mong the clean coal technologies, IGCC (integrated gasification combined cycle) has been much talked about for many years. There have been several occasions when its proponents have declared that the technology’s time had come, that it was on the verge of a breakthrough and poised for substantial growth. But although the first coal-fuelled IGCC plant (Steag’s Lunen facility in Germany) has been operating since 1972 there is still only a handful of such plants operating around the world.
Once again we are seeing a flurry of interest in IGCC power plants as a clean coal option. But will it amount to anything? Will any new plants actually get built?
We have been here before of course. Take the UK, for example. Only four or five years ago the de facto moratorium on new gas-fired power plants engendered talk of a new dawn for IGCC. But nothing came of it, with low electricity prices proving fatal to many of these ideas. Progressive Energy is still pursuing its plans for the Drym IGCC, and is exploring further projects in the north east of England. The Hatfield IGCC project has Section 36 approval, but has not been helped by the Hatfield colliery and the project developer Coalpower (owner of the colliery) going into receivership.
Nevertheless, a number of drivers now seem to be coming together that shift the balance in favour of IGCC, spawning a new outbreak of cautious optimism in the coal gasification community.
A key factor is of course the current trend towards higher natural gas prices, and the volatility of those prices, compared with the relative long term stability of coal. But in addition worries about overdependence on gas and the problems of supply security have risen to somewhere near the top of the agenda for many power companies. Indeed, according to the PriceWaterhouseCoopers Utilities Global Survey 2004, “Security of supply has become the number one issue, and it will continue as a strategically important area for utility companies for years to come,” while “the increasing dependence on gas will become a mounting cause for concern.” There is therefore interest in the reappraisal of coal as a means
of bringing diversity and supply security to the power
generation fuel mix.
Then there are the environmental imperatives. If one is going to consider coal it must of course be clean coal and IGCC-based systems can perhaps offer the cleanest coal you can get, with potentially the lowest potential emissions (including mercury) of any coal generation technology. A further benefit is that IGCC lends itself to hydrogen production (as a possible power source for the much vaunted hydrogen economy) and, increasingly importantly, carbon dioxide capture. It is also worth noting that much of the carbon dioxide capture technology needed is already available and in use, although not in the power generation sector. One often cited example is the Coffeyville Resources ammonia fertiliser complex in Kansas (formerly Farmland - sadly another case of bankruptcy). This pet coke gasification facility uses UOP’s Selexol process to capture carbon dioxide, and according to UOP demonstrates this as a “commercialised technology.”
In the USA there is a small scattering of IGCC projects among the 90 or so new coal plants thought presently to be in the planning stage. To take one example, Cinergy, which has extensive IGCC experience through its Wabash facility in Indiana (believed by the utility to be “still the cleanest coal plant in the world”) has recently expressed interest in converting another of its older coal-fired units in Indiana (Edwardsport) to IGCC, although it would need government assistance to make the economics work. The current US administration has also demonstrated its belief in the potential of the technology, with the $1 billion FutureGen IGCC project a
centrepiece of its clean coal research and development efforts, significant incentives for gasification proposed in the ill-fated Federal Energy Bill and gasification proposals specifically invited under the Clean Coal Power Initiative (CCPI).
Speaking at the recent IChemE conference, “Gasification - a versatile solution”, Brighton, UK, 10-12 May, Gary Stiegel, Technology Manager, Gasification, at the USDoE’s National Energy Technology Laboratory, identified a number of new opportunities for using gas from coal gasification. These include repowering pulverised coal plants and refuelling “over 10 GWe of
existing natural gas combined cycle plants” and “over 12 GWe in existing warehoused gas turbines.” This would “take pressure off natural gas supply,” he said.
However, to really get things moving in the coal IGCC sector there are still formidable hurdles to be overcome. In particular, capital costs need to be reduced and perceived risks need to be addressed and managed, with industry proponents being willing to take an appropriate share (along with other funding agencies) of the risk burden. If the promoters of IGCC think the technology is so good they should be willing to invest in it. As Gary Stiegel.advised the assembled IGCC lobby in Brighton, “Stop looking for government handouts.”
Also important is the need for IGCC to clearly demonstrate where it has the edge over other proposed clean coal technologies. Illustrative of the issues to be faced are the reasons given by the Public Service Commission of Wisconsin for rejecting a proposal for a 600 MW
bituminous coal fuelled IGCC to be built as part of the Oak Creek expansion. “IGCC technology, while promising, is still expensive and requires more maturation,” said the Commission. In this case the cost estimates were $1579/kW for IGCC and $1400-1440/kW for supercritical pulverised coal (which was approved by the Commission). The IGCC in this case also showed a worse heat rate than the supercritical pulverised coal alternative, 9500 Btu/kWh vs 8850 Btu/kWh, which did not go down well with the Commission.
Another concern is the perception, based on problems with early IGCC plants, that the technology is unreliable.
However, Eastman Chemicals has been raising its profile in the IGCC sector in recent months and working hard to correct this impression. According to the paper by Bill Trapp of Eastman Gasification Services Company presented in Brighton, “Eastman has been operating a gasification facility for over 20 years at high reliabilities, demonstrating that a properly run facility can compete with and even exceed on-stream times of traditional coal fired plants.”
Optimism about IGCC is shared by GE, which is
planning to acquire ChevronTexaco’s gasification technology, citing the potential for cleaner coal as a principle reason. Getting the weight of GE behind IGCC in this way could prove to be the turning point that the industry has been looking towards for many years.
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