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Power Pricing and Energy Storage along the St Lawrence River System
- Posted on January 12, 2010
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There is interest on both sides of the international border in increasing both wind power generation as well as nuclear power generation in the regions that lie within close proximity to the waterway. There is significant potential for offshore and even on shore wind energy generation along the shores of the Great Lakes. One group has announced plans for an offshore wind farm of 4400MW peak output for Lake Erie while other proposals involve the shores of the other Great Lakes.
The nature of wind power generation is often unpredictable and makes access to energy storage capacity essential. Having access to such storage capacity has the potential to enhance the long-term reliability and the economics of thermal power generation, especially nuclear power. In a market-driven pricing structure, power prices would be higher during peak demand periods that during the overnight off-peak periods.
Constant Power Prices:
However, Ontario observes a non-market driven pricing structure for electric power that disregards changes in market demand during the day, instead opting to maintain a cost price for power irrespective of actual market demand. Lower power prices during the overnight off-peak period can justify the cost of developing and operating large-scale energy storage systems. The absence of price fluctuations for electric power during the course of a 24-hour day essentially nullifies the economic case for energy storage.
Operating thermal power stations at constant temperature, constant steam (or gas) pressure and constant output throughout a 24-hour day minimizes the onset of thermal stresses. Such operation can extend useful service life and can greatly reduce long-term operating cost while increasing the return on investment. Thermal power stations are more likely to incur thermal stresses and resulting stress cracks due to having continually fluctuate system temperatures, pressure levels and power output throughout the day and every day to suit market demand.
Eventually, the build up of thermally induced stress cracks requires that part or all of a thermal power station be shut down to allow expensive repairs to critical components to prevail. Costs can typically run into the millions of dollars. The savings that would accrue from operating multiple thermal power stations at constant output, could justify part of the cost of developing some form of large-scale energy storage system. However, non-market driven costs may also apply to nuclear power generation in some jurisdictions that have a propensity for nuclear cost over-runs.
Idle Wind Turbines:
At night and especially during the winter months, powerful winds frequently and reliably blow over the Great Lakes. The constant 24-hour (partially subsidized) power price of $0.15 kW/hr in Ontario actually justifies the economic case of tilting the blades of wind turbines to prevent the rotation of the drive shaft and subsequent power generation. Depending on the regulator and the power transmission companies, there may be potential to export wind-generated electric power from Ontario and across to the USA at an agreeable price and to a location where some form of energy storage capacity may be available.
Until Ontario allows the power pricing structure to evolve into a system determined by market demand instead of by government decree, there may be an economic case to sell excess off-peak power from Ontario at attractive prices into USA-based storage systems. Such storage systems could be located along the waterway that connects Lake Superior to the Great Lakes and be covered by and subject to some form of unusual international agreement. Such agreements could be implemented at Niagara Falls where NYPA could then theoretically generate greater output than Ontario Power Generation between Lake Erie and Lake Ontario.
Essentially, New York Power Authority would operate pumped hydraulic energy storage while Ontario Power Authority would not, despite being "just across the border" and practically at the same longitude and latitude. The agreement could allow NYPA to install pumping turbines as well as additional tunnels and runners at Niagara Falls to generate additional power during peak periods, using the volume of water they had pumped to higher elevation during the off-peak period.
Powerful winds regularly blow over the eastern shore of Lake Ontario toward an abundance of high elevation sites in the Adirondack region of Northern New York State, where there are hundreds of possible locations to install wind turbines. During windy off-peak periods, the wind turbines could supply hundreds of mega-watts of power to a storage system. One option for NYPA in that region would be to develop an underground pumped hydraulic system immediately downstream of the Moses-Saunders power dam near Massena NY.
Geological research from Clarkson University dispelled an earlier fear of a possible geological fault under the St Lawrence River near the Moses-Saunders power dam. During 1944, an earthquake devastated a portion of the built-up region near the location of that dam, with an epicenter believed to have been under the Adirondack Mountains if not as far south as the Catskill Mountains. Clarkson researchers later discovered that most of the severely damaged buildings had been constructed above LEDA clay that liquefies when subject to vibration such as earthquake tremors.
