South Carolina Electric & Gas (SCE&G) has plans to retire or re-fuel six coal units as it responds to federal environmental mandates and strives to more than double its generation from “clean” resources, which includes renewables and nuclear.
The utility described those goals in an Integrated Resource Plan (IRP) covering the 2015-2029 period that it filed on Feb. 27 with the Public Service Commission of South Carolina. SCE&G said in that filing that it currently produces approximately 25% of its total generation from clean energy sources but by 2021 it expects to generate over 60% from clean energy.
Among its clean energy work related to coal, SCE&G continues to investigate and evaluate the co-firing of biomass and other engineered waste products in existing coal burning facilities. The goal of the project is to determine the operational practicality as well as the economic and fuel supply implications of co-firing in existing coal units. “Co-firing of biomass fuel in our existing units represents an opportunity to include additional renewable fuels in our production mix without having to build new facilities or spend significant capital on existing facilities,” the company noted.
To meet the compliance requirements for NOx, SCE&G (and an affiliate called Genco) has installed Selective Catalytic Reduction equipment (SCRs) at Wateree, Cope and Williams Stations. Also all coal-fired units have previously installed low NOx burners. To meet the compliance requirements for SO2, Williams and Wateree stations have had installed flue gas desulfurization (FGD) equipment, commonly known as wet scrubbers. Cope Station has FGD equipment in the form of a dry scrubber, which was part of the original equipment of that plant.
Mercury emission control has also been realized in the industry via the operation of FGD equipment. Consequently, the continued operation of the FGD equipment will contribute to SCE&G’s strategy for meeting the impending requirements of the U.S. EPA’s Mercury and Air Toxics Standards (MATS) that will become effective on April 16, 2015. A Chem-Mod coal additive being used at McMeekin, Cope, and Williams will also contribute to SCE&G’s efforts in stack emission control for mercury, as well as for NOx and S02.
In response to the EPA’s impending MATS, the last coal-fired boiler at the Urquhart Station, Unit 3, was converted to natural gas. Decommissioning of the plant’s former coal handling facilities was completed in 2014. Also in response to MATS, Canadys Station ceased operations in November 2013, and decommissioning efforts are still in progress.
SCE&G applied for and received a one-year extension on MATS compliance from South Carolina regulators for both McMeekin and Canadys. With the retirement of Canadys in the fourth quarter of 2013, only McMeekin has a waiver that will allow the continued use of coal until April 2016. SCE&G also requested a compliance extension for Williams Station, Cope Station, and Wateree in part due to the additional requirements of the reconsideration rule which dealt with startup and shutdown that was finalized in November 2014. This extension will also allow time to install additional pollution control devices that will enhance the control of certain MATS-regulated pollutants. These extension requests were recently approved.
Four of the targeted six are already gone as coal facilities
When the EPA promulgated MATS in 2011, SCE&G had six small coal-fired units in its fleet totaling 730 MW ranging in age from 45 to 57 years that could not meet the emission standards without further modifications to the units. They are:
- Canadys 1, 90 MW, commercial in 1962
- Canadys 2, 115 MW, commercial in 1964
- Canadys 3, 180 MW, commercial in 1967
- Urquhart 3, 95 MW, commercial in 1955
- McMeekin 1, 125 MW, commercial in 1958
- McMeekin 2, 125 MW, commercial in 1958
The company decided that these six units would be retired when the addition of new nuclear capacity was available as a replacement. As part of this plan, the company has retired Canadys Units 1, 2 and 3 and has converted Urquhart Unit 3 to be fired with natural gas. The capacity (250 MW) of the remaining two coal-fired units, McMeekin Units 1 and 2, is required to maintain system reliability until the new nuclear capacity is available. These units cannot run on coal after April 15, 2016, when their one-year MATS extension expires. The company expects to bridge the gap between the MATS compliance date and the availability of the new nuclear capacity by firing McMeekin Units 1 and 2 on natural gas and purchasing the balance of needed capacity.
In announcing its plans to retire these six units in its 2012 Integrated Resource Plan, the company was careful to note that its plans were subject to change if circumstances changed. Although this new IRP calls for the retirement of the six coal-fired units, the company said it will continue to monitor, among other things, developments in environmental regulation and will continue to analyze its options and modify the plan as needed to benefit its customers.
On the nuclear side, the utility is currently building two new units at its V.C. Summer station near Jenkinsville, South Carolina. Both units have the Westinghouse AP 1000 design. On Jan. 27, 2014, SCE&G and state-owned utility Santee Cooper agreed to increase SCE&G’s ownership share from 55% to 60% in three stages. SCE&G will acquire an additional 1% of the 2,234 MW of capacity when Unit 2 achieves commercial operation. An additional 2% will go to SCE&G one year later and another 2% one year after that. The expected completion date for Unit 2 is currently mid-year 2019 with Unit 3 expected to be complete about a year later.