Alcoa modernizes four-powerhouse, 216-MW Yadkin

Even as its relicense application moves through the federal process, Alcoa Power Generating Inc. is conducting a modernization program at the 216.38-MW Yadkin project that incorporates mitigation proposed in its relicensing settlement.

Alcoa already is into the third year of a 16-year program to modernize Yadkin’s four powerhouses on the Yadkin River in North Carolina. The Yadkin modernization program, outlined in 2004, calls for an upgrade to the project’s system-wide supervisory control and data acquisition (SCADA) system as well as various work at each powerhouse, High Rock, Tuckertown, Narrows, and Falls.

An important facet is a multi-million-dollar investment to increase dissolved oxygen levels and improve water quality at the four developments, as anticipated in the relicensing settlement filed with the Federal Energy Regulatory Commission (No. 2197).

�With Yadkin’s FERC relicensing effort in the final stages of negotiations, water quality (dissolved oxygen) is an important issue,� an Alcoa statement said. �Yadkin’s water quality plan is part of the February 2007 relicensing settlement agreement. It contains information on the above-mentioned D.O. enhancements as well as a D.O. monitoring plan and the potential for future D.O. enhancement, if necessary.�

Dissolved oxygen mitigation slated for High Rock, Narrows

As a result, modernization work at High Rock includes dissolved oxygen enhancements via “through-the-blade” atmospheric air admission in the turbines. Additionally, at Narrows, work includes dissolved oxygen enhancements via atmospheric air admission in the draft tube cone.

Other modernization at all four powerhouses includes:
o Substation upgrades, including new transformers in all but Falls;
o Turbine modeling for new runners with additional capacity and life extension of other water path components;
o Generator rewinds at all but Narrows;
o New governors, and controls;
o New switchgear at all but Narrows; and
o Powerhouse crane refurbishment at all but Tuckertown.

Fluor, Alcoa’s engineering, procurement, construction, and management partner, is the project manager. Alcoa also has a partnership agreement with Voith Siemens Hydro Power Generation for engineering, design, and installation of equipment. ABB is supplying and installing the new transformers. Alcoa said it contracted with regional engineering companies and contractors for balance-of-plant work.

Alcoa said it is revising the program’s estimated cost, which had been set at $141 million.

Draft environmental assessment expected in September

Alcoa said it expects FERC to issue a draft environmental assessment of the relicensing application in September. Alcoa’s current hydro license expires April 30, 2008.

The final relicensing agreement between Alcoa and stakeholders was filed with FERC earlier this year. (HNN 8/22/06) It calls for actions to reduce generation during drought, boost dissolved oxygen, and improve water quality on the Yadkin River. In the past week, Alcoa said it was asking FERC for permission to reduce flows and balance reservoir water levels due to a current extreme drought.

Alcoa began modernizing Yadkin in January 2001, with the upgrade of Narrows Unit 4. However, due to changes in business conditions that same year, Alcoa put work on hold for the remaining units at Narrows and for High Rock and Falls. In 2004, it developed a new, 16-year plan for Yadkin.

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