals, but it is not so much for technical reasons as for economic ones.
TXU should be reminded that the demonstration plant that operated for a number of years during the late ’80s and early ’90s at the Dow Chemical facility in Plaqumemine LA operated on a wide range of coals, and mostly on sub-bituminous. The same gasification process is now operating commercially at the Wabash plant in Indiana and is being offered by ConocoPhillips (Houston) who purchased the technology a few years ago.
At the Wabash plant, the gasifier is co-firing coal with petroleum coke, which enhances the performance of the process and greatly improves the economics.
I hope that this information is helpful to you and to those who are urging the use of IGCC instead of perpetuating the use of PC technology which, as you have shown, promises to leave a long legacy of much higher impact on the air quality of central Texas, and on the health of your citizens.
Harry Jaeger
Gasification Editor
Gas Turbine World Magazine