Progress Energy Florida, a unit of Duke Energy (NYSE: DUK), is nearing an air permit approval that would cover three options for the coal-fired Crystal River Units 1-2, including installation of new flue gas desulfurization (FGD) scrubbers that would extend the lives of those facilities.
On July 31, the Florida Department of Environmental Protection sought public comment on a draft version of this permit case. On June 15, Progress Energy Florida submitted an air construction permit application for Crystal River Units 1-2 that includes these three options:
- commit to cease operation as coal-fired units by Dec. 31, 2020;
- install and operate an FGD system before Jan. 1, 2018, or within five years of the U.S. Environmental Protection Agency’s final approval of Florida’s final Regional Haze State Implementation Plan (SIP), whichever is later, and establish emissions standards of 95% SO2 removal efficiency or 0.15 lbs/MMBtu heat input from the units as presumptive Best Available Retrofit Technology (BART); and
- agree to a permit limit for SO2 by Jan. 1, 2018, or within five years of EPA’s final approval of Florida’s final Regional Haze SIP, whichever is later, at a level sufficient to exempt out of BART.
“If Crystal River Units 1 and 2 continue to operate as coal-fueled units beyond 2020, the company will install FGD technology,” the DEP noted. The supplementary information included analyses of wet and dry FGD scrubber options. However, the document indicated a preference by the applicant towards the latter due to reduced water use, volume of coal combustion products (calcium sulfite sludge or gypsum product), and lower capital costs (through less expensive carbon steel). Fabric filters are often used in conjunction with dry FGD technologies, especially when high efficiency SO2 removal is required. The reason is that the filter cake or lime that builds up in the bags provides additional contact between exhaust gases and reagent compared with an ESP,” DEP said. The department said a dry FGD technology, including fabric filters is the most likely scenario for the second option.
There are various types of dry and semi-dry FGD designs. The DEP used as an example, a system installed at the small AES Greenidge Unit 4 in New York. It features a hydrated lime-based scrubber and a fabric filter (baghouse) associated with the scrubber to optimize use of the hydrated lime sorbent. A circulating fluidized bed scrubber called TurboSorp was used at the AES Greenidge project.
To achieve 95% efficiency with a dry scrubber will require a baghouse. To achieve 0.15 lb SO2/MMBtu without a baghouse will likely require use of lower sulfur coal and require substantial upgrades to the existing ESPs, the DEP noted.
Crystal River Units 1-2 are smaller, older coal units. Unit 4-5 at Crystal River are newer, bigger coal units that got FGD installations late last decade. Unit 3 is a shut nuclear facility that new Progress Energy Florida parent Duke Energy is reviewing in terms of whether it would be cost-effective to restart.
The Crystal River complex, located near Crystal River, Fla., has four coal units capable of producing 2,295 MW. The site includes two units built in the 1960s, Units 1-2, and two units built in the 1980s, Units 4-5.
Life extension/FGD part of this plan goes against prior shutdown commitment
In late 2008, Progress Energy announced that it planned to shut down Units 1-2 in conjunction with the construction of a 1,100 MW nuclear power plant in nearby Levy County. Units 1-2 would cease to operate as coal-fired units by Dec. 31, 2020, under that prior plan. This date assumes timely licensing, construction and commencement of commercial operation of PEF’s proposed new nuclear units (Levy County Units 1 and 2). The shutdown of Crystal River 1- and 2 as coal-fired units is contingent upon completion of the first fuel cycle for Levy County Unit 2.
As for how it will handle that shutdown commitment in light of the new permitting of FGD for Unit 1-2, the DEP said: “The Department will in this permitting action supersede the contingent language under the shutdown option contemplated within the present application. The description of the option creates a possible new contingency put forward by the applicant based upon a ‘remaining useful life’ cost-effectiveness evaluation. The procedures for the evaluation are not clear and the caveat will not be included in this condition as it is implicit in the other options.”
Although not the subject of the present application, the emission trends at the adjacent Units 4 and 5 are relevant, DEP noted in the July 31 permitting description. Annual emissions and emission factors of both SO2 and NOX have been reduced by more than 90%. These reductions equate to 70,000 tons/year of SO2 and NOX combined. The reductions were achieved by installation of selective catalytic reduction and wet FGD scrubbers.
It is also worth noting that the future of the neighboring Crystal River 3 nuclear plant is uncertain. The nuclear plant has been offline since September 2009 and is not expected to reopen before 2014.