Toronto should contribute to power generation in the province, but Torontonians should be selective about the kind of generation they accept. While generation with health and environmental impacts is undesirable anywhere, it is of critical importance in a city like Toronto, which already pays heavily in air quality due to patterns generated outside its own borders. Carbon dioxide levels in Toronto are at 75% of established thresholds and frequent smog days in summer already have a heavy impact on health and productivity. The medical officer of health estimated that 1,700 Torontonians died in 1999 due to air pollution, with numbers rising each year.
While some of this pollution is the simple result of highly concentrated human activity and some is generated outside the city or even the province, a significant contribution is the daily flood of vehicles from outside the city, which permits many people to live in areas with cleaner air yet enjoy the jobs available in Toronto. We should be especially sensitive not to add to the burden that Toronto already pays. Our choice in generation should be of the lowest impact possible.
Low-impact power can help us meet our demand for electricity in two ways. Large projects can feed the grid in much the same way as conventional generators. Smaller projects operated by consumers can reduce demand. Small, dispersed energy projects should be encouraged because they help prevent massive system failure when a major component breaks down.
Recently, the Province has reached an agreement with sustainable energy groups to provide standard offer contracts to producers of wind and solar energy. This is an important step that could dramatically alter the way energy is produced and used in Ontario, contributing to a decline in demands on the existing grid in years to come.
Photovoltaics that transform solar energy into electricity have astonishing potential. With currently available methods of capture, covering 10% of the city (or about a quarter of the rooftops) in photovoltaics would generate all the electricity the city uses. Photovoltaics also conveniently work hardest on blistering summer days when demand on the grid reaches its peak.
The reason solar power has not been embraced more fully has been the prohibitive cost. With the introduction of standard offer contracts just announced by the Province, solar power will become much more economical as the Province pays 42 cents per kilowatt hour to all solar power producers. Photovoltaics will become even more economical in coming years as the payout to standard offer contracts increases to meet international standards. We can expect rapid increases in market penetration of solar power.
We should be encouraging investment in photovoltaics both on a large and small scale. Parking lots are inspired locations where instead of overheating cars, the sun can be put to use cooling our homes. Long-term goals of hundreds of megawatts are achievable.
Wind power in Toronto is very exciting because it is economical today. Construction costs are lower than those for nuclear reactors and operating costs are minuscule. In addition, winds tend to blow on winter evenings when demand is high. The two limitations of wind energy are site location and reliability. Our greatest potential for capturing strong winds is along the lake. A 60 MW wind farm is already being planned by Toronto Hydro in the lake near the Scarborough Bluffs and City Council has approved wind turbines for Ashbridges Bay. Additional potential exists on the land or water near the Toronto Islands and the Western Beaches. With sufficient political will, 100 MW of wind generation could be built within the few years it would take to build a gas-fired generator. Flow batteries or other storage methods could make wind power a reliable energy source. While wind farms can produce substantial contributions to the electrical mix, they are modularized — when a breakdown occurs in a single turbine, all the others on a wind farm continue to produce electricity, eliminating one drawback of other large projects.
Small rooftop wind turbines are being developed and will likely become economical in coming years, when they can help reduce electrical demand.
Electrical supply needs to meet demand. Our highest demand is on hot summer days. Solar power matches this demand because it is most productive just when it is most needed. A secondary peak occurs on cold windy nights, when wind turbines reach their highest output. Nonetheless, sun and wind energy require storage technology to level out differences in supply and demand. This is why the flow battery mentioned under “Demand Shifting” prepares us for a future where renewables play a larger role while helping level out supply and demand imbalances today.
An anaerobic digester could use Toronto's green bin waste to produce methane at a rate of 5,000,000 cubic metres per year for every 100,000 tons of waste. This methane could in turn be used in cogeneration. Toronto generates 600,000 tons of green bin waste annually. One third of this amount could be used in cogeneration at Ashbridges Bay, contributing 20 MW at peak to the grid. The remaining potential should be harnessed at other sites in the city.
Cogeneration merges production of useful heat with electrical production at a level of efficiency that simple generation cannot approach. A single-stage gas-fired electrical plant extracts 33% of the energy in fossil fuels as electricity and dumps the rest as waste heat into the lake. A combined-cycle generator as proposed by the Province turns some of the waste heat into more electricity, raising efficiency to 55%. Cogeneration can achieve efficiencies higher than 90% by using the heat directly. As a result, cogeneration is widely and correctly advocated.
As the Portlands were identified as a preferred location for power generation due to existing transmission lines, there have been repeated and ongoing proposals for cogeneration there. This approach is wrong-headed for two reasons. First, electricity is far more transportable than heat, so maximizing efficiency means siting cogeneration at the heat user rather than at the electrical lines. Secondly, when electricity overconsumption is the rationale for cogeneration, it creates a need for more heat consumption, introducing another problem. The Portlands has no heat recipient so cogeneration is not viable. Both the original Portlands proposal and the Toronto Hydro proposal have come to this conclusion.
Real cogeneration opportunities in the city should be explored. Every heat-intensive industry should be encouraged to produce electricity as a byproduct of its operations.
Conservation alone eliminates the need for any new power. Demand shifting alone eliminates the need for any new power. Cleaner power generation techniques can displace less desirable methods of generation by 100 MW in the short term, expanding to produce most of our power in the long term.
This document is part of a three-part Realistic Energy Plan for Toronto:
Conservation, Demand Shifting, and Cleaner Power.