California plant adopts fast-start technology with four Siemens F-Class turbines

A substantial amount of gas-fired capacity has been added to the California Independent System Operator (CAISO) grid in the past few years. The newest plant to come online is NRG’s 720-MW Marsh Landing Generating Station, near Antioch on the Sacramento–San Joaquin River Delta.

(The new plant is expected to generate more electricity)

The four-unit simple cycle plant entered commercial operation on May 1, replacing the 1950s-era Contra Costa Power Plant on the same site. That two-unit steam plant was shut down in part because of its reliance on once-through cooling. The new plant will require only a tiny fraction of the old plant’s water consumption while generating more electricity.

The Marsh Landing plant is expected to supply all its power to Pacific Gas & Electric under a 10-year power purchase agreement. The fast-start facility was specifically designed to compensate for the large amount of wind generation in the area, much of it from nearby Altamont Pass.

Siemens has supplied the four SGT6-5000F gas turbines, four SGen-1000A generators, the SPPA-T3000 control system and auxiliary and secondary systems for the plant, as well as provided technical support with installation and commissioning. During commissioning, all four F-Class turbines demonstrated the ability to ramp up to full load in 12 minutes. Siemens’ fast-start “Flex-Plant” technology is also said to minimize transient emissions while ramping and the turbines expected to incorporate ultra-low NOx combustors and a selective catalytic reduction (SCR) system to control NOx emissions.

Builder Kiewit is said to have followed Leadership in Energy and Environmental Design (LEED) building standards in constructing the facility. According to John Chillemi, president of NRG's West Region, the fast-start technology employed by Marsh Landing also supports the integration of new renewable energy sources that are expected to come online over the next decade."

The project has seen some ups and downs since first being proposed. It was begun by Mirant in 2010 before its merger with RRI Energy to form GenOn, which merged with NRG last fall as construction was wrapping up. Despite the corporate musical chairs going on off-site, the project was completed on schedule at a total cost of around $700 million.

While much of the Bay Area, especially around San Francisco, has been markedly hostile to new fossil fuel–fired power plants, cities in the East Bay, such as Antioch, have thrown out the welcome mats in hopes of attracting jobs and tax dollars. San Francisco shuttered its last fossil plant in 2010, but Contra Costa County across the bay has opened four new plants since 1996, with several others in development. The relatively small area contributes about 7.5 percent of the state’s power. While local environmentalists have lamented the warm reception the plants have gotten, supporters have pointed out that most of them are replacing dirtier and less-efficient generation.