Coal, Gas

Supercritical Success

Issue 2 and Volume 104.

The October 1999 feature, “Supercritical Power Plants Hike Efficiency, Gain World Market Share,” provides much valuable information. It is especially timely because no supercritical (SC) or ultra-supercritical (USC) steam-turbine-based power units have been installed in this country since 1991 and many of the existing plants have not been upgraded for years. In the near future, these units will reach the age when further extending their lifetime becomes unreasonable. Replacing these units with new plants based on advanced (SC or USC) steam conditions is an option, but this should be prepared for in advance.

Along these lines, it is worthwhile to supplement the article with some additional up-to-date data. Of importance is the experience accumulated in the former Soviet Union (FSU). In operation in the early 1990s in the FSU were 180 standard 300 MW SC units, fifteen 500 MW units, fourteen 800 MW units and one 1,200 MW unit with the world’s largest tandem-compound (TC) high-speed turbine. These SC units have operated with reliability and availability characteristics higher then those of subcritical units, as well as those of the SC units at U.S. power plants. For example, in 1996 the average annual number of unscheduled outages for the 300 MW and 800 MW turbines in the FSU was 0.4, and the 1,200 MW turbine had no forced outages (I.A. Terent’ev, Elektricheskie Stantsii, 1998).

It should also be noted that even the largest new SC and USC plants have been designed for operating in a cycling mode. In particular, this capability was successfully confirmed by field tests of two USC double-reheat 700 MW units with steam conditions of 4,495 psi, 1050/1050/1050 F at Japan’s Kawagoe power station (T. Fushimi, VGB Kraftwerkstechnik, 1994).

Germany is actively pursuing construction of multiple coal-fired SC power plants. In parallel with new construction, however, existing units are also being refurbished to improve their efficiency, environment friendliness and longevity. Refurbishment of the 350 MW SC steam turbine at the Kiel cogeneration power plant, for example, increased the unit’s output by about one per cent (B. Michels, VGB Kraftwerkstechnik, 1997).

Last but not least, it is important to mention that modern high-temperature gas turbines with exhaust gas temperatures well above 1,110 F and once-through heat recovery steam generators (HRSG) make it absolutely realistic and reasonable to construct combined-cycle power plants with SC steam conditions. Such units could provide the highest operating efficiency. A pilot SC HRSG in Belgium is evaluating this concept (J.F. Galopin, Modern Power Systems, 1998).

Dr. Alexander S. Leyzerovich,Senior Consultant, Actinium Corp. Mountain View, CA


Unfettered Competition

It may come as a surprise to many that electric power customers can buy their electricity from any electric utility in the country right now. Not only now, but such a choice has been available for decades. It’s very simple. If an electric power customer thinks he can find a lower price or better reliability somewhere else, he can freely choose to move there! This is not my idea. In the early 1960s, Nobel laureate George J. Stigler made this observation as an argument against regulation.

In my opinion, the driving force behind national deregulation is electric customers actually exercising choice, that is, responding to national competition. Customers are fleeing territories of high rates caused by high demands due to large populations, heavy industries and aging generation and T&D infrastructures, taking their votes, businesses, jobs and taxes with them. PUC and FERC command-and-control of these territories has crippled their financial and creative abilities to respond effectively. This current quasi-deregulation fad is a last-ditch effort by these “smarter-than-the-marketplace” commanders to stem that loss of customers.

The solution to the electric utility industry’s woes is not quasi-deregulation, but unfettered marketplace freedom.

Name withheld upon request Colorado Springs, Colo.