Maryland PSC to take a little longer with review of revamped Mattawoman project

So the parties have extra time to look over some new project details, the Maryland Public Service Commission has pushed back by a couple of months its deadline for deciding on a 2013 application for the gas-fired Mattawoman Energy LLC project.

A March 10 motion to amend the procedural schedule was filed by several of the parties, including the company, to allow additional time to review amended filings by Mattawoman Energy. The final order target date had been in July of this year. The commisson judge handling this proceeding on March 13 granted that delay and the procedural schedule has been amended to:

  • July 10 – Intevenor’s pre-filed direct testimony due.
  • July 17 – All reply testimony due.
  • July 21-24 – Evidentiary hearing and hearing for public comment.
  • Aug. 11 – Initial briefs due (if necessary).
  • Aug. 19 – Reply briefs (if necessary).
  • Aug. 31 – Proposed order target date.
  • Sept. 30 – Final Order target date.

The project has gone through a major revamp

The parties are absorbing a Jan. 30 update on the project from the company that covers a major revamp and uprate for this facility.

“The purpose of this supplemental environmental review document (SERD) is to update the Maryland Public Service Commission (PSC) record with respect to modifications that have occurred to the proposed power plant site and linear facilities for the Mattawoman Energy Project,” said the filing. “First, Mattawoman Energy has made changes to the power plant equipment because the original equipment is no longer available. The changes in equipment include updated Siemens model combustion turbines (CTs) and an adjusted steam turbine (ST). The new model CTs are state-of-the-art power generation equipment, capable of producing energy with industry-leading efficiency. These changes result in an increase in electric generation from 889 to 990 megawatts (MW).

“The site layout also has been slightly adjusted to accommodate the new equipment. The limits of disturbance on the plant site have not significantly changed. In addition, modifications to the project’s electrical interconnection/generator lead line have been made since the substitute environmental review document (ERD) was submitted on June 30, 2014 (June 30 ERD). Instead of Potomac Electric Power Company (PEPCO) building a new 230-kilovolt (kV) transmission line to the plant site, Mattawoman Energy will design, permit, build, operate, and own a generator lead line. This line is approximately 2.5 miles long and extends from the power plant site north along existing linear facilities to a 230-kV PEPCO transmission line. Mattawoman Energy will construct a substation at this point of interconnection, which will tie into the Burches Hill substation.

“Engineering design and analysis for the gas pipeline and reclaimed water pipeline also have significantly progressed since the June 30 ERD filing. The general route for both pipelines remains the same, although construction techniques and construction and permanent maintenance easement widths have been further elaborated.”

Project uprated to 990 MW (net) from prior 859 MW

In its original certificate of public convenience and necessity (CPCN) application, Mattawoman Energy sought authorization to construct and operate an 859-MW natural gas-fired combined-cycle generating facility, consisting of two CTs, two heat recovery steam generators (HRSGs), and a steam tubine (ST), arrayed in a two-on-one configuration. Mattawoman Energy presented air quality and other analyses and information based on Siemens SGT6-8000H (223 MW) CTs and a Siemens SST-5000 (313 MW) ST.

Mattawoman Energy is now proposing to use updated Siemens model CTs (Siemens SGT6-8000H (optimized)), each with a gross nameplate rating of 286 MW and an adjusted SST-5000 ST, matching the greater heat and steam output of the CTs and HRSG units, with a nameplate rating of 436 MW. The total gross nameplate rating of the revised equipment is 1,008 MW; the net output nameplate rating, after subtracting 18 MW of auxiliary load, is 990 MW. The reason for this change is that Siemens no longer offers the earlier model.

Compared to the earlier model combined-cycle unit, the new Siemens model CTs, arranged in a two-on-one combined-cycle configuration with the complementary ST, will be capable of generating greater amounts of capacity and energy, which Mattawoman Energy plans to offer for sale in the PJM Interconnection-administered capacity and energy markets. The additional capacity and energy will play an important role in satisfying growing demand in Maryland and in the PJM region, the update said. Moreover, the new model CTs are state-of-the-art power generation equipment, capable of producing energy with industry-leading efficiency.

The Mattawoman Energy SGT6-8000H (optimized) net heat rate in combinedcycle mode at base load International Organization for Standardization (ISO) conditions with duct burner firing is 6,793 British thermal units per kilowatt-hour (Btu/kWh), making it one of the most efficient natural gas combined-cycle power plants available in today’s market.

Steven Tessem, Senior Vice President for Business Development of Panda Power Funds, the parent company of Mattawoman Energy, said in Jan. 30 supporting testimony that the company is working with PJM Interconnection on the project uprate. “[T]o accommodate the increased capacity associated with the revised power plant equipment, the capacity associated with the interconnection is likely to be modified in the future. To that end, Mattawoman Energy has submitted a supplemental request for an additional 116 MW of capacity injection rights, to which PJM has assigned queue number Z2-060. A feasibility study has been completed for this request and a System Impact Study is in progress.”

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.