Update: What’s That Scrubber Going to Cost?

George W. Sharp

Pages: 1 2

Flue gas desulfurization (FGD) projects continue to be the largest line item for many utility construction budgets. The technology is sound, so the operational risks have decreased remarkably over the past decade. What remains, however, is the risk of project overruns caused primarily by rapidly rising commodity prices. In our 2007 survey (for which data were collected in 2006) we found that the base cost of an FGD system was $319/kW averaged over 49 separate projects. That was an increase of 21% since the previous survey was completed in 2005. Much has changed since that report was presented in the July 2007 issue of POWER.

Survey Background

The data for the current survey were collected during the period December 2007 through June 2008 and then presented to the Fossil Productivity Committee (FPC) at the EUCG fall meeting in late 2008 (see sidebar, "Inside the EUCG"). There are important differences between the two surveys. First, the number of utility participants remained the same, at an even dozen, although there were four new participants. The survey continues to cover an excellent cross-section of coal-fired utility plants involved in FGD retrofits (Figure 1).

Inside the EUCG

The EUCG is an association of electric utility professionals that provides a forum in which utilities can improve their operation and maintenance practices and construction performance. Now in its 24th year, the EUCG holds technical conferences and workshops twice yearly for the purpose of information exchange. The organization (formerly known as the Electric Utility Cost Group) is organized into committees and working groups by interest area, such as fossil, nuclear, and hydroelectric plants; transmission and distribution; financial management; and IT.

One of the EUCG’s key activities is developing process and market benchmarks, unit reliability strategies, and best-practice applications to foster performance and cost excellence within the utility industry and competitive markets. The EUCG’s Fossil Productivity Committee has 32 electric utility members reporting operating data on more than 300 individual coal-fired units. That number represents more than 30% of operating coal plants in the U.S.

For more information about the EUCG, contact Pat Kovalesky, executive director, at 623-572-4140 or visit www.eucg.org.

1. New survey update. The 2008 EUCG flue gas desulfurization (FGD) cost survey includes 78 units totaling 41 GW. Source: EUCG

Total project costs [for a flue gas desulfurization system] reported in the 2008 survey were approximately 28% higher than those reported in the 2007 survey.

The 2008 survey covered more than 41 GW and 78 scrubbed units and represents the largest FGD data set analyzed in the industry. The average unit size in this survey was 956 MW, down slightly from 1,019 MW in the 2007 survey.

The survey data reflect the wide variety of plants, locations, and fuels used in this industry. The survey also covered a nice range of FGD system start-up dates (Figure 2). Nearly 50% of forecasted in-service dates were 2009 and 2010, the average start-up date is 2010, and the latest is 2015. As the reported start-up dates are in the near future, we have high confidence in the final construction cost estimates, which reinforces the usefulness of the data. We have included results from the 2007 survey in the figures to illustrate recent industry cost trends for FGD systems.

2. Latest cost data. The majority of the survey data come from scrubbers that were recently installed or are currently under construction. Source: EUCG

System design characteristics and assumptions for units covered in the current survey were not unlike those in the 2007 survey and are summarized below:

All the surveyed facilities are using limestone forced oxidation technology.
Tower technology selection varies by site, although more than half of the units still prefer spray technology (Figure 3).
The FGD average sulfur dioxide removal design basis selected by respondents remained in the range of 4.0 to 4.9 lb/mmBtu, although the number of respondents reporting the mean value almost doubled (Figure 4).
Sixty percent of the respondents stated that their design includes a single stack/double flue configuration; another 29% specified a single stack/single flue design. These results are very similar to the 2007 survey data.
There was more agreement with the flue material selection. In 79% (70% in 2007) of surveyed plants the flue is fiberglass resin; 12% (14% in 2007) selected an alloy steel or C-276 clad flue.
For FGD waste disposal, 60% (53% in 2007) of respondents are using an old or new landfill; slightly fewer (26%) are recycling at a wallboard plant (35% in 2007).
Reagent prep delivery is mostly by truck (57%); the remainder use rail (24%) and marine vessel (17%). These results are within a few percentage points of the 2007 survey results.