In 1999, 143.1 TWh of electricity was fed into the provincial power grid by Ontario-based generators. This includes 131.5 TWh of production from Ontario Power Generation (OPG) and 11.6 TWh from Independent Power Producers. In 1999, Ontario imported about 7.7 TWh of electricity and exported approximately 5.9 TWh, primarily to Michigan, yielding net imports of 1.8 Th. OPG's mix of generating assets currently in operation includes nuclear, coal, oil/gas-fueled and hydroelectric generation with a total capacity of 25,800 MW. In addition, OPG has capacity which is currently not operating. This includes nuclear capacities of 2,060 MW at Pickering and 3,076 at Bruce-A.
Due to recent reductions in nuclear power generation in the province, OPG's fossil fuel plants have increased power production to meet electricity demand. Independent Power Producers (IPPs) are generators that have contracts with the Ontario Electricity Financial Corporation (OEFC) to deliver defined amounts of capacity and energy. IPP generation includes hydroelectric as well as waste-fueled and natural gas-fueled thermal generation. IPP installations range in size from about 1MW to 165 MW with a total capacity of 1,766 MW.
In addition to OPG and IPPs, there are other electricity generators in the province that operate to supply electricity for their own internal use. These supplies are generally referred to as self-generation or internal-generation and are not made available to the provincial grid. The installed self-generation capacity in Ontario is approximately 1,500 MW. Self generation capacity includes about 986 MW in the industrial sector, of which only 517 MW is actually operated due to costs, 400 MW with other utilities, and 120 MW with municipal electric utilities and the commercial sector.
- Base load capacity operates to satisfy relatively constant demand;
- Peaking capacity operates intermittently to provide power during periods of maximum demand;
- Intermediate capacity operates fewer hours than base load capacity, but more than peaking capacity.
Fossil fuel electricity generation
Ontario Power Generation's fossil fuel generating stations are used to provide intermediate and peaking capacity to match fluctuations in electricity demand. While their short run marginal costs are high, these stations offer greater operational flexibility to take advantage of market opportunities compared with nuclear generating stations which are base load facilities that provide little or no operational flexibility. Fossil fuel generation has typically represented the smallest part of OPG's generation mix, operating primarily to satisfy peak demands. As a result of recent reductions in nuclear generation, OPG's fossil fuel generation has increased to support intermediate and base load needs.
Ontario Power Generation owns and operates six fossil fuel stations. A total of 23 generating units are currently in service with a combined power capacity of approximately 9,700 MW, representing approximately 38 per cent of its total in-service capacity. Coal-powered generating units at Nanticoke, Lambton, Lakeview, Thunder Bay and Atikokan account for approximately 7,600 MW of in-service capacity. Dual-fueled (oil/natural gas) generating units at Lennox account for approximately 2,100 MW of in-service capacity.
The location of each station is as follows:
- Lakeview is located in Mississauga, on the shore of Lake Ontario;
- Nanticoke is on the north shore of Lake Erie;
- Lambton is south of Sarnia on the St. Clair River;
- Lennox is near Kingston;
- Thunder Bay is on Lake Superior; and
- Atikokan is in northwestern Ontario between Lake Superior and the Manitoba border.
Ontario Power Generation's major fossil fuel plants were constructed during a period of high electricity demand when their output capacity was expected to be fully utilized. However, lower than expected growth in demand led to an oversupply of capacity and thus, OPG's coal plants were primarily used to meet demand during peak periods.
To meet demand in the face of declining nuclear generation with the shutdown of the Bruce A and Pickering A stations, fossil fuel generation increased between 1995 and 1999. To provide the majority of additional fossil fuel generation, the scrubber-equipped units at Lambton and the eight units at Nanticoke have operated essentially as base load units since 1995 and 1998, respectively. In 1998, OPG commenced an asset enhancement program at these stations, designed to improve mechanical reliability, safety and environmental performance.
