The Wisconsin Department of Natural Resources is taking comment until Jan. 21 on a draft air permit that would allow Wisconsin Power and Light (WP&L) to construct two new combined cycle natural gas-fired combustion turbines at the Riverside site.
These turbines will then feed the recovered heat as steam to a single turbine to generate additional electricity. In addition to the turbines, a boiler, natural gas heater, emergency fire pump and emergency generator and a cooling tower will also be included in the proposed project.
The Riverside plant is an existing facility that consists of two combined cycle turbines and other associated processes similar to those being installed under this proposed permit.
The proposed project, called the Riverside Energy Center Expansion (RECE), will consist of a two-on-one (2×1) natural gas combined cycle (NGCC) configuration that is comprised of two F-Class stationary combustion turbine generators (called CTG3 and CTG4), each with an associated heat recovery steam generator (HRSG) that will produce steam for a single, common steam turbine for additional power generation. No supplemental duct-firing is planned for the HRSGs, such that the combustion turbines will provide all of the heat for steam production.
The combined capacity of the three turbine generators will be nominally 660 MW, with ultimate generation capability dependent upon equipment manufacturer selection and detailed facility design. Pipeline quality natural gas will be the only fuel for the combustion turbines.
The primary emission units at the RECE will be two F-Class NGCC combustion turbines equipped with Dry Low Nitrogen Oxide (NOx) (DLN) combustors to control the emission of NOx. Each combustion turbine will have the capacity to produce a maximum estimated gross electrical output of nominally 220 MW at 60 °F. The steam turbine will have the capacity to produce a maximum estimated electrical output of nominally 220 MW. This gross power output is representative of a typical F-Class combined cycle configuration, but power output capability of combustion turbines can vary depending on specific manufacturer capabilities, system design and ambient air conditions.
Other emission units at the RECE that will support the operation of the NGCC facility will include:
- One natural gas-fired auxiliary boiler with a maximum rated heat input capacity of 99 million British thermal units per hour on a higher heating value basis (MMBtu/hr, HHV);
- One natural gas-fired fuel gas dewpoint heater, rated at approximately 14.3 MMBtu/hr, HHV;
- One diesel-fired emergency electrical generator rated at 2,000 kilowatts (kW) gross;
- One diesel-fired fire pump engine rated at approximately 315 horsepower (hp); and
- A ten cell evaporative/wet cooling tower, with a plume abatement design.
The auxiliary boiler will serve to help keep the HRSGs and other components of the facility warm, which will reduce warming and total start-up times for the combined cycle facility. The dewpoint heater will heat the incoming natural gas, as required, to ensure that there are no condensed hydrocarbons or other aerosols in the natural gas fuel supply stream to protect the integrity of the combustion turbines.
WP&L has also lately been pursuing approval of the RECE project at the Public Service Commission of Wisconsin.