Raven okayed for DSI, new coals at Wagner plant in Maryland

A final approval came on Sept. 3 out of the Maryland Public Service Commission for new emissions controls for two coal-fired units at the H.A. Wagner power plant.

A law judge at the commission on July 30 issued a proposed approval order. Since there were no objections filed against that tentative finding, the project was deemed approved by the commission as of Sept. 3.

On Jan. 14, H.A. Wagner LLC had applied for a Certificate of Public Convenience and Necessity to authorize the modification of the Herbert A. Wagner Generating Station in Anne Arundel County, Md. The applicant is a wholly owned subsidiary of Raven Power Holdings LLC. Raven is an investor-owned energy holding company and is the owner of companies that in turn own three Maryland generating stations: Wagner, the adjacent Brandon Shores Generating Station, and the C.P. Crane Generating Station.

Raven bought these three plants in 2012 from Exelon (NYSE: EXC), which had agreed to sell them as part of its merger deal with Constellation Energy, the prior owner of the plants.

The Wagner site consists of two oil-fired and two coal-fired units (Units 2 and 3). This case involves the two coal-fired units at Wagner:

  • Unit 2 began operation in 1959 and is rated at 135 MW; and
  • Unit 3 began operation in 1966 and is nominally rated at 305 MW.

The applicant was seeking approval of two projects, to be used separately or in combination with each other. The projects are designed to bring Wagner Units 2 and 3 into compliance with the requirements of the U.S. Environmental Protection Agency’s Mercury and Air Toxics Standards (MATS), which restricts emissions of hydrochloric acid (HCl).

  • The first project proposed by Wagner would employ dry sorbent injection as an add-on to existing emission technology, which Wagner claims would enable existing emissions controls to remove more acid gas from the combustion stream.
  • The second project would employ very low sulfur sub-bituminous coal, either alone or blended with bituminous coal.

The initial plan is to burn sub-bituminous coal at Unit 2, and install the DSI system using hydrated lime on Unit 3. Unit 3 construction is to start by July 2015 and be completed in the first quarter of 2016. Changes to allow the sub-bituminous coal use at Unit 2 would be made in late 2014 or early 2015.

A company witness described the proposed DSI system as a technology for injecting sorbents, such as hydrated lime, into the flue gas stream of Unit 2 and/or Unit 3. The dry sorbent would be contained in four storage silos and be injected into the air heater outlet at each unit, where it would remove HCl from flue gas. The use of sorbents has been tested at Wagner and found to be technically feasible. Use of sub-bituminous coal has also been successfully tested and found feasible at Wagner.

The current primary coal type and source used in Units 2 and 3 is bituminous coal from Central Appalachia. The company indicated that the sub-bituminous coal would likely be from the Powder River Basin in the U.S., or from Adaro Coal in Indonesia.

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.