Air Pollution and Fossil Fuel Generation
Air pollution from Ontario's power sector is generated almost exclusively in coal or oil/natural gas-fired stations. Domestically, OPG's six fossil fuel stations account for the following proportion of total domestic provincial emissions:
- 14.7 per cent of nitrogen oxides (NOx)
- 23.7 per cent of sulphur dioxide (SO2)
- 13.9 per cent of greenhouse gases (CO2 equivalents)
- 22.6 per cent of mercury (Hg)
As part of its efforts to reduce air emissions, OPG has already undertaken a number of initiatives including:
- increasing its use of low-sulphur coal;
- upgrading the low-NOx burners on all eight units at Nanticoke;
- converting all four units at Lennox to dual-fueling so that natural gas or oil can be used. Natural gas has no SO2 emissions and lower NOx emissions than oil;
- installing scrubbers in two units at Lambton to reduce flue gas SO2 content, completing combustion process modifications for two units and installing enhanced boiler controls in two units to reduce NOx emissions; and
- committing to the installation of four NOx removal technologies (SCRs) on two units at Lambton and two units at Nanticoke, and to the installation of low-NOx burners at the Lakeview station.
Ontario Power Generation has reduced the average NOx emission rate from its fossil fuel stations by 36 per cent since 1983 and 22 per cent since 1990 (as of 1999). Sulphur dioxide emission rates have been reduced by 68 per cent since 1983.
About The Lakeview Generating Station
Lakeview is located in Mississauga, Ontario on the shore of Lake Ontario. The oldest station in OPG's fossil fuel fleet, the plant's units entered into service during the period from 1962 to 1969. Lakeview's book retirement date is 2006. In practice, however, the station's lifespan can be extended indefinitely with overhauls and replacement of components. Current capacity is 1,138 MW from four coal-fired units (Units 1, 2, 5 and 6). Each unit consists of a coal-fired boiler, a steam turbine and a generator. Four generating units at Lakeview representing approximately 1,100 MW of power capacity were taken out of service in 1992 as surplus capacity. Significant expenditures would be required to reactivate and operate these units.
Lakeview provides two basic functions to support system reliability. It provides capacity to meet overall system loads and reactive support to maintain local voltages. The high demand for electricity in the Toronto area has meant that Lakeview is needed during peak periods to meet system demand. The Independent Electricity Market Operator (IMO) reports that, if some of the Darlington and Pickering units were not available during summer peak period, Lakeview would be necessary to maintain system reliability in the Greater Toronto Area.
Current plans are for Lakeview to continue its role to provide power during peak periods and as required for system reliability. Lakeview's in-service units were given extensive overhauls in the early 1990s. These units have an estimated remaining life of five to 10 years.
In 1999, Lakeview produced 3.2 terawatt-hours (TWh) of electricity, operating at 32 per cent of in-service capacity. The heat rate (a measure of efficiency) of Lakeview was 10,800 kilojoules (kJ) per kWh.
Pollution control technologies currently in place for Lakeview Units 1 and 2 include:
- boiler tuning and optimization using artificial intelligence to advise operators on how to minimize NOx formation;
- electrostatic precipitators controlling particulate emissions; and
- low-NOx burners currently scheduled for installation in 2001 at a cost of $4.4 million
Units 5 and 6 have the following:
- artificial intelligence system which directly controls the boiler to minimize NOx formation.
- Estimated reduction of 10 per cent at full load, and higher reductions at partial loads; and
- low-NOx burners installed and currently being commissioned. The expected emission rate for these low-NOx units is 1.3 kilograms of NOx per MWh (up to a 50 per cent reduction).
Lakeview is part of the Greater Toronto Area (GTA), which is home to about five million people. This heavily urbanized area requires substantial infrastructure to support business and industry, and a viable transportation network. All of this requires power Ñ and with the fossil-fueled generation of power comes air pollution. A comparison using recent GTA emissions inventories for NOx and SO2 emissions indicates Lakeview accounts for 26 per cent of the GTA's SO2 emissions and 8 per cent of NOx emissions.
The Lakeview station is a major source of local mercury emissions. Lakeview emitted 83 kg/yr in 1999 and is currently the second-largest emitter in the GTA. The largest is the KMS Peel incinerator in Brampton, Ontario at 140 kg/yr. The Peel incinerator is upgrading and soon its emissions will be reduced to 25 kg/yr, leaving Lakeview as the largest mercury polluter in the area.
Another facility, the Ashbridges Bay sewage sludge incinerator, emits about 68 kg/yr, but is slated to close in 2001. Operating as it presently does, by December 2001, Lakeview would clearly be the single largest mercury source in the GTA, emitting triple the amount of the next biggest source. The coal presently burned (characterized by 1,450 ppm chloride, 0.08 ppm mercury) produces a high proportion of ionic mercury - about 65 per cent of the total emitted. Ionic mercury tends to be deposited locally (i.e., within 48 km of its point of origin). ET