By Douglas J. Smith, IEng
TO MEET LOS ANGELES’ electric needs over the next several years, the Los Angeles Department of Water and Power’s (LADWP) integrated resource plan called for the installation of new generation equipment and the repowering of its older generating plants. As part of the plan, LADWP decided to install six new gas turbines in the Los Angeles basin. LADWP’s forecasts indicated these would be needed in 2003. Work started on the project in August 2000, about the same time as the state’s energy crisis. Because of the crisis, the project was put on an accelerated development schedule for an on-line date of summer 2001 rather than 2003.
After reviewing LADWP’s integrated resource plans, the South Coast Air Quality Management District (SCAQMD) determined that the total emissions produced by LADWP’s aging generators, plus the new capacity, would exceed the utility’s allowable limits. Because LADWP could also be called upon to generate more power to support the State of California during any energy crisis, SCAQMD issued an abatement order requiring LADWP to install the new gas turbines with BACT (Best Available Control Technology).
Realizing that they faced a tough construction schedule LADWP assigned the project to Richard Radmacher, a mechanical engineer with more than 29 years of experience. Over the years Radmacher has been responsible for other large projects, including the 1,700 MW Intermountain power plant in Utah and the 240 MW Harbor combined-cycle repowering project in Southern California.
Radmacher’s first priority was to order all of the equipment. After only three weeks to prepare the specifications and negotiate an agreement, the contract was awarded to General Electric (GE). In addition to supplying the six LM6000PC gas turbines, GE also supplied chillers, selective catalytic reduction (SCR) systems, transformers, gas compressors, circuit breakers and other ancillary equipment. In order to meet the tight schedule, GE utilized a modular design for the equipment.
LADWP selected two existing generating stations to install the equipment: Valley and Harbor. One LM6000 unit was installed at Valley and five were installed at Harbor. As these were existing sites, considerable site preparation work was required prior to construction. Utilizing their own work forces, LAPWP demolished the cooling towers at Valley and the fuel oil storage tanks at Harbor.
GE contracted with Black & Veatch to supply all of the engineering services. Black & Veatch’s scope included estimating the amount of steel, piping and cabling, preparing the bid specifications and preparing the final construction drawings.
Southern California’s 240 MW Harbor combined-cycle plant
Several construction proposals were received, and based on the lowest evaluated cost, the contract was awarded in January 2001 to TIC (The Industrial Company). Even after completing the demolition of the tanks at Harbor, there was still considerable fuel and fire protection piping that had to be relocated before construction could begin.
Planning was Critical
The construction contract, which included liquidated damages, was based on a six-day, 10 hour (6/10) schedule. However, in order to accelerate the schedule, the contractor was directed to prepare a schedule based on two 6/10 shifts. To accommodate the accelerated schedule, and to optimize the construction as drawings became available, a three-week “look ahead” schedule was developed.
Using the “look ahead” schedule, the day-to-day activities were detailed for the following three weeks, thus allowing the project manager to schedule labor, equipment and materials beforehand. When possible, construction was accelerated by working two 12-hour shifts/day. However, this schedule was only worked as the design progressed and the construction drawings became available.
Although the Valley site had adequate lay-down storage area, the Harbor site was very congested. The lack of storage area was overcome by utilizing multiple storage sites located outside of the plant. Major equipment such as the gas turbines were delivered and stored at the Valley plant and only transported to the Harbor plant once the foundations were ready.
The marsh-like soil at the Harbor plant, which is very soft, was another problem. However, this was resolved by installing more than 600 foundation piles.
Construction of the single unit at the Valley plant was completed in July 2001, and startup and testing was completed in August 2001. The unit went into commercial operation in September 2001. Because of the extra work involved in the installation of the foundation piles, the five units at the Harbor plant did not go into commercial operation until October 2001.
Water injection provides additional power and reduces NOx (nitrous oxides) to 25 ppm. The SCRs limit the CO (carbon dioxide) to 6 ppm and further reduce NOx emissions to 5 ppm. It is projected that the new generators will reduce LADWP’s total emissions in the Los Angeles area by 30 percent.