The Alberta Utilities Commission on Dec. 15 approved an application by Northstone Power Corp. to add a new unit at its power plant that is larger than originally approved.
Northstone constructed and operates the Northstone Elmworth Generation Station, which is located in the Elmworth area southwest of Grande Prairie. The existing power plant consists of four 3-MW natural gas units, although the approval permitted the construction and operation of five 3-MW natural gas units.
Northstone recently asked to to install a 9.3-MW natural gas unit in place of the fifth 3-MW natural gas unit. With the addition of the proposed unit, the power plant would have a total capacity of 21.3 MW. Northstone also applied to connect the altered power plant to the ATCO Electric Elmworth Substation. Northstone indicated that the proposed unit is manufactured by Wartsila and is designated as Wartsila 20V34SG. The other four units at the site are Cooper-Bessemer LSV-16 reciprocating engine/generator sets.
In its December 2013 application, Northstone explained that it applied for the amendment, in part, because the proposed unit is more efficient than the fifth 3-MW unit. The proposed unit would have an efficiency of 44%. The fifth 3-MW unit, like the existing units, would have an efficiency of 32%.
Noted the Dec. 15 approval about plant operations: “Northstone testified that the northwest part of the Alberta Interconnected Electric System had experienced weaknesses and the existing power plant was located in a part of Alberta that had a need for generation, resulting in the AESO issuing Transmission Must Run (TMR) directives. TMR is another type of ancillary service and is ‘generation required to be online and operating to ensure reliability in specific areas of Alberta where there is insufficient transmission capacity to support local demand and guarantee system reliability.’ Northstone confirmed it operated in the nighttime during the early months of 2014 to respond to a TMR directive. At the hearing, Northstone indicated that effective May 1, 2014; its operating policy was to only operate during the daytime hours. Northstone went on to further state that the TMR directives issued to it were voluntary and it had the choice of whether to comply with the directive.”