Detroit Edison banks on dry sorbent injection to save much of its coal capacity

DTE Energy’s (NYSE:DTE) Detroit Edison subsidiary is looking at various clean-air options for its coal-fired plants to meet the new clean-air regulations, said DTE in a Nov. 28 investor presentation.

New flue gas desulfurization and selective catalytic emissions controls are already in the process of being installed on 3,095 MW of capacity at the Monroe coal plant. Detroit Edison in 2009 began operating new FGDs on two of the four units at Monroe, with the other two units to get FGDs in the 2013-2014 period.

For the 1,260-MW Belle River plant, plans are to deploy either FGD or dry sorbent injection. There is another 1,500 MW of coal capacity at unnamed units where DSI should work, avoiding any retirements. There is an additional 1,000 MW of unspecified coal capacity that is highly dependent on whether DSI will work and may get retired beginning as early as 2015 in favor of new combined cycle gas turbine capacity. Then there is another 313 MW of unspecified coal capacity that is due to be retired.

Also, Detroit Edison is deploying facilities at three of its coal plants – Belle River, St. Clair and Monroe – that blend proprietary additives with coal, resulting in emissions reductions in excess of 40% for mercury and 20% for NOx.

Detroit Edison offered more specific details on upcoming power unit retirements, including coal retirements, in a Sept. 30 filing at the Michigan Public Service Commission in a power supply cost recovery plan case. Answering a question about a table showing projected annual changes over the next few years in generating capacity was Angela Wojtowicz, Manager of the Wholesale Power group in the Generation Optimization Department of the Regulated Marketing Organization at Detroit Edison.

“The projected capacity decrease in 2013 is associated with the retirement of the Dayton and Conners Creek diesel peakers,” Wojtowicz testified. “The projected capacity increase in 2014 is associated with the Ludington Unit 4 upgrade that is partly offset by a decrease associated with auxiliary power usage from flue gas desulfurization units (a/k/a scrubbers) proposed for installation in late 2013 and early 2014 on Monroe Units 1 and 2 respectively. The projected capacity decrease in 2015 is associated with possible retirement of Harbor Beach, River Rouge Units 2 and 3, St. Clair Unit 7, and Trenton Channel Units 7, 8, and 9 which are offset by the assumed addition of a combined cycle unit and the Ludington Unit 5 upgrade. The projected capacity increase in 2016 is associated with the Ludington Unit 1 upgrade.”

As for Cross-State Air Pollution Rule compliance, Wojtowicz said that the company was currently investigating the potential to further reduce NOx emissions with existing combustion controls, at the expense of reduced combustion efficiency. The company expects to get CSAPR compliance primarily with a combination of operational strategies such as higher percentage low-sulfur western coal in its blends with eastern U.S. coals, higher dispatch of lower-emission units and lower dispatch of higher-emission units.

Giving more detail about the dry sorbent injection installations mentioned in the November investor presentation, Wojtowicz said in the Sept. 30 testimony that the company is assuming the use of DSI on St. Clair units 1-4 and 6, and Belle River units 1-2. Harbor Beach, River Rouge units 2-3, St. Clair Unit 7 and Trenton Channel units 7-9 are assumed, for planning purposes, to be retired in 2015. “Such assumed retirements should not be construed as certain but present circumstances and expectations suggest the potential for such retirements,” Wojtowicz said.

The Sept. 30 filing wasn’t clear on which specific units are coal-fired. In a 2007 rate case at the PSC, Detroit Edison gave these breakdowns of its then-current coal capacity by its share of MW ownership and number of coal units at each plant: Belle River, 1,026 MW, two units; Harbor Beach, 103 MW, one unit; Marysville, 84 MW, one unit; Monroe, 3,115 MW, four units; River Rouge, 523 MW, two units; St. Clair, 1,368 MW, six units; and Trenton Channel, 730 MW, three units.

James Good, employed by Detroit Edison as Specialist – Fuel Resources, Fuel Supply, in the Sept. 30 testimony laid out the coal supply future for the utility over the next five years. The long-term forecast of coal prices used assumes the company’s continued reliance on low sulfur western (LSW) coal. For 2012, over 80% of all coal consumed is projected to be LSW coal. The LSW coal is procured from the Powder River Basin in Montana and Wyoming. The balance of the company’s coal is purchased from Central and Northern Appalachia.

The known factors that could affect fuel cost are the Reduced Emission Fuel (REF) projects at Detroit Edison’s Belle River, St. Clair, and Monroe plants. REF is a process that involves the application of chemical additives to the coal just prior to conveying the coal into the plant coal silos or bunkers. This process produces what is referred to as a Reduced Emissions Fuel and is done for the sole purpose of reducing emissions and their related costs. The Refined Coal is expected to reduce SO2, mercury (Hg), and NOx emissions and therefore the related emission allowance expense experienced by Detroit Edison, Good noted.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.