Air Pollution Control Equipment Services, Coal, Gas

Largest Gas-fired Recip Plant in U.S. Goes Commercial in Colorado

Issue 7 and Volume 106.

By Steve Blankinship, Associate Editor

The largest power facility in the U.S. using natural gas to fire reciprocating engines was declared commercial in May. The 111 MW Plains End plant, located near Denver, is composed of 20 Wärtsilä 18V34SG units rated at 5.7 MW each. PG&E National Energy Group (NEG) owns the plant and Public Service Company of Colorado will dispatch all the power it produces. The peaking facility is permitted to operate up to 6,000 hours per year.

Although the biggest such installation to date, the plant’s configuration is one of four similar plants installed in the U.S. based on Wärtsilä’s PeakingPlus concept. “PeakingPlus was chosen for its fast delivery time and ability to operate at peak efficiency even at high altitudes – two criteria that many of the gas turbine power plants sold today cannot match,” said Thomas M. Carbone, president of Wärtsilä North America.


Composed of 20 5.7 MW Wartsila units, NEG’s Plains End facility is the largest gas-fired reciprocating plant in the U.S. Photo courtesy of Wartsila.
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Introduced in October 2000, PeakingPlus is a line of modular, ready-made power plants that allow users to generate their own power when electricity demand peaks. Developed to address the unique peak and intermediate energy requirements in the U.S., PeakingPlus is the first reciprocating engine plant tailored to the larger scale gas-fired peaking market.

“Compared to the gas turbines used in similar U.S. power plants, Wärtsilä’s reciprocating engines offer 50 percent faster delivery times; a scalable design that more closely matches most customer needs; no continuous water requirements; and an approximately 23 percent increase in efficiency,” said Carbone. He noted that start-up from warm stand-by status to full electrical output takes less than 10 minutes. “This is an important WSCC criteria for an electrical generating plant’s stand-by status, with Plains End achieving the most demanding status,” he said.

“Additional benefits provided by this facility include local voltage support and load following at a constant heat rate of about 9200” says Kent Fickett, Senior Vice President of Strategic Initiatives at NEG. NEG owns and manages more than 7,000 MW of generating capacity and has more than 10,000 MW of new capacity in development and construction.

The heart of the emissions control is the modern spark ignition lean burn technology. The low emissions from the lean burn, pre-chamber design are further reduced with catalyst removing VOCs and CO from the exhaust gases before they go to atmosphere. Additional NOx control is provided by the SCR system that uses urea as its reagent. Permitted particulate level for Plains End is 0.031 lb/MMBtu heat input.