Entergy Louisiana’s Ninemile Point plant has been powering New Orleans and southeast Louisiana since the 1950s. The facility in Westwego, just across the Mississippi River from New Orleans, comprises five dual-fuel boiler units, the oldest of which came online in 1951.
The plant currently has just under 2,000 MW of generation capacity in operation. That’s less than it used to, now that Units 1 and 2 have been retired, and Unit 3—commissioned in 1955—is nearing end-of-life. Replacing that capacity and upgrading its fleet in an area expected to see continued growth in electricity demand has been a priority for parent company Entergy.
In 2011, Entergy Louisiana spent $300 million to buy one of two 580-MW units at the Acadia Energy Center in Eunice from merchant generator Acadia Power Partners. That same year, sister company Entergy Mississippi purchased the 450-MW Hinds Energy Facility in Jackson, Miss., for $208 million. But keeping the Ninemile Point plant going meant building, not buying.
The project went out for bid in 2009, and in 2011, Entergy Louisiana proposed a new two-unit, 550-MW combined cycle plant at a price tag of $721 million. The Louisiana Public Service Commission approved the plan in 2012, and the Shaw Group (now CB&I) was awarded the engineering, procurement, and construction contract for the plant. Construction began that spring.
Several POWER editors toured the construction site in March, just before the ELECTRIC POWER Conference and Exhibition in New Orleans. The new Unit 6, still under construction with plans for a mid-2015 start-up date, will employ two dual-fuel General Electric 7FA gas turbines, each feeding a Vogt Power International triple-pressure duct-fired heat recovery steam generator, which will supply steam to a tandem compound Toshiba steam turbine. Each gas turbine is rated at 150 MW, with the remaining capacity supplied by the steam turbine. The plant is designed with substantial flexibility, allowing it to function as baseload generation or load following as needed.
Unit 6 will operate on natural gas, but has the ability to burn fuel oil if necessary. This is an important concern given the location, which was hit hard by Hurricane Katrina. In the event natural gas delivery is disrupted, the plant will be able to switch over seamlessly to fuel oil drawn from the on-site tanks. The building pad was also raised four feet to protect against possible flooding.
The new plant will be cooled by water from the Mississippi River like the other units, and Unit 6 actually took over the cooling water supply lines used by Units 1 and 2, meaning no additional work along the river and adjacent levee was necessary.
Though Entergy Louisiana will own Unit 6, it will use only 55% of its output. The remainder will go to Entergy Gulf States Louisiana (25%) and Entergy New Orleans (20%) via life-of-unit power purchase agreements.
Approximately 750 workers will be employed during construction, and 21 full-time positions will be created. Fuel savings over the units it replaced are expected to total around $26 million to $53 million per year.
—Thomas W. Overton, JD is a POWER associate editor (@thomas_overton, @POWERmagazine)