Implementation of an Integrated Solar Combined Cycle on an Existing Coal Fired Power Plant Available to Purchase

This paper presents the implementation of an integrated solar combined cycle (ISCC) on the existing 44 MW Cameo Power Generating Station, located in Palisade, Colorado. The plant was originally built in 1957 as a coal fired power plant, to serve the Grand Junction community. This plant has been chosen to demonstrate the viability of the ISCC because of its time line to decommissioning and the availability of additional power from nearby stations to fulfill the community’s needs. The solar system at Cameo utilizes 8 aluminum parabolic trough collectors arranged in 4 loops. Each of these collectors is approximately 150 meters long and 5.77 meters wide. The hot heat transfer fluid used in the solar field is sent to a solar feed water heater, located in between two of the existing feed water heaters, to supplement the thermal energy required by the steam cycle. At design conditions, the solar field will provide 4 MW of thermal energy to the power plant. The development of this ISCC has faced several design and construction challenges not common in traditional power plant and solar power plant design. When first constructed, the Cameo station had no provisions made regarding solar field location, heat transfer fluid piping runs, heat transfer fluid pumping station, thermal expansion vessels, the addition of solar thermal energy to the feed water system, and the integration of a solar field control system into the existing plant distributed control system. Also unaccounted for are the affects the integration of a solar feed water heater has on the thermodynamic efficiency of the steam cycle. This paper discusses these challenges, as well as their resolution, as seen during the engineering, procurement, construction, and commissioning phases of this project. The Cameo Power Generating Station is located in the DeBeque Canyon, 4 miles east of Palisade, Colorado along the Colorado River and Interstate 70. The solar feed water heating demonstration will be in operation for 1 to 2 years, at the discretion of Xcel Energy, to test and develop operating and maintenance methods for large scale application. After such time, both the plant and the solar field will be decommissioned. After decommissioning all applicable solar field equipment shall be refurbished and utilized at additional testing facilities.