August 15, 2006

Currant Creek Power Plant, Mona, Utah

Odis F. Hill, Jr., PE, The Shaw Group, and Robert Van Engelenhoven, PacifiCorp

When Des Moines–based Mid-American completed the purchase of PacifiCorp from ScottishPower in late March of this year, one of its prizes was the new, natural gas–fired 525-MW Currant Creek Power Plant outside of Mona, Utah (Figure 1). Baton Rouge–based The Shaw Group Inc. (www.shawgrp.com), through its subsidiary Shaw Stone & Webster, provided all of the engineering, some of the procurement (PacifiCorp purchased the combustion turbines, the heat-recovery steam generators, the main transformer, and the switchyard components), and all of the construction services for the combined-cycle project—which is notable for having "gone commercial" twice, as we'll explain later.

 

 

 1. Flying high. PacifiCorp's new 525-MW Currant Creek Power Plant is 80 miles south of Salt Lake City, at an elevation of more than 5,000 feet. Courtesy: PacifiCorp

PacifiCorp, one of the lowest-cost electricity producers in the U.S., has 8,470 MW of net generation capacity representing a broad mix of fuels: coal, hydro, natural gas, wind, and geothermal energy. PacifiCorp operates as Utah Power in Utah and Idaho, and as Pacific Power in Oregon, Wyoming, Washington, and California.

In Utah, summer peak electricity demand has been growing at a sizzling 5% a year, about twice the national average of 2.6%. Accordingly, PacifiCorp's resource planners determined that the company's system would require new summer peaking capacity and new baseload capacity by 2005 and 2006, respectively. Thus the Currant Creek project was conceived as the first large (>300 MW) power plant built by PacifiCorp since 1983, when the third unit of the Hunter Power Plant in central Utah came on-line.

That the final bill for the project came in under $350 million (about $660/kW) shows that Shaw and PacificCorp know a thing or two about squeezing a plant construction dollar. For comparison's sake, a very similar, utility-built 2 x 1 plant equipped with the same gas turbines (but with a less-costly wet cooling system) that recently went into service in California cost over $410 million to build. Western ratepayers got a real bargain with Currant Creek (Figure 2).

 

 

Managing construction costs on this project was essential, due to its remote site, lack of rail access, and fast-track project schedule. To expedite erection and mitigate risk to craft labor, Shaw Group shops in Louisiana and Utah were used to assemble major pipe racks, large portions of boiler feedwater, main steam and reheat piping, and other modular components. These major subassemblies were then trucked to the 160-acre site when required as part of the construction sequence. This helped the site to achieve an excellent safety record: more than 1.5 million hours worked without a lost-time accident (Figure 3).

 

 

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