Renaissance Power LLC is nearing an air permit from the Michigan Department of Environmental Quality that would allow it to uprate its simple-cycle gas plant into a combined-cycle facility.
MDEQ’s Air Quality Division is taking comment until Oct. 17 on a draft Permit to Install for this project. The MDEQ documents don’t give pre- and post-conversion MW ratings. The GenerationHub database shows that the four CTs at the plant each have a 170 MW nameplate rating (165 MW summer net), and that the plant is connected into the Consumers Energy transmission system. Renaissance Power is an affiliate of LS Power.
The Renaissance facility is an existing plant located in Carson City, Montcalm County, Mich. Renaissance currently operates 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 will be 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.
Notable is that Consumers Energy is currently developing the new, gas-fired Thetford plant 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.
Consumers Energy suspended operation of the currently gas-fired Cobb Units 1-3 in January 2009 due to safety concerns, and those units are still down. Original repair estimates exceeded $10m and the company suspended operation of the units with the intent of monitoring future market conditions. Since that time, market conditions have not warranted the investment needed to return these 65-year-old, small (183 MW combined operating capacity) and relatively less efficient units to service.
Cobb Units 4 and 5, Weadock Units 7 and 8, and Whiting Units 1-3 are currently operational. These coal units are subject to the U.S. Environmental Protection Agency’s Mercury and Air Toxics Standards (MATS), but have been granted a one-year extension for compliance by the MDEQ. The initial compliance date for the MATS rule is April 16, 2015, which has been extended for Cobb 4 and 5, Weadock 7 and 8, and Whiting 1-3 to April 15, 2016.
The affected coal units 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).