EPCOR's proposed expansion of its Genesee coal fired generating station will be a world-class example of generation and emissions control technology. Scheduled for completion in 2005, the utility believes that the 400MW project can be implemented with acceptable environmental, technical, social, and economic results.
According to a recently released Public Disclosure document intended to inform government regulatory authorities, stakeholders and the general public about the utility's intention to expand the existing facility, EPCOR claims the third unit is needed to keep pace with the province's continued economic expansion.
Electricity Supply and Demand in Alberta
The need for a third unit is because of demand, and demand for electricity is being driven by Alberta's expanding economy - as it will be for the next several years. Historically, demand has grown at approximately three per cent annually. In the first six months of 2000, the Alberta Power Pool reported a five per cent increase over 1999 requirements. In the past three years, the provincial population has grown by 110,000 people to a total of three million. Increased industrial requirements for additional power are led by major expansions in oil sands mining and upgrading operations, in-situ bitumen projects, and petrochemical facilities. Business and residential consumption, particularly related to powering a growing number of highly sophisticated computers and appliances, places further stress on the existing power supply.
EPCOR expects that the future demand for electricity will continue to grow and that new supply must be added to meet that demand. Recently announced generation projects in the province are insufficient to meet large-scale demand. The majority are being built to provide on-site industrial generation, which means that only a limited amount of surplus power is available to the provincial market. Overall, growth will exceed the capabilities of currently proposed new generating capacity. This will substantially reduce the reserve power available and increase reliance on expensive imported energy, primarily from British Columbia where pricing is set by more lucrative markets in California. In 1999, Alberta paid $135.5 million for imported energy. In the first nine months of 2000, more than $183 million had been expended on energy imports from British Columbia and Saskatchewan. Increased natural gas prices have also contributed to higher electricity prices. Current Alberta Power Pool reports, detailing provincial supply and demand as well as future projections of electricity requirements, can be accessed on the Internet at www.powerpool.ab.ca.
With this in mind, coal-fired generation from the proposed Genesee Phase 3 project would provide a large-scale source of base load energy dedicated to the Alberta Interconnected Electric System. This would reduce dependence on high cost import power and exposure to the price volatility of natural gas.
Genesee Generating Station and Mine
The existing Genesee Generating Station consists of two coal-fired thermal electric generating units, ancillary support facilities and a cooling pond. The first unit began commercial operation in 1989.
The second came on stream in 1994, and is the newest coal-fired generation plant in Canada. Genesee functions with consistently high in-service ratings, and is one of the most efficient and reliable pulverized coal-fired power plants in Canada. The major operating design parameters for each unit include:
- generating capacity - 410 MW gross, 381 MW net;
- coal burning rate - 216 tonnes per hour;
- steam temperature - 540°C;
- steam pressure - 16.2 MPa;
- ash production - 39 tonnes per hour; and
- live coal storage - 40,000 tonnes (total).
Project Scope
The proposed additional Genesee unit consists of a 400 MW net base load electric generation facility. It would be constructed immediately adjacent to and east of the existing Genesee units, wholly within the existing site boundaries. Coal would be obtained from the adjacent Genesee surface mine. The existing cooling pond and coal-handling facilities are already sized to accommodate the capacity addition.
Genesee Phase 3 will use a single supercritical boiler and a high efficiency turbine. Approximately 25 per cent of the world's thermal electric power plants use this advanced technology. This will be the first unit of its kind in Canada.
In addition to a high efficiency boiler and turbine, the third unit will include:
- a dry flue gas desulphurization (FGD) unit for removing sulphur dioxide (SO 2 ) from flue gas;
- low nitrogen oxides (NO x ) burners;
- a high-efficiency dust-collection system, using fabric filters to reduce particulate and associated mercury emissions;
- a stack;
- condensing and cooling water equipment to minimize back pressure; and
- a generator transformer.
The major design parameters for Genesee Phase 3 include:
- generating capacity - 440 MW gross, 400 MW net;
- coal burning rate - 207 tonnes per hour;
- steam temperature - 540°C;
- reheat steam temperature - 565°C;
- steam pressure - 24.1 MPa; and
- ash production - 37 tonnes per hour.
Under the mine permit issued by the Alberta Energy and Utilities Board, there are sufficient mineable coal reserves in the Genesee development area to supply both the existing units and the proposed new unit for the next 40 years. Estimated coal reserves in the Genesee Coal Deposit, mineable from the surface, exceed 370 million tonnes. Currently, coal is mined at a rate of 3.4 to 3.6 million tonnes per year. Genesee Phase 3 would require approximately 1.6 million tonnes annually. The mine plan would be adjusted to reflect the increased rate of removal. The existing large-scale mining equipment and mobile fleet would be supplemented to handle the increased volumes of coal.
Supercritical Coal Combustion
The process of Supercritical Coal Combustion can be followed using the numerical references indicated in Figure 1: Coal to Electricity Process Diagram. Crushed coal is moved mechanically from the existing handling area to coal storage bunkers in the new plant (1-4). It is then pulverized and blown directly into the boiler where it is burned to produce heat (5). At supercritical pressures, water does not boil in the conventional sense. Instead, it gradually turns to steam with no sudden expansion. Water is passed through tubes in the boiler to absorb the heat from the burning coal. As the temperature of the water rises, the boiler produces steam at a rate of about 1.3 million kilograms per hour (kg/h). Steam is directed to the turbine and generation equipment (6-7).
During the combustion process, carbon and hydrogen in the coal are converted to carbon dioxide and water. Flue gas formed in the burning process travels through the boiler, where it cools from 1500°C to 140°C. After leaving the boiler, it enters a flue gas desulphurization (FGD) unit where sulphur dioxide is removed (10). The flue gas contains small non-combustible particles called fly ash. Solid particles of fly ash are filtered out of the cooled flue gas through a fabric filter before being released into the atmosphere (10). The filter removes more than 99.8 per cent of this particulate matter and reduces associated mercury emissions. Heavier ash falls to the bottom of the boiler where it is extracted as bottom ash.
