The Michigan Department of Environmental Quality on Nov. 1 approved an air permit-to-install that would allow the Renaissance Power LLC affiliate of LS Power Development to convert its simple-cycle gas plant into a combined-cycle facility.
The Renaissance facility is located in Carson City, Montcalm County. Renaissance currently operates that this facility four simple cycle natural gas-fired Siemens 501 FD2 combustion turbine generators (CTG), a diesel-fired emergency generator, a diesel-fired firewater pump engine, and a natural gas-fired fuel heater, at this facility.
The proposed modification and conversion includes the addition of four heat recovery steam generators (HRSG) equipped with duct burners (DB) for supplemental firing and two steam turbine generators (STG), resulting in two power blocks, each in a “two-by-one” (2×1) configuration consisting of two CTG/HRSG and one STG. The CTG and duct burners were permitted to operate on natural gas only.
The project will require additional ancillary equipment to facilitate with startups and safe shutdowns of the facility including two 40 million Btu per hour (MMBtu/hr) natural gas-fired auxiliary boilers, two engine-driven 1,000 kW emergency diesel-fired generators each with a 2,000 gallon diesel storage tank. The existing ancillary equipment including the emergency generator, fuel heater, and firewater pump engine will remain and will not be physically modified. A mechanical draft cooling tower and water cooled condenser will be installed for the eastern power block. An air cooled condenser will be installed for the western power block, the agency noted.
Renaissance Power has offered to sell capacity from this uprated plant to Consumers Energy as an alternative to the new, gas-fired Thetford plant that Consumers Energy wants to build to fill a hole when it has to shut some of its coal units in 2016. Thetford is a combined-cycle plant initially planned for a 700-MW capacity when it comes online in 2017, with the option to double that later.
Consumers plans to suspend operations of seven small coal units, at the latest in April 2016, and on Sept. 9 applied at the Michigan Public Service Commission for securitization of costs related to those shutdowns. The affected coal units to be shut in 2016, and perhaps earlier, are:
- BC Cobb Units 4 (156 MW installed) and 5 (156 MW);
- JC Weadock Units 7 (145 MW) and 8 (145 MW): and
- JR Whiting Units 1 (101 MW), 2 (99 MW) and 3 (124 MW).
Renaissance offers to sell power from the uprated plant, or the plant itself
Consumers Energy is now before the Michigan Public Service Commission for approval of the Thetford project. Carolyne Murff Wass, employed by LS Power Development as Senior Vice President, Asset Management, said in Oct. 28 protest testimony filed at the commission that her company has offered to sell its plant to Consumers both last year and this year.
“The [PSC] should deny Consumers’ request for a certificate of necessity for the proposed Thetford Generating Station,” she wrote. “The Renaissance facility is a proven generating resource that has operated reliably since achieving commercial operation. The facility is located in MISO Zone 7 and is interconnected to the Michigan Electric Transmission Company‘s (‘METC’s’) transmission system. Further, the Renaissance facility would satisfy Consumers’ desire for more efficient, environmentally preferable gas-fired combustion turbine capacity to replace its older, less efficient, and less environmentally desirable coal units.”
She added: “Renaissance Power has offered to sell the capacity of the facility to Consumers at very favorable prices, and Renaissance Power has also offered to sell the facility itself to Consumers at a favorable price. Additionally, Renaissance Power has offered long-term [power purchase agreement] options wherein Renaissance Power has agreed to upgrade existing simple-cycle turbines to combined-cycle turbines with duct firing capabilities with a guaranteed heat rate and plant performance standard. In summary, Renaissance Power has offered Consumers options that fulfill the capacity need supplied by the proposed Thetford plant at a significant savings and less risk to Consumers and thus to Consumers’ customers.”
The Renaissance plant is a gas-fired facility with a net average annual capacity of about 716 MW. The current four units achieved commercial operation between 2002 and 2003.
Under one proposal to Consumers, Renaissance Power committed to converting three of its F-class simple-cycle peaking units to combined-cycle configuration thereby providing Consumers with 785 MW of base (summer) capacity and 895 MW total (summer) capacity with duct firing. Renaissance Power would assume the risk of construction and guarantee to Consumers a baseload heat rate of 6.95 MMBtu/MWh. Renaissance Power offered 20-, 25- and 30-year terms for a PPA starting June 1, 2017.
The Renaissance facility is interconnected to METC’s transmission system via a 345-kV transmission line into the Nelson substation. The plant is interconnected to DTE Gas Co. formerly known as Michigan Consolidated Gas Co., through a nine-mile lateral into the New Haven Compressor Station.