The Power of Teamwork

Energetic Schedule Brings Project Online in San Antonio

By Rob Patterson

To meet its summer peak power demands, San Antonio's City Public Service needed a 200-megawatt power plant that could come online at full load within 20 minutes. And the municipally owned electric utility not only needed quick power, it also needed the plant built quickly to meet possible summer 2004 demands.

Leon Creek Power Partners - a joint venture between the Steamboat Springs, Colo.-based TIC-The Industrial Company and Utility Engineering Corp. of Denver - was awarded the $43 million Leon Creek Power Plant and went from a July 2003 groundbreaking to generating power a mere 11 months later.

The two companies - who had partnered on other projects- formed the joint venture after the city issued a request for proposals to construct the plant. Utility Engineering provided design and engineering services; TIC acted as the general contractor.

Leon Creek Power Partners won the job thanks to a number of factors in its proposal: "Price, experience, safety record, the ability to meet the schedule and stability and financial backing," said Frank Sanfi of Parsons Brinckerhoff, who served as the owner's engineer and manager of the project. City Public Service hired the firm to prepare the request for proposal, evaluate the proposals and perform contract compliance and on-site monitoring.

"It was an extremely aggressive schedule," said Richard Cleveland, project engineer for TIC's Gulf Coast Region division, based in Houston. "Initially there were a lot of folks who felt that the schedule was unlikely to be achieved."

Two factors helped the project get up to speed. CPS had already purchased four General Electric LM6000 gas-fired, simple-cycle turbines, each capable of generating 50,000 megawatts. The turbines are able to begin generating power within 7 minutes and hit full capacity in less than 20 minutes, making them ideal for peak production usage. And a site was readily available adjacent to one of CPS's older plants, near Leon Creek at the southern edge of the city.

"We had infrastructure here already," said David Herbst, project manager for CPS. "We had a high-pressure gas supply fairly close." A new 2-mi. pipeline was laid to tap into the nearby main pipeline. "We also had a switchyard that lent itself fairly well to adding on a dead-end structure. We saved about $2 million with that. There was water supply on site. And the land was free - we already owned it." The older plant did create the complication of working around preexisting underground pipelines and water supply.

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To prepare the site, two cooling towers from decommissioned turbines in the older plant were demolished. A 5-ft. deep excavation removed some 40,000 cu. yds. of earth, which was replaced with fill. "One of the concerns is that the soil on site is a clay that swells up when it gets wet," said Sanfi. The fill mitigated any potential vertical rise underneath the plant.

Next, a 48,000-sq.-ft. reinforced concrete slab was poured using 8900 cu. yds. of concrete. At 5 ft. thick, the slab was not only designed to bear the load of the turbines and ancillary equipment, but also to address the vibrations created by the spinning turbines.

The four turbines were then installed, along with a fairly sophisticated support system to maximize efficiency and address environmental concerns. Each of the turbines is linked to a selective catalytic converter to reduce emissions. "You typically do not see those on a single cycle unit," said Clinton Smith, project manager for Utility Engineering's Amarillo-based Texas division. "It was a proactive move by CPS, who are emissions-conscious. From the standpoint of the entire community, they did a good thing there."

Since water supply is a concern in Central Texas, and the plant taps into the heavily utilized Edwards Aquifer, a reverse osmosis water-treatment system was incorporated into the plant to create maximum efficiency.

The four turbines are controlled by on-site Dell Computer servers using a Windows-based operating program and housed in a prefabricated steel structure. The system is designed to be controlled remotely by CPS's central dispatch facility, allowing the plant to be brought online without personnel on site.

In the end, teamwork overcame the demands of the tight construction schedule, "This is one of the smoothest projects I've been associated with," Cleveland said. "A lot of that is due to CPS's support. We approached everything together. The one thing we really enjoyed on this project is the true team among TIC, UE and CPS."