Electrical Power Generation
The power generation process uses the steam produced in the boiler to drive a multistage turbine that generates electricity (6). The exhaust steam from the turbines is routed through a condenser, where it is cooled by fresh water from the cooling pond to become boiler water (8). Cooling water is pumped out of the pond and through the condenser and returns to the pond without coming into direct contact with the steam or boiler water (9). The recycled steam is returned as water to the boiler to repeat the cycle. The multistage turbine is connected to the electrical generator (7). The electricity produced by the generator is then increased to 240 kilovolts (kV) through a transformer at the plant (11). This high voltage electricity is transmitted into the Alberta Interconnected Electric System, and is distributed throughout the province. EPCOR has consulted with the Transmission Administrator regarding transmission capacity. The preliminary assessment indicates that, subject to minor modifications, the existing transmission infrastructure is capable of supporting the addition of Genesee Phase 3 generation into the Alberta grid.
Regulated Emissions
EPCOR's proposed additional third coal-fired electric generation at its existing Genesee Generating Station in Leduc will use supercritical pulverized coal combustion technology. Recognized as the best available commercial technology for this project, the third unit will increase efficiency by an estimated eight to 10 per cent, compared to the existing units.
One of the key considerations for the new plant design is emissions control. The third unit will be designed to comply with the applicable guidelines for NO x and SO 2 emissions, and particulates. It is recognized that air quality issues relating to particulate matter (PM 10 & 2.5 ) and mercury are under review in the Canada-wide Standards Process.
The Genesee Generating Station is one of the most efficient coal-fired power generation facilities in Canada. Technology selection will result in reduced emission rates for Genesee Phase 3 compared to the existing units. Low NO x burners reduce NO x by at least 20 per cent. The FGD unit will enable Genesee Phase 3 to achieve up to 60 per cent sulphur removal even if coal with unusually high sulphur content levels is burned. Particulate emissions will be controlled by installing a fabric filter. Fabric filter efficiencies exceeding 99.9 per cent are reported by plants burning coal with similar properties to that mined at Genesee. This would represent a 60 per cent improvement over the performance of existing units.
Greenhouse Gases
Genesee Phase 3 will have six per cent higher capacity than each of the other two units, and at the same time generate lower greenhouse gas emissions per unit of electrical output and on a tonnes-per-hour basis. Based on the amount of carbon dioxide emitted per unit of electrical output (kg/kWh), carbon dioxide output will be eight to 10 per cent lower at the addition than at the existing plant, and 18 per cent lower than at the average coal-fired power plant in Alberta.
At commercial start-up of Genesee Phase 3, EPCOR's goal is that net incremental GHG emissions will be equal to or lower than those from comparable combined-cycle, natural gas-fueled electrical generation. The utility is pursuing a diverse mix of programs such as landfill gas recovery, fly ash sales, water efficiency, customer conservation, wood pole recycling, tree planting, Green Power generation and emissions trading.
Socio-Economic Benefits
The expected capital cost of Genesee Phase 3 is estimated at approximately $500 million. The project will create employment opportunities during the environmental review, planning, design, site preparation, construction and operating stages.
EPCOR anticipates that as much as half of the total cost could accrue to Alberta businesses, many of which represent national and international firms, for a wide variety of goods and services. In-house expertise will be supplemented by engineering and other technical resources. Service and construction contracts will be awarded on a competitive basis to Alberta firms that have the required capacity and skills. Specialist requirements will be sourced nationally and internationally. Most of the large-scale equipment, including turbines, the supercritical boiler, and mining equipment are expected to be purchased from U.S. or overseas manufacturers, as none currently exist in Canada.
The project will create approximately 750 person years of direct and indirect employment during the 30-month period of site preparation and construction. Genesee Phase 3 will create up to 60 new full-time staff positions in the plant, in addition to the 130 current operating positions. About 65 new positions will be created at the coal mine resulting in a total estimated mine staff of 140. The construction and operation of Genesee Phase 3 will provide significant direct and indirect economic benefits to the local and regional economies. The project will strengthen the property and industrial tax base of Leduc County, as well as increase taxes or royalties for all levels of government.
From a provincial perspective, the project will provide a large, reliable source of electricity and allow the province to make use of its abundant reserves of low-sulphur thermal coal.
About EPCOR
EPCOR Utilities Inc. is a holding company with wholly-owned subsidiaries that provide electricity, water and natural gas services to customers in Alberta and technology services to markets across Canada.
EPCOR currently has assets of $2.8 billion and annual revenues of $1 billion. It employs about 2,000 people in its various business units.
EPCOR Generation Inc. currently operates three generating stations which supply a total of 1,615 MW into the power grid-approximately 20 per cent of Alberta's electricity:
- Genesee Generating Station, coal-fired - 762 MW;
- Clover Bar Generating Station, natural gas-and landfill gas-fired - 632 MW; and
- Rossdale Generating Station, natural gas-fired - 221 MW.
EPCOR Power Development Corporation (EPDC) is responsible for the non-regulated generating portion of EPCOR's business. It is the proponent of the Genesee Phase 3 project, and the 170 MW natural gas re-powering of the Rossdale Generating Station in Edmonton, Alberta. EPDC is currently a partner in the 416 MW natural gas-fired cogeneration plant near Joffre, Alberta; the 249 MW natural gas-fired plant at Frederickson, Washington; the 12.75 MW Taylor Coolee Hydroelectric plant near Magrath, Alberta; and the 7 MW small hydro project at Brown Lake, British Columbia. ET