Polk Power Station

Polk Power Station

Polk Power Station, along with Tampa Electric's other power plants, serve customers across the West Central Florida service area.

Location

Polk Power Station occupies 4,300 acres on State Road 37 in Polk County, Florida. It is located approximately 40 miles southeast of Tampa and about 60 miles southwest of Orlando.

Description

A state-of-the-art integrated coal gasification combined-cycle (IGCC) power plant, Tampa Electric's Polk Power Station produces enough electricity to serve 75,000 homes.

Polk Unit One is located on unmined land surrounded by former phosphate mining land to the east, and a berm developed as a cooling reservoir to the south. The design of the cooling reservior maximizes plant water recycling while minimizing groundwater withdrawal and offsite discharges.

The 260-megawatt IGCC facility began commercial operation in the fall of 1996. Construction on Polk Unit Two began in 1998 and Unit Three in 1999. These two 180-megawatt simple cycle combustion turbines use natural gas and distillate oil to generate electricity. Unit Two and Unit Three started commercial operation in July 2000 and May 2002 respectively. Polk Units four and five, two 160-megawatt (MW) units were completed in April 2007. The two new simple-cycle peaking units use natural gas to generate electricity.

Technology

The 260-megawatt IGCC facility is among the nation's cleanest, most efficient and most economical power generation units. The plant is a first-of-its-kind combination of two leading technologies.

The first technology is called "coal gasification," which uses coal to create a clean-burning gas. The second technology is called "combined-cycle," which is the most efficient method of producing electricity commercially available today.

The plant combines coal with oxygen in the gasifier to produce the gaseous fuel. After processing, the clean coal gas is used in the combustion turbine to produce electricity.Combined-cycle technology increases efficiency because it reuses exhaust heat to produce more electricity.

Combined-cycle design consists of a combustion turbine, a heat recovery steam generator, and a steam turbine. The exhaust heat from the combustion turbine is recovered in the heat recovery steam generator to produce steam. This steam then passes through a steam turbine to produce more electricity.

A complete review of the technology in use at Polk Power Station is available in this report to the Department of Energy.

Environment

The coal gasification unit provides clean, coal-fueled power, with a minimum removal of 95 percent of the sulfur from the coal gas. This exceeds the performance of today's most advanced coal-fired generating units. Furthermore, nitrogen oxides emissions are also lower than many of today's most advanced coal-fired generating units. The sulfuric acid and solid byproducts are then sold for industry use.

The plant is considered “zero process water discharge.” A brine concentration unit, which produces an effluent that is reused in the process, handles all of the liquid waste.

The combined-cycle technology requires much less cooling water than conventional technology, and Tampa Electric was able to modify existing conventional “mine cuts” on the phosphate land to become the plant's cooling reservoir.

With a March 2009 agreement, Tampa Electric established an innovative public-private project 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 via the Alafia River. The 30-year agreement will benefit the environment by reducing wastewater release. It will also maximize the beneficial reuse of reclaimed water using Tampa Electric's Polk Power Station, ensure that the Polk Power Station site has a reliable water supply for potential future generation capacity additions, and reduce the amount of future groundwater withdrawals at the Polk Power Station.

History

TECO Energy's independent power subsidiary and a partner were awarded $120 million from the U.S. Department of Energy (DOE) for the development of a project using clean coal technology. As part of a cooperative agreement with the DOE, TECO Energy is also concentrating on commercialization of this IGCC technology.

Construction on Unit One began in 1994 on a site selected by a public Power Plant Siting Task Force comprised of 17 citizens from environmental groups, businesses, and universities in the Tampa Electric Company service area and throughout Florida. The objective of the Power Plant Siting Task Force was to ensure that local and statewide public issues and environmental concerns relative to new power plant development were adequately and accurately considered in selecting a suitable site for the new power plant.