Natural Gas Oil

Great River Energy operates its peaking plants on the hottest and coldest days of the year, when demand for electricity is especially high. The plants use natural gas or fuel oil to generate electricity. Because peaking plants are more expensive to operate, we put them into service only when necessary to increase capacity. Our peaking plants include Cambridge Station, Lakefield Junction Station, Pleasant Valley Station and other combustion turbine stations.

Cambridge Station is a state-of-the-art combustion turbine plant, an approximately 150-megawatt natural gas-fired power generation facility in Cambridge Township, Isanti County. The plant was built on a site already owned by Great River Energy and adjacent to an existing, smaller generating unit.

The facility consists of a simple-cycle combustion turbine. The fuel for the facility will be natural gas, chosen for its low air emissions and ready availability from a nearby pipeline. The fuel supply will be provided on an interruptible basis, meaning the needs of other, higher priority uses, such as home heating, must be satisfied first.

Cambridge Station normally will be operated during times of peak electrical demand, which generally occur during periods of very high or very low temperatures. In addition, Great River Energy occasionally may be called upon to operate the facility to support voltage on the area’s transmission grid or for other grid support functions. Great River Energy anticipates Cambridge Station’s total operating time will average 500 to 1,000 hours a year. The majority will occur during summer periods of significant air conditioner use.

Great River Energy considers no phase of operation or administration as being of greater importance than the safety and well being of its employees. It is the policy of Great River Energy to provide the necessary resources to maintain safe and healthful working conditions and to follow operating practices that will safeguard all employees.

Lakefield Junction Station is a state-of-the-art combustion turbine plant. The plant is situated on 150 acres of land near Trimont, Minnesota, and is comprised of six units with a maximum capability of 102 megawatts each.

The peaking plant is capable of generating approximately 520 megawatts of electricity on a hot summer day and 550 megawatts on a cold winter day.

Lakefield Junction Station uses natural gas as its primary fuel; fuel oil as its backup fuel. Natural gas is transported to the plant via Northern Border Pipeline’s high-pressure, underground pipeline. Fuel oil arrives at the plant in tanker trucks.

Lakefield Junction Station is highly automated, and only six skilled operator / technicians are required to operate and maintain the plant. The plant came online in 2001.

The plant uses a simple-cycle combustion turbine process to convert fuel into electricity. A compressor furnishes large quantities of compressed air to a combustor which drives a 3-stage power turbine. The combustion process causes the turbine to rotate, driving both the compressor and a generator.

In late 2004, Lakefield Junction Station received International Organization for Standardization 14001 certification of its environmental management system. As a certified plant, Lakefield Junction Station has an environmental management system in place to continuously evaluate and improve environmental performance.

Pleasant Valley Station is Great River Energy’s newest natural-gas fired combustion turbine plant, with the first two units operational in 2001, and the third in 2002.

The power plant uses three large simple-cycle combustion turbines to produce approximately 420 megawatts of electricity on a hot summer day and more than 480 megawatts on a cold winter day.

The primary fuel for Pleasant Valley Station is natural gas, chosen for its low air emissions and ready availability. The backup fuel is fuel oil. Natural gas is provided to the plant via a Northern Natural Gas high-pressure underground pipeline. Tanker trucks transport the necessary fuel oil to the plant.

The station is located on 150 acres of land near Dexter, Minnesota, and is staffed by 5 skilled operators / technicians who operate and maintain the plant.

Pleasant Valley Station is a state-of-the-art combustion turbine plant. It combusts fuel through a high performance low emission DLN combustion process, which allows the plant to operate at high efficiencies with very low emissions.

In 2003, Pleasant Valley Station received International Organization for Standardization 14001 certification of its environmental management system. As a certified plant, Pleasant Valley Station has an environmental management system in place to continuously evaluate and improve environmental performance.

Great River Energy owns four combustion turbine plants located to the north and west of the Twin Cities area that run on fuel oil.

These units, like Pleasant Valley and Lakefield Junction Stations, are simple cycle combustion turbines. The combustion turbine stations are staffed with three skilled operator technicians who operate and maintain the four stations.

St. Bonifacius, located in St. Bonifacius, Minnesota, has a generation capability of 50 megawatts. The station is comprised of two combustion turbines connected to a single generator. St. Bonifacius has the ability to operate a number of hours in synchronous condenser mode. This allows the plant to carry operating reserves as well as voltage support for the electrical grid. The turbines at St. Bonfacius were originally developed as large aircraft engines which were modified to provide power generation;
Rock Lake, located in Pine City, Minnesota, has a generation capability of 22 megawatts;
Maple Lake, located in Maple Lake, Minnesota, has a generation capability of 22 megawatts; and
Cambridge Station Unit I, located in Cambridge, Minnesota, has a generation capability of 22 megawatts.