Exelon Generation LLC on May 18 petitioned the Illinois Pollution Control Board for a variance from a rule of the state Environmental Protection Agency which sets a Jan. 1, 2017, deadline for use of 15 ppm or less distillate fuel oil by fuel combustion emission sources.
Exelon Generation requested that the board grant this variance for four nuclear stations: Byron, Clinton, Dresden, and LaSalle.
Exelon Generation said it has been purchasing Ultra Low Sulfur Diesel (ULSD), which contains sulfur at 15 ppm or less, for many years and possesses records to demonstrate this fact. The nuclear facilities are required to maintain relatively large volumes of diesel fuel to power emergency generators, auxiliary boilers and fire pumps. Nuclear Regulatory Commission rules, and the environmental permits and regulations governing this emergency equipment, cause the fuel in the tanks to be used sparingly. Thus, many tanks at the facilities contain diesel fuel in excess of 15 ppm even after years of dilution with ULSD.
There are three potential options to come into compliance with the sulfur content rule: combust all of the higher sulfur fuel onsite at the facilities prior to Jan. 1, 2017; dilute the higher sulfur fuel onsite at the facilities prior to Jan. 1, 2017; or drain and clean the diesel fuel storage tanks and refill them with ULSD prior to Jan. 1, 2017.
“All three of these options impose an arbitrary and unreasonable hardship on Exelon Generation,” said the company. “As described in more detail below, the fuel in the tanks cannot be consumed or diluted by the deadline, and given the location of the tanks within secured areas of nuclear power facilities, it is logistically very difficult and potentially unsafe to drain and replace the contents of the tanks in the short time frame necessary to meet the January 2017 deadline. Finally, the environmental impact of the requested variance is inconsequential. The worst-case emissions associated with this variance request are less than two tons of sulfur dioxide per year. The variance likely will result in actual emissions of approximately one-tenth of a ton per year at all Facilities combined. These emissions will also be counterbalanced, in part, by reductions achieved by Dresden Station, which switched the primary fuel for its auxiliary boilers from diesel to natural gas on October 26, 2015. Accordingly, as described below, Exelon Generation seeks additional time to comply with the Sulfur Content Rule.”
Exelon Generation is requesting:
- Byron Station – a three-year variance from the sulfur content rule, extending the deadline for compliance to Jan. 1, 2020;
- Clinton Station – a four-year variance from the rule, extending the deadline for compliance to Jan. 1, 2021;
- Dresden Station – a three-year variance, extending the deadline for compliance to Jan. 1, 2020; and
- LaSalle Station – a five-year variance, extending the deadline to Jan. 1, 2022.