VIsiting the nation's first greenfield commercial IGCC power plant

POWER-GEN International 2010 got off to a quick start Monday morning when I, along with 45 other show and conference attendees, had the opportunity to tour the 260 MW Polk Power Station, the nation's first greenfield integrated coal gasification combined-cycle (IGCC) power plant.

The Tampa Electric Co.-owned Polk Power Station was constructed on a 4,300- acre piece of land that was once used for phosphate mines. The IGCC plant, referred to as Unit 1, is a first-of-its-kind combination of two technologies, coal gasification and combined-cycle, that began commercial operations in 1996.

Oxygen-blown gasification, a technology originally developed by Texaco and then purchased by General Electric, combines coal that is stored on-site in two 5,000 tons silos at the Polk plant with oxygen in the 40-foot-tall GE gasifier to produce the fuel syngas. After processing, the clean coal gas is used in the GE 7FA combustion turbine to produce electricity.

To generate even more power at the same plant, the combined-cycle design takes the "waste" exhaust heat from the 7F turbine, recovers it in the HRSG to produce high-pressure steam that then passes through GE D11 steam turbine. When firing with syngas, the IGCC heat rate at Polk is about 9,300 Btu/kWh.

Vernon Shorter, a consultant for TECO who led the plant tour, said power providers “should consider this technology because of the environmental benefits and efficiency.”

Built with $140 million of support from the U.S. Department of Energy as part of its Clean Coal Technology program, the Polk station operates at 90 percent availability with over 98 percent SO2 reduction, and 90 percent NOX control. The plant is also considered zero process water discharge, which DOE recognized as among the world’s cleanest. The combined-cycle technology requires less cooling water than conventional technology and TECO was able to modify the existing mine cuts to act as the plant’s cooling reservoir. And in March 2009, TECO established an agreement with the City of Lakeland and the Southwest Florida Water Management District to supply Polk Power Station with up to five million gallons of treated reclaimed water daily that would otherwise be discharged into Tampa Bay.

For TECO to meet summer demand, the Polk station has four additional simple cycle GE 7FA combustion turbines on site that were brought online between 2000 and 2007. Unit 2 and Unit 3 are 180 MW duel fuel turbines that are fired with natural gas and distillate oil, while the 160 MW Units 4 and 5 operate using only natural gas.

The Polk IGCC station has operated on over 20 different fuels, including coals, coal blends, coal/petroleum coke blends and coal/coke/biomass blends.

“This plant has produced more megawatts than any other IGCC plant in the world,” said Shorter.

Although the plant was not in operation the day we toured it due to a problem with the sulfur removal plant, an occurrence that is rare, added Shorter, the tour was informational. It was my first tour of an IGCC facility, along with many of the other visitors, and I recommend visiting the facility if the opportunity ever becomes available.

Oyster Creek plant closing, will others follow?

On Dec. 8, Exelon announced that the Oyster Creek nuclear power generating facility in New Jersey will be shut down by 2019, roughly 10 years before the plant’s operating license expires. The 619 MW Exelon-owned nuclear plant, the oldest in the U.S., is shutting down instead of building cooling towers that the New Jersey Department of Environmental Protection has been pushing for. Exelon’s Chief Nuclear Officer, Christopher M. Crane, told the New York Times that installing cooling towers “would cost us significantly more than the current value of the plant.”

Exelon received an estimate in 2006 that it would cost $700 to $800 million for the 40-year old plant to install cooling towers. Because every nuclear plant is unique, cooling towers must be designed specifically for each site. When I spoke with plant spokesman David Benson for a story in the October issue of Power Engineering magazine, he also said the retrofit estimate is “more than the plant is worth.”

“If we were forced to put up cooling towers, we would have to close the plant.”

Now, it appears that Benson was correct. Many nuclear power plants in the United States are going through feasibility studies to consider technologies to comply with an expected revision to Section 316(b) of the Clean Water Act, which sets out rules related to fish impingement and entrainment. 316(b) requires that the location, design, construction and capacity of cooling water intake reflect the best available technology for minimizing the environmental impact on fish and other aquatic life. Regulations for existing facilities under section 316(b) were previously made known in both 2004 and 2006 under Phase II. Litigation followed both of these actions, and now EPA is looking to combine and re-proclaim rules for all existing cooling water intake structure facilities.

The biggest push has been for power plants to install cooling towers to reduce the amount of water used to cool the plants. EPA estimates that over 200 billion gallons of water per day are withdrawn by manufacturing facilities and power plants.

But Benson said Exelon has made investments over a number of years to reduce the plant’s impact on Barnegat Bay, the body of water that the plant uses for cooling. According to Benson, “DEP has pointed out that we have wedge wire technology that is as good as it gets and we are always looking for updated technology.”

After Oyster Creek is closed by the end of 2019, Exelon will take about two years to put its components in layup. The company has about $750 million for decommissioning, but will not tear down the plant for at least 10 years after closure.

This announcement comes on the same day that The Brattle Group, an economic consulting firm, released a report that said around 11,000 to 12,000 MW of coal-fired generation could retire if cooling towers are mandated.

So the U.S. could see large amounts of power generation begin to go offline, like Oyster Creek, if the EPA does require plants to install cooling tower technology. Although the rule would not pertain to only nuclear plants, in the U.S. 35 of the 104 active nuclear power reactors currently use closed-cycle cooling towers while 60 use once-through cooling technology. EPA said that while their information on impact is limited, the agency claims it does know that trillions of aquatic organisms are impinged or entrained annually. EPA also said that 40 percent of all cooling water intakes are on water bodies that have threatened or engaged species.

“If the new rule is prescriptive and states that everyone needs to install cooling towers, that is huge for the industry,” said Greg Allen, director of environmental and engineering services for Alden Research Laboratory. “It is very difficult to retrofit cooling towers at existing plants.”

So now the power industry must wait for EPA to make a decision on 316(b) in order to determine the fate of numerous power plants. Retrofits may be an option for some plants. But like Benson and Crane said, it can also be expensive. EPA is finalizing an estimation of the proposed rule's likely cost and plans to issue a final rule in mid-2012.