It has been exactly five years since Ontario opened up its wholesale and retail electricity markets to competition. That long, hot summer saw many power projects cancelled—the victims of uncertainties about profitability, despite rising provincial load. The results of the pullback were predictable: less reliability of supply and less-stable power costs. Regulators responded just as predictably: by quickly freezing rates for about half of Ontario’s electricity consumers.
Five years later, little new capacity has been installed in the province, which remains dominated by publicly owned Ontario Power Generation. As a result, only 25% of Ontario’s power consumers are reaping the putative cost benefits of competition. Making matters worse, demand growth has continued to outstrip supply, shrinking reserve margins. Over the past two years, Ontario’s Independent Electrical System Operator (IESO) has asked citizens 17 times to curb their electricity consumption. The most recent appeal was issued on August 2, as this article was being written.
According to the IESO, “By 2014, close to 13,000 MW of Ontario’s electricity requirements will need to be met with new supply or demand-side resources.” The good news on the supply side is that power projects totaling 7,000 MW of capacity (most of them gas-fired combined-cycle plants) are projected to enter service by 2011. The bad news is the provincial government’s stated goal to wean Ontario off of coal completely by 2014. If that plan is implemented, many of Ontario’s 6,500 MW of coal-fired plants will be shut down in phases, making maintenance of system reliability problematic.
Airport express
The Greater Toronto Airports Authority (GTAA) made power reliability and security a priority after the widespread northeast U.S. blackout of August 2003, which also affected parts of Ontario. GTAA had first considered building its own cogeneration plant back in 1998, but the project was deemed to lack a raison d’etre because Ontario’s regulated markets were keeping power prices low.
After deregulation in the summer of 2002, and especially after the blackout a year later, GTAA wasted no time reviving its plan to build a cogen plant. Executives envisioned the benefits of such a plant going beyond making the airport self-sufficient in energy. Any excess production could be sold on the open wholesale market, increasing the supply on the provincial grid and helping the IESO cope with rising demand. The twin rationales made economic sense, so this time the cogen project went forward and was completed. Named the GTAA Cogeneration Complex (Figure 1), it was the first of the aforementioned wave of gas-powered power projects to come on-line following Ontario’s adoption of its “off-coal transition plan.”
1. Quick response. The GTAA Cogeneration Complex broke ground 11 months after the northeast U.S. and Ontario blackout of August 2003 and was commissioned 19 months later. Courtesy: GTAA
In March 2004, a design, build, operate, and maintain contract for the facility was awarded to SNC-Lavalin Engineers & Constructors Inc. GTAA’s unique approach to the project was to hire a firm capable of doing more than just designing and building it. The contract called for an SNC-Lavalin subsidiary—SNC-Lavalin ProFac (www.snclavalinprofac.com)—to operate and maintain the cogeneration complex after construction. Now an established leader in operations and maintenance, SNC-Lavalin ProFac was founded in 1993 to offer facilities management services to companies in a wide range of industries.
Construction of the facility started in July 2004, and by February 2006 its 117-MW gas-fired combined-cycle was putting electrons on the Ontario grid. Steam from the cogen plant feeds the adjacent Central Utilities Plant (CUP) built to produce heated and chilled water. (More on it later.) As a result, Toronto Pearson International Airport now has the ability to get all of its electricity and its energy for heating and cooling from this off-site source. Surplus electricity is sold into the Ontario electricity market and routed through the local distribution system of Enersource Hydro Mississauga. The airport’s peak electrical demand is currently about 38 MW, but it is expected to grow to nearly 60 MW by 2015.
“Our first responsibility as managers and operators of the airport is to ensure the safety of our tenants and passengers,” said John Kaldeway, president and CEO of GTAA at the time of the plant’s opening. “[Being] able to guarantee a stable supply of power to Toronto Pearson was the driving force behind our decision to build the cogeneration plant.”
The GTAA Cogeneration Complex uses a common 2 x 1 combined-cycle configuration (Figure 2). Two 42-MW GE LM6000PD gas turbines exhaust into separate, dual-pressure, once-through heat-recovery steam generators (OTSGs) from Innovative Steam Technologies Inc. (IST, www.ostg.com). The outputs of the OTSGs are combined to feed a single 33-MW Demag Delaval ST4-CE300-L steam turbine from Siemens (www.powergeneration.siemens.com). The plant layout includes space for the future installation of selective catalytic reduction (SCR) systems for additional control of NOx emissions. SCR systems are not needed today because both gas turbines are equipped with dry low-NOx burners.
2. No drums, please. The 117-MW combined-cycle plant is configured 2 x 1, with two LM6000PD gas turbines from GE, two once-through heat-recovery steam generators from Innovative Steam Technologies, and one Demag Delaval steam turbine. Courtesy: GTAA
The CUP is outfitted with five 1,500-ton/hr electrically powered water chillers and two 2,000-ton/hr steam turbine�driven centrifugal chillers. If the steam supply from the cogen plant is curtailed, the CUP can make its own in four 65,760-lb/hr package boilers normally fueled by natural gas, with number two fuel oil as backup. The cogeneration complex also has a “black start” diesel generator that can be activated upon a total loss of power.
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