Idaho Power sees need for DSI at North Valmy, SCR at Bridger

Currently, the only notable investment required at the North Valmy coal-fired power plant for clean-air compliance is to install a Dry Sorbent Injection (DSI) system for compliance with the Mercury and Air Toxic Standards (MATS) on Unit 1.

“North Valmy is not subject to Regional Haze (RH) Best Available Retrofit Technology (BART) regulations; therefore, no additional controls will be required for compliance with this regulation,” said Idaho Power in a 2011 Integrated Resource Plan (IRP) update released Feb. 14. “No other notable investments in environmental controls at the North Valmy plant are required at this time.”

Idaho Power is a 50% owner of North Valmy, located in Nevada, along with 50% owner and plant operator NV Energy.

Installation of DSI was the lowest cost result for most of the sensitivities analyzed by consultant Science Applications International Corp. (SAIC), including the planning case scenario (planning case natural gas/planning case carbon). The AURORA analysis, performed by Idaho Power, shows installing DSI as the least-cost option in four of the nine sensitivities analyzed, including the planning case scenario (planning case natural gas/planning case carbon). The scenarios in which DSI was not the preferred option are the extreme low natural gas price and high carbon cost cases.

Idaho Power’s conclusion is that installing the DSI system is a low-cost approach to retain a diversified portfolio of generation assets, including the 126 MW of Unit 1 capacity for its customers’ benefit. The continued operation of Unit 1 as a coal-fired unit will provide fuel diversity that can mitigate risk associated with high natural gas prices, the utility noted.

If North Valmy requires major additional capital or operation and maintenance costs (O&M) spending for new environmental regulations, both the SAIC and the Idaho Power analyses advise further review to justify the additional investment.

SCR for Jim Bridger units also in the works

Also, Idaho Power owns one-third of the coal-fired Jim Bridger power plant in Wyoming, along with two-thirds-owner PacifiCorp. Jim Bridger is currently required to install Selective Catalytic Reduction (SCR) on all four units for regional haze (RH) compliance and mercury controls for compliance with MATS. Both the SAIC and Idaho Power evaluations identify additional investments in environmental controls on all four Jim Bridger units as prudent decisions that represent the lowest cost and least risk option. Idaho Power recommends installation of SCR and other required controls on Units 3 and 4 and including the continued operation of all four Jim Bridger units in its future resource planning.

The current plan is to have the new Jim Bridger Unit 3 SCR operating in 2015 and the Unit 4 SCR in 2016, with the other two SCRs further out (Unit 1 SCR operating in 2022 and Unit 2 SCR in 2021).

Idaho Power also evaluated the economic benefits of delaying coal unit investments required under the emerging environmental regulations. Idaho Power assumed it could negotiate with state and federal entities a five-year period where no additional environmental controls are installed in exchange for shutting the unit down at the end of the five-year period. These compliance timing alternative cases are strictly hypothetical. “Idaho Power may not have any basis under current regulations to negotiate this delay, and the relevant regulatory authorities have not offered any such delay,” the utility said.

Any decision regarding environmental investments, plant retirement, or conversion to natural gas must be coordinated and agreed to by the other owners/operators of these two coal plants and their regulators, the utility said.

Idaho Power has revised its near-term action plan as part of the 2011 IRP Update, with the plan elements being:

  • 2013 Integrated Resource Plan—Prepare and file by June 30, 2013.
  • Boardman to Hemingway Transmission Line—Ongoing permitting, planning studies, and regulatory filings.
  • Gateway West Transmission Line—Ongoing permitting, planning studies, and regulatory filings.
  • North Valmy Unit 1 DSI—To comply with the Mercury and Air Toxics Standards, this unit will require a DSI system to be operational by March 2015. Idaho Power anticipates the company will be required to commit to the installation of the DSI system no later than the third quarter of 2013.
  • Jim Bridger Unit 3 SCR—To comply with the Regional Haze-Best Available Retrofit Technology regulation, this unit will require SCR to be operational by Dec. 31, 2015. Idaho Power anticipates the company will be required to commit to the installation of the SCR by the second quarter of 2013.
  • Jim Bridger Unit 4 SCR—To comply with the RH-BART, this unit will require SCR to be operational by Dec. 31, 2016. Idaho Power anticipates the company will be required to commit to the installation of the SCR by the second quarter of 2013.

Both coal plants represent a lot of capacity for Idaho Power

The Jim Bridger plant consists of four units and is located near Rock Springs, Wyo. These units have the following current net dependable capacity ratings:

  • Jim Bridger Unit 1 (531 MW)
  • Jim Bridger Unit 2 (527 MW)
  • Jim Bridger Unit 3 (530 MW)
  • Jim Bridger Unit 4 (523 MW)
  • Total Plant – 2,111 MW (703.7 MW Idaho Power Share)

The following major emission control equipment has been previously installed on each unit at the Jim Bridger plant:

  • NOx control – New Generation Low NOx Burners, 0.26 lb/MMBtu emissions rate
  • Opacity control – Electrostatic Precipitators, 20% opacity
  • SO2 control – Wet Scrubbers, 0.15 lb/MMBtu emissions rate

The North Valmy plant consists of two units and is located near Winnemucca, Nev. These units have the following current net dependable capacity ratings:

  • North Valmy Unit 1 (252 MW)
  • North Valmy Unit 2 (272 MW)
  • Total Plant – 524 MW (262 MW Idaho Power share)

The following major emission control equipment has been previously installed at the North Valmy plant:

  • NOx control – Early Generation Low NOx Burners, 0.46 lb/MMBtu (averaged)
  • Opacity – Baghouse, 20% opacity
  • SO2 (Unit 2) – Dry Lime Scrubber, 70% removal

In the process of preparing this IRP update, Idaho Power considered and rejected an exit from coal-fired power completely. The utility said this study shows that keeping its coal-fired power plants in the utility’s long-range plan is economically preferable to other options despite anticipated expenses for stricter environmental controls.

“Based on the research and the facts as we know them today, it’s clear that continuing to maintain and upgrade our coal plants is the best option for our customers, both in terms of cost and in reducing risk by maintaining a diverse resource portfolio,” said Tom Harvey, joint projects manager for Idaho Power, a unit of IDACORP (NYSE: IDA).

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.