Minneapolis converted to buses in 1949–1954,[1] and in the early 1950s, Northern States Power Company (now Xcel Energy) acquired the building.[2] The University of Minnesota purchased the plant in 1976 for $1.[3]
Operation
The plant in its context along the Mississippi River.The plant at duskThe buildings of the U of M's Minneapolis campus
The facility heats 94 buildings (nearly all of the university's Minneapolis campus), provides electricity to cool 19 of those buildings, and provides steam to the University of Minnesota Medical Center, Minnesota State Board of Health and Cedar Riverside People's Center. Captured as the steam leaves the plant, pressure powers the plant and provides 20% of the university's electricity. The plant's steam is transported through an 18-mile (29km) network of tunnels to the campus buildings and would be enough to heat 55,000 homes.[3][4] Each student pays about $200 for energy and those in residence halls pay $375 a year for heat and air conditioning, water heating and dining services.[3]
The plant is university building #059.[5] The university's Energy Management department, part of Facilities Management, oversees the plant. Foster Wheeler Twin Cities was contracted with the U of M to operate it from 1992 to 2016, when Veolia North America took over.
Before pipes were reinsulated, employees needed breaks once an hour to work in the tunnels which reached 115°F (46°C). Insulation reduced the ambient temperature to 80°F (27°C), and the loss of energy from 10% to 4%, and over time resulted in a 25% campus-wide decrease in energy consumption.[4]
The university closed the Southeast plant to gut and rebuild the interior, and in 2000, reopened it and closed down its old coal-burning power plant.
Completed in 2005, exterior rehabilitation won a local historic preservation award, presented to the university and Miller Dunwiddie Architects, McGough Construction, Hess Roise Historical Consultants, Meyer Borgman Johnson, Michaud Cooley Erickson, INSPEC, Akiba Architects, and Kimley Horn.[7]
Boilers, fuel and emissions
Among the "cleanest burning power plants in the country," the high temperature fires almost completely consume its fuels—natural gas, fuel oil, coal, and wood waste. The plant has tested and been approved for oat hull biofuel, a renewable resource that would reduce each student's fees by about $21.[3][4]
Four boilers are operational. A fluidized bed boiler (CFB) is seven stories high and capable of burning fuel oil, coal, wood, oat hulls or natural gas. There are two natural gas boilers, and one pulverized coal boiler, that can also fire fuel oil. There is a spreader stoker coal boiler, also capable of burning fuel oil and possibly oat hulls that is decommissioned. During May and October, the periods of lowest demand, the CFB boiler is not in use.[6]
The CFB controls emissions of the acid gases sulfur dioxide, hydrogen chloride and hydrogen fluoride and particulate matter (PM) with limestone injection and a fabric filter. The pulverized coal and spreader stoker boilers are equipped with dry gas scrubbers (spray dryers). Two boilers have no control equipment but have flue gas recirculation to limit nitrogen oxide emission. The plant emits almost zero sulfur and mercury.[4]
The unloading terminal for rail cars and its conveyors are enclosed and equipped with baghouse filters. The outdoor coal bunker is shielded from the wind by concrete retaining walls. Storage silos for ash have fabric filters.[6]
Criticism
Environmental groups including the Save Our Riverfront Coalition and Friends of the Mississippi Inc. attempted and failed to move the plant off the river in 1996. Elected officials Phyllis Kahn and Larry Pogemiller, Arne Carlson who was governor of Minnesota, and Sharon Sayles Belton who was mayor of Minneapolis supported the move.[8] Concerned about potential emissions and noise from deliveries, some neighborhood associations and a condominium developer at the nearby Pillsbury "A" Mill criticized the plant's 2005 application to amend its permit to allow tests of alternative fuels.[3]
Biofuel
The Minnesota Pollution Control Agency approved use of biomass fuels, specifically oat hulls in 2006[9] but the three years necessary for testing and the approval process lost the source of the hulls. General Mills, makers of the oat cerealCheerios, had signed a contract by then with U.S. Steel for use in their facility on the Iron Range in northern Minnesota.[10]
↑ Minneapolis Heritage Preservation Commission and the Minneapolis Chapter of the American Institute of Architects (2007). "14th Annual Heritage Preservation Award Winners". City of Minneapolis. Retrieved 2007-04-08.
Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery to end users or its storage.
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.
Fluidized bed combustion (FBC) is a combustion technology used to burn solid fuels.
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turbine (CCGT) plant. The same principle is also used for marine propulsion, where it is called a combined gas and steam (COGAS) plant. Combining two or more thermodynamic cycles improves overall efficiency, which reduces fuel costs.
Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time.
A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning systems, which can both cool and warm interior spaces.
Xcel Energy Inc. is a U.S. regulated electric utility and natural gas delivery company based in Minneapolis, Minnesota, serving more than 3.7 million electric customers and 2.1 million natural gas customers across parts of eight states. It consists of four operating subsidiaries: Northern States Power-Minnesota, Northern States Power-Wisconsin, Public Service Company of Colorado, and Southwestern Public Service Co.
A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.
District heating is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or biomass, but heat-only boiler stations, geothermal heating, heat pumps and central solar heating are also used, as well as heat waste from factories and nuclear power electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH) is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants.
A thermal power station is a type of power station in which heat energy is converted to electrical energy. In a steam-generating cycle heat is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a steam turbine connected to an electrical generator. The low-pressure exhaust from the turbine enters a steam condenser where it is cooled to produce hot condensate which is recycled to the heating process to generate more high pressure steam. This is known as a Rankine cycle.
A heating plant, also called a physical plant, or steam plant, generates thermal energy in the form of steam for use in district heating applications. Unlike combined heat and power installations which produce thermal energy as a by-product of electricity generation, heating plants are dedicated to generating heat for use in various processes.
A pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal that is blown into the firebox.
Hal B. Wansley Power Plant is a power station located in northeastern Heard County, between Franklin and Carrollton, in the state of Georgia, United States. Its various units, powered by coal, oil, and natural gas, are operated by Southern Company, Georgia Power Company, Oglethorpe Power Corporation, Municipal Electric Authority and Dalton Utilities.
A coal-fired power station or coal power plant is a thermal power station which burns coal to generate electricity. Worldwide there are over 2,400 coal-fired power stations, totaling over 2,000 gigawatts capacity. They generate about a third of the world's electricity, but cause many illnesses and the most early deaths, mainly from air pollution.
JEA Northside Generating Station in Jacksonville, Florida is a major power plant, one of the three power plants owned and operated by JEA, Jacksonville's municipal utilities service. It produces electricity by burning coal and petroleum coke at Units 1 and 2, formerly the largest circulating fluidized-bed combustors, (CFBs), in the world. These combustors, completed in 2002 and rated at 297.5 megawatts each, produce enough electricity to light more than 250,000 households. In addition, Unit ST3 produces 505 megawatts of electricity by burning residual fuel oil and/or natural gas.
Kilroot power station is a coal and oil power station on the north shore of Belfast Lough at Kilroot near Carrickfergus in County Antrim, Northern Ireland. The station generates 560 megawatts (MW) of electricity from dual coal and oil fuelled generators, along with approximately 141 megawatts (MW) from four standby Gas Turbines and 10 MW of battery energy storage from the Kilroot Advancion Energy Storage Array.
The Wilton power station refers to a series of coal, oil, gas and biomass fired CHP power stations which provide electricity and heat for the Wilton International Complex, with excess electricity being sold to the National Grid. It is located on the Wilton site in Redcar and Cleveland, south of the town of Middlesbrough in North East England. The station has provided for the site since opening in 1952, when it was operated by ICI. The station is currently owned and operated by SembCorp Industries.
Repowering is the process of replacing older power stations with newer ones that either have a greater nameplate capacity or more efficiency which results in a net increase of power generated. Repowering can happen in several different ways. It can be as small as switching out and replacing a boiler, to as large as replacing the entire system to create a more powerful system entirely. There are many upsides to repowering.
Doosan Lentjes GmbH is a subsidiary of Doosan Heavy Industries & Construction. It is a company specialized in engineering, design and construction business that provides proprietary waste-to-energy and sewage sludge services and technologies, circulating fluidized bed (CFB) boiler technologies and air quality control systems (AQCS) to the thermal power generation, industrial and municipal sectors.
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