|
||||||||||||
There are alternative sources of renewable energy other than hydroelectric power that may also be developed in this region. Wind farms are being developed in several regions across Eastern Canada near hydroelectric installations in the windswept regions of Quebec as well as Labrador. Canada has another significant form of renewable energy that may be developed from energy in the oceans the nation's eastern, western and northern coastal regions. The Triton Group (1) of Vancouver recently completed the first phase of a comprehensive research study on the power potential from the ocean energy off Canada's coasts.
Northern Tidal Power:
The Triton study indicates that ocean tidal currents in Hudson Strait (Nunavut Region) and in the neighbouring Ungava Bay (Quebec)(5) have a combined power potential of over 30,000-megawatts. Most of the tidal power in Eastern Nunavut occurs in seven channels; four channels are located at the western end of Hudson Strait (21,600-Mw) and three smaller channels (7700-Mw) at its eastern end. Tidal power is also available at five river inlets along the Ungava Bay coast of Northeastern Quebec (3800-Mw). The total combined power potential in Hudson Strait and Ungava Bay exceeds 33,000-Mw. Over a period of 12-hours, incoming tidal surges in this region can last between 5 to 7-hours while receding tides can last between 2 to 5-hours. The table below (1) provides a summary of the power potential of Hudson Strait and Ungava Bay.
Increasing Northern Tidal Power:
The table above shows the capacity and power densities for the potential tidal power generation sites in Hudson Strait. The channels at the western end of Hudson Strait have a high power potential and a low power density. The power density may be increased by constructing short ramps of rocks and boulders on the sea floor and across the channels. Marine turbines would subsequently be located above the ramps. As the incoming tides rises, the ocean currents would accelerate to higher velocity as they flow over the raised ramps. Power varies to the cube of the velocity and a higher velocity would increase the overall power generation potential in the "ramped" channels.
The raised ramp could reduce total channel cross-section to 65% its former value and raise channel flow speed over the ramp by over 25%. Water flowing through a deep channel at 8-feet per second toward the ramp could have its surface height drop 7-inches when it flows above the raised ramp. The velocity would then be increased from 8-feet per second to 10-feet per second. The total power potential above the ramp would be increased by 26.9%, [(10**3)/(8**3) x 0.65 = 1.269]. If the surface height of the water above the ramp dropped by 1-foot, the water would flow above the ramp at 11.34-feet per second and the power potential would increase by 85%.
Short ramps on the floor of the main channels in Hudson can reduce channel depth to less than 400-feet at the western channels and to less than 350-feet at Gray Strait. The velocity of the currents that flow over the proposed ramps in the channels could be raised along with the potential power (from 29,000-Mw to between 34,000-Mw and over 43,000-Mw). The total combined power from the channels in Hudson Strait and the inlets in Ungava Bay could approach 50,000-Mw. Further research will need to be undertaken in regard to installing ramps on the channel floor to increase the power density in the main "power" channels in Hudson Strait.
The proposal to install ramps made from boulders and rocks on the ocean floor at some of the channels may inevitably require an environment assessment to determine the possible impact on the local ecology. The spaces between the rocks and boulders could serve as habitat for certain species of ocean life. It is possible that the economic benefits to the ecology in the ocean and on land may exceed any detrimental impact in the local area. The environmental issues involved in introducing tidal power generation in Hudson Strait and Ungava Bay may be solvable. The technical issues involved in northern tidal power generation will include energy storage and power transmission.
Energy Mega-Storage:
Tidal power generation has a propensity to occur during times when demand for power is low. Tidal mega-power conversion would therefore require mega-storage capacity. The hydroelectric dams in Quebec (James Bay installations) and in Labrador (Churchill-Falls installation) have the capacity for such storage and can be modified to operate in hydraulic storage mode during certain hours. The equipment needed to pump water to higher elevations at these hydroelectric installations is commercially available and could be installed at a future time. The development of tidal mega-power generation in Hudson Strait would depend on the development of sufficient hydraulic storage capacity, the availability of which would also benefit the development of wind mega-power (2) projects that could be built in the severely windswept regions of Northern Quebec and Northern Labrador.
The storage technology used by natural gas industry could also be adapted to store energy produced by tidal power. Salt domes that have been flushed of rock salt may measure up to one-mile in diameter and up to six-miles in vertical height. It is possible that subterranean salt domes may exist in the bedrock of Northeastern Canada and salt that could be flushed from them could go directly into ocean water. This action would partially offset the concern that global warming would melt the polar ice caps and decrease the salinity of the world’s oceans. The emptied salt domes could be used as storage for compressed air. Salt domes and salt jugs (small salt domes) that protrude above maritime sea level and into the Everett Mountains and Torngat Mountains could be partially flushed of salt and used for hydraulic storage using ocean water.
Hydrogen Production:
A market demand for hydrogen is likely to develop in the Northeastern United States and in Western Europe over the next several years. There is also a potential hydrogen market that may emerge in China and in Japan. Hydrogen has been carried across the North Atlantic (from Quebec to France) inside spherical containers aboard ships. Global warming is causing thinner ice in the Canadian Arctic and could eventually allow ships to travel between the North Pacific and North Atlantic through a shipping route that lies immediately to the north of Canada.
Hydrogen that is generated from tidal power at points along Hudson Strait could be exported to markets in Western Europe, Asia and in North America. It may also be possible to transport hydrogen by undersea pipeline from Hudson Strait under Hudson Bay and to markets in Central Canada and Central USA. That pipeline could be built in a similar way as the undersea pipeline that carries natural gas from Norway to the United Kingdom. The power generated from tidal currents in Hudson Strait could also be transmitted to markets at southerly locations.