In the remote event that Ontario actually allows for a market-driven pricing system to eventually evolve for electric power, both NYPA and Ontario Power Generation could jointly install pumping turbines into the Moses-Saunders power dam to pump water between Lake St Francis and Lake St Lawrence. Such an option would depend on the installation of similar pumping turbines at the power dam at Beauharnois along the St Lawrence River near Montreal. Evolving initiatives that are occurring along the lower St Lawrence River in Quebec could provide for such opportunities.
Initiatives in Quebec:
There are proposals to modify the Lower St Lawrence River between Montreal and the Gulf of St Lawrence to allow the new generation Panamax 2 vessels access to a modified terminal at the Port of Montreal. These ships sail with 50% greater length and 50% greater beam (width) that earlier generation vessels that sailed the river. The keel depth or draft is being increased from between 25-feet and 32-feet to between 45-feet and 60-feet draft for the newer vessels. One proposal for the partial unloading of the large vessels in the Gulf of St Lawrence and allow them to carry reduced loadings to Montreal.
There are numerous ways to allow deeper draft vessels to sail the lower St Lawrence River while conserving water and providing new opportunities in power generation as well as energy storage. Besides dredging or deep dredging the riverbed, it would also be possible to install control dams with optional power generation (and hydraulic pumping equipment) between the river shore and several islands in the river to reduce overall volume flow rate. While unpopular, it would be possible to install navigation locks along the lower St Lawrence River to provide deep-draft, wide-beam ships with passage to Montreal.
The aforementioned initiatives that are possible along the lower St Lawrence River can help conserve water in the Great Lakes and provide new opportunities to generate electric power and store energy hydraulically between Lake Ontario and the Gulf of St Lawrence. It would become possible to pump water to higher elevation from the confluence of the Ottawa River and St Lawrence River into Lake St Francis, with subsequent potential to pump water to higher elevation from Lake St Francis into Lake St Lawrence and the upper St Lawrence River.
Hydro Quebec owns a nuclear power station of 645MW output while Quebec has installed over 2000MW of peak wind generation capacity. Installing pumping turbines in the power dams between Montreal and Lake Ontario would make more efficient use of wind energy in Northern New York State to the east of Lake Ontario, Western Quebec north of Montreal and Eastern Ontario. Quebec has much on-shore and offshore wind energy potential along the eastern coasts of James Bay as well as Hudson Bay and within close proximity to Hydro Quebec's James Bay hydroelectric installations.
There is potential to develop pumped underground installations immediately downriver of the power dams at Massena NY and the southwest of Montreal. Each such installation would divert less than 10% of the outflow from the power dam to generate 1000MW during peak periods. A curved breakwater near a possible Massena facility could divert a greater proportion of the downstream water flowing from the power dam into the ship navigation channel downstream of Lake St Lawrence, thereby assuring sufficient water depth for the ships.
An underground pumped hydraulic storage battery located within close proximity to Montreal would have the potential to provide back-up emergency service. During the winter of early 1998, Montreal was literally without power for several days during a severe ice storm and has through its history endured prolonged power outages. There is hard impervious bedrock at the power dam near Montreal that is favorable for the development large excavated underground chambers located up to 2000-ft below river surface and for the purpose of pumped hydraulic storage.
- Ontario's non-market driven pricing structure for electric power undermines the economic case for large-scale energy storage. This pricing structure could see wind turbines remain idle during the off-peak overnight periods in regions where powerful winds blow. One possible alternative could see excess off-peak electric power from Ontario wind farms being sold at market prices to customers and markets outside Ontario.
- Ontario and New York have the potential to jointly to develop their pumped hydraulic potential at Niagara Falls and at Massena-Cornwall, after both sides observing a pricing structure for electric power that reflects actual market demand during peak and off-peak periods.
- Initiatives along the lower St Lawrence River between Montreal and the Gulf of St Lawrence could provide opportunity to develop pumped storage at 2-power dams between Montreal and Lake Ontario.
- Hydro Quebec's reservoirs in the James Bay region have been known to fill to capacity during the springtime melt, leaving little or no reserve capacity. Excess overnight springtime power generation from the James Bay region could, in the distant future, be transferred into storage at other locations in Quebec.
- Ontario's present pricing structure for electric power may justify the case to install pumped underground storage technology immediately downstream of the power dams at Massena NY and to the southwest of Montreal.