By Rick Miell, Electrician, City of Lamar, Colo.
The Arkansas River Power Authority’s (ARPA) Lamar Repowering Project is moving forward. The new coal handling equipment is almost complete, as is the interconnection between the boiler and the generation units. ForeRunner Corp. is providing the engineering and design for the project and a combination of ARPA/Lamar Utilities Board staff and Samuel Engineering staff is providing the construction management. The new plant is scheduled to be online in June 2008, with the Lamar Utility Board as operator.
The new generator will be capable of producing 18 MW of electricity, while the old generator will continue to have a capacity of 25 MW, for a total generation of 43 MW when generating at 100 percent capacity.
 GE steam turbine prior to being placed on metal skids for installation in the Lamar Utilities power house, on the right. |
ARPA undertook this repowering project in 2003 to fulfill baseload power requirements of its member municipalities. ARPA elected to use coal when the cost of natural gas rose to a prohibitive level. Coal will be delivered to the site via a railroad spur to a rail unloading site, where the 12,000 tons of coal (approximately one trainload) will be unloaded onto a conveyer under the tracks. The coal will then be conveyed to two storage domes, each of which will hold 6,000 tons of coal.
The coal will be drawn out of the domes through an underground conveyer system and then will be brought into a crusher. The crushed coal, along with a mixture of crushed limestone, will be conveyed through overhead conveyers to the main structure, which will feed the mixture into the new coal-fired circulating fluidized bed boiler. The boiler will receive its water from either a soft water well on-site or use city water that is first taken through a large reverse osmosis system.
The new 18 MW turbine will be cooled by an air-cooled condenser. The existing 25 MW turbine will be cooled by water wells supplied from 20 wells owned by the Lamar Utilites Board.
All cooling water from the system will be sent to a local irrigation canal for use by downstream farmers. “Water will be somewhat warmer than normal, but not by much and we have been told that the farmers like the warmer water in the early spring,” Lamar Light & Power Superintendent Rick Rigel said.
The exhaust from the coal combustion will be filtered through a series of filters that remove over 95 percent of the particulates, and will be sent up the 227-foot exhaust stack. The resulting ash then will be moved to the ash silo for disposal.
Fire detection is a big concern of this new system. Infrared detectors, along with various other types of detectors, are being installed along every portion of the coal handling system, from the rail unloading building to the dust collection system. All systems will be monitored and controlled from the operator’s control room in the existing plant. This control room will not only control the operation of the new and existing generators, but will monitor and control the transmission and distribution operations of the entire Lamar electric system, monitor and control the existing wind farm south of town and wind generation from the nearby Springfield site.
Workers to operate the new plant and associated equipment are starting to become an issue, one that will need to be addressed soon. The need for workers with a good work ethic is utmost in the view of Rigel. “If we can hire workers with a good work ethic, we will give them the training to do their job,” he said. Rigel said there will be between 20 and 30 new jobs once the plant is up and running, with some needed for the material handling portion. But the majority of new workers will be in the plant itself. Wages are also a concern of the Lamar Utilities Board, since the closest plant construction locations (Pueblo, Colo. and Holcomb, Kan.) are offering higher wages for construction workers as well as for plant and infrastructure employees such as linemen and electricians.
ARPA member municipalities include Holly, Colo., La Junta, Colo., Lamar, Colo., Las Animas, Colo., Raton, N.M., Springfield, Colo., and Trinidad Colo. ARPA member’s power purchases equal 337,000 MWh hours, with a total peak demand of around 80,000 kW annually.