Exelon Generation announced Sept. 29 that it is planning to build two combined-cycle gas turbine (CCGT) units in Texas utilizing a new General Electric technology that will make them among the cleanest, most efficient CCGTs in the state and the nation.
The new units are being built on existing Exelon sites: at the Colorado Bend Generating Station, currently a 498-MW natural gas plant in Wharton County; and at the 704-MW Wolf Hollow natural gas plant in Granbury. Each new unit will add approximately 1,000 MW of capacity to their respective sites.
Alstom Power will provide the Heat Recovery Steam Generators (HRSGs) to produce the steam necessary to maximize generating capacity and efficiency at each unit. Additionally, the new units will be cooled with air instead of water, a critical need in arid Texas.
“Exelon is a forward-looking company, and what we see is a clean energy future that includes this kind of new technology, which uses little water and produces few emissions while generating electricity at a very low cost,” said Ken Cornew, president and CEO of Exelon Generation. “We’re delighted to be the first to employ this GE technology, and we’re delighted to do it in Texas.”
Victor Abate, president and CEO, power generation products at GE Power and Water, said: “These combined cycle plants will use our air-cooled 7HA.02 gas turbines, which provide the most output, highest efficiency and best operational flexibility for 60 Hz applications. They are designed to start fast, ramp up more quickly and turndown more efficiently than any other H-class turbine on the market today. This translates into enabling Exelon to deliver power quickly when it is needed and to ramp down when it is not.”
A simplified design approach provides for easier construction and maintenance, making these units among the most predictable and least costly to operate and maintain in the industry, Exelon noted. The HA turbines apply advanced materials from GE aircraft engines, incorporating single-crystal alloys and thermal barrier coatings to deliver longer parts life for lower lifecycle costs. This enables the turbines to operate at higher temperatures (over 2,600 degrees F), increasing efficiency and further reducing ongoing maintenance costs. GE has more than 100 million hours of single-crystal experience, and has been testing and developing thermal barrier coatings and ceramic matrix composites for 15 years.
John Zachry, CEO and Chairman of Zachry Holdings, stated: “We are pleased to be working with Exelon to help meet the expanding electric energy needs in our home state by deploying efficient, advanced-class, combined cycle generating technology. More than 1,000 of our highly-skilled engineering, procurement and construction employees will work on these two very important projects.”
Construction of the units is expected to begin in 2015 with commercial operation targeted for 2017. These projects will bring approximately 1,000 engineering and construction-related jobs and 17 permanent operations jobs to the communities surrounding these sites.
GE said Sept. 29 that is more than half-a-billion-dollar order, and that Exelon will purchase four 7HA gas turbines, two D600 steam turbines, six generators and a contractual service agreement for the Wolf Hollow and Colorado Bend gas combined-cycle projects. This represents the first U.S. order for GE’s highest efficiency HA turbine, adding to recent orders in Japan, France and Russia. The equipment is expected to ship in 2016, and the plants are due to be operational in 2017.
The 7HA.02 gas turbine offers output of 330 MW per unit, a net combined-cycle efficiency of more than 61%. The HA gas turbines also feature modular constructability for a shorter installation schedule, a real benefit in Texas given concerns about skilled manpower availability.
“We have invested more than $1 billion in our latest H-class technology to deliver the most cost-effective, dispatchable power to consumers,” said Abate. “We are excited to work with Exelon on H-class power generation projects, the fastest growing segment within the gas turbine industry.”
Exelon permitting one of these projects at the U.S. EPA
Exelon Power, on behalf of Colorado Bend II Power LLC, had filed a Sept. 12 application at the U.S. Environmental Protection Agency for one of these gas-fired power projects. The application at EPA’s Region 6 office is for a greenhouse gas (GHG) prevention of significant deterioration (PSD) air permit to construct and operate two new combined-cycle units, referenced as the Colorado Bend II project, at the existing Colorado Bend Energy Center located in Wharton County.
To the extent practicable, the proposed project will make use of existing plant infrastructure, but will be an independent regulated source, the application said. The project will consist of two natural gas-fired combustion turbines (CTs), each exhausting to a heat recovery steam generator (HRSG), equipped with natural gas-fired duct burners (DBs), to produce steam to drive a shared steam turbine. The General Electric 7HA.02 model to be used has a maximum baseload output of about 328 MW. The total maximum output from the combined cycle project (i.e., two combined cycle units) with DB firing and the steam turbine will be approximately 1,157 MW.
Exelon Generation parent Exelon Corp. (NYSE: EXC) is the nation’s leading competitive energy provider, with 2013 revenues of approximately $24.9bn. Headquartered in Chicago, Exelon does business in 48 states, the District of Columbia and Canada. Exelon is one of the largest competitive U.S. power generators, with approximately 35,000 MW of owned capacity comprising one of the nation’s cleanest and lowest-cost power generation fleets.
Zachry Holdings has 90 years of experience delivering engineering, construction, maintenance, turnaround/outage and fabrication services to energy and industrial customers.