Power Transmission:
The second technical issue involved in northern tidal mega-power generation would be long-distance power transmission. The distance from the western channels in Hudson Strait to Hydro Quebec's James Bay installations is considerable (over 500-miles). Power from Gray Strait and from Ungava Bay may be connected over a similar distance into Hydro Quebec's power lines. There may likely be high costs involved in building conventional power transmission lines across the hard rock of the Canadian Shield. Those lines will likely pass through the windswept (3) regions of Northern Quebec where wind mega-power (2) projects may be developed. The combination of tidal mega-power development along with wind mega-power development could justify the cost of building power transmission lines into the northern regions in Quebec.
A possible alternative form of efficient, long-distance power transmission may be possible. Tesla microwave mega-power transmission is a controversial technology that can offer high efficiency and lower cost by using fewer towers (1-tower per several miles vs. several towers per mile). Cost benefits may also result from the lower maintenance costs involved in long-distance transmission of electrical power. Further research may need to be undertaken into Tesla technology in order for it to be accepted as a viable alternative. Other possible alternatives may include long-distance submerged power lines that could carry power from northern power generation sites to markets located in more southerly regions.
Northern Ice and Shipping:
The pack ice in Hudson Bay and in Foxe Basin has a submerged thickness of 8-feet. Giant icebergs of over 100-ft submerged depth are typically found in Baffin Bay and Davis Strait that is to the west of Greenland and are brought south by the Labrador Current. The tidal currents that enter Hudson Strait can carry giant icebergs westward into the strait. Ships that tow icebergs usually place steel cables around them before attempting to move them to different locations. Cables that are secured to land (Southeastern Baffin Island to Resolution Island and to the Button Islands) may be suspended below the keep depth of ships by floating buoys across Gabriel Strait (Baffin Island to Resolution Island) and the eastern entrance to Hudson Strait. The cables could theoretically prevent the majority of errant icebergs from entering Hudson Strait.
The turbines that will generate power in the channels of Hudson Strait will need to be protected from pack ice. One possibility would be to suspend the upper level of the turbines just below the depth of the pack ice in Hudson Bay. Structurally re-inforced pontoons that are designed to incorporate icebreaker technology may suspend batteries of vertical axis marine turbines. The pontoons may be restrained by submerged cables that are secured to land on either side of the channels and as well as to the channel floors. "Icebreaker" pontoons would be able to withstand the pressure that winter pack ice would exert on their structurally re-inforced sides while the turbines would continue to rotate below the depth of the pack ice and drive electrical generation gear housed inside the pontoons. Submerged power cables would carry the power to the shore.
The ships and boats that travel through Hudson Strait typically have relatively shallower keels that those found on large oil tankers or container ships. Buoys that hold the submerged cables across Gabriel Strait and the eastern entrance to Hudson Strait may include lighting be registered on the GPS system. They may be spaced sufficiently far enough apart so as to allow passage to the ships and boats that typically sail through Hudson Strait. A special shipping channel may be established at the western entrance to Hudson Strait, perhaps between Salisbury Island and Nottingham Island so as to allow ships passage to/from Hudson Bay and Foxe Basin.
Power Markets:
There are massive (growing) power markets in the northeastern United States that may be willing to purchase electric power from tidal installations in northeastern Canada. New York State has an environmental law that forbids the importation of new electric power that may be generated at new mega-hydroelectric dams. Power from tidal installations seems to be acceptable. American investors and venture capitalists have actually offered to cover part of the cost of a tidal power installation at the Bay of Fundy (~ 2500-Mw)(1)(4). They may be willing to consider investing in tidal mega-power generation in Northeastern Canada depending on whether Canadian officials are willing to entertain such a concept.
Political Implications:
Canada is a resource-rich nation where energy invariably ends up becoming a political issue. A waterway with a power potential of some 40,000-Mw of renewable energy at stake is a political issue. The main channels where tidal power could be generated in Hudson Strait are in Nunavut territory. The ocean water that flows in the channels is under Canadian federal jurisdiction. Jurisdictional issues will first need to be resolved before any turbines can be installed anywhere in Hudson Strait.
The second issue pertains to gaining access to the immense energy storage capacity that exists in the hydroelectric dams of Quebec. Ocean water could still be pumped uphill from Hudson Bay into hydraulic storage in some of the hydroelectric dams in Western Quebec during periods of severe summer drought. A tidal mega-power would indirectly provide Quebec with a secure source of revenue and fulfill a political objective of promoting Canadian national unity.
A northern tidal mega-power project in which the federal government would “participate” would achieve such an end (7). The mega-power project would serve numerous environmental objectives by offering the American Northeast access to electric power from a competitively priced, clean and renewable source of energy. It would also provide ample power to sustain a fleet of electrically powered municipal transit vehicles and a large fleet of electrically rechargeable automobiles in Eastern Canada and the American Northeast in the future.
References:
(1) http://www.triton.ca Canadian Ocean Energy Atlas (Phase 1) by Michael Tarbotton and Max Larson, Triton Consultants, Vancouver.
(2) http://www.energypulse.net/centers/article/article_display.cfm?a_id=1263
(3) http://www.windatlas.ca
(4) http://www.energypulse.net/centers/article/article_display.cfm?a_id=1193
(5) Map at: http://www.waterlevels.gc.ca/english/Canada.shtml
(6) Map at: http://en.wikipedia.org/wiki/Image: CapeChidleyAreaMap.png
(7) http://www.energypulse.net/centers/article/article_display.cfm?a_id=1044
