Until very recently and for many decades the only power line that carried electric power across the Ontario-Quebec border, actually carried power across Eastern Ontario into New York State. That power line pre-dated the construction of the Moses-Saunders power dam near Massena, NY. Ontario's political leaders have only recently chosen to purchase up to 1200MW of electric power from Hydro Quebec and at very reasonable prices. Ontario has chosen to generate much more electric power at far higher prices at subsidized solar PV installations and has little power for export.
Quebec, Labrador (Newfoundland), Manitoba and British Columbia still have much untapped hydroelectric potential. One group in the Vancouver area proposes to install a north-south submarine power cable along the Pacific coast to carry electric power from British Columbia to California. While the cost of submarine power cables is usually higher that the overland route, there are times when there are advantages using the undersea route, such as along a known earthquake zone.
The distance of the proposed north-south submarine power cable is almost identical in distance across southern Hudson Bay that in recent years has been minus its usual ice cover due to changing weather patterns. The winter ice sheet over Hudson Bay usually builds up to a depth of 11-feet, in some 100-ft depth of water. There is also much hydroelectric development on the eastern and western sides of Hudson Bay and at almost the same latitude, with potential for mutual economic benefit by connecting the 2-systems in the future.
While Hydro Quebec operates their massive James Bay hydroelectric installations on the southeastern side of Hudson Bay, Manitoba Hydro has built and plans to build and operate additional hydroelectric installations on the Nelson River that flows into the southwestern area of Hudson Bay. The close proximity of power dams to both sides of Hudson Bay offers scope to install a UHV-DC submarine power cable directly across southern Hudson Bay, between the hydroelectric installations of Hydro Quebec and Manitoba Hydro. It has the potential to be cost-competitive and efficient by bypassing the lengthy overland route around the southern tip of James Bay.
Manitoba Hydro has already introduced UHV-DC power transmission to carry power from their hydroelectric power dams in their northeast region along the Nelson River. There are ongoing advances in raising the efficiency and capacity of that technology that promise to enhance prospects of increasing power transmission capacity across Manitoba. Such development would coincide with further development of the hydroelectric generation capacity of Northern Manitoba with possible power line connects extending west toward Prince Albert and Edmonton.
Government officials in Manitoba have indicated an interest in developing the hydroelectric potential that is available on the Nelson and Churchill Rivers and exporting much of that power to markets in the USA and in Western Canada. There have historically been very cordially and mutually cooperative political relations amongst the provinces of Western Canada as well as with the neighboring states in the USA. Such a political foundation enhances prospects to develop an east-west power grid across the 4-provinces of Western Canada.
Historically, there have been times when weather conditions reduced rainfall in some regions of Canada and either reduced or threatened to reduce hydroelectric output. There are multiple weather systems that affect wind and precipitation in various regions across Canada. It may be several years into the future before an east-west power grid appears and is able to carry available excess power from one region to be transmitted to another region. During times of excess competitively priced renewable power generation across all regions across Canada, there may be available markets in the USA willing to buy that power.
There is also the prospect accessing other power markets via UHV-DC submarine power cable. A potentially viable UHV-DC connection between Iceland and the European continent appears possible, with the prospect of extending such a power cable to Southern Greenland to access high-altitude wind energy outside of commercial flight paths. There may be scope to route submarine power cables through trenches that run perpendicular to the coast and into inlets around the periphery of the Labrador Basin between Greenland and Eastern Canada. During times of plentiful low-cost power generation across Eastern and Western Canada, a portion of that excess off-peak power could travel to peak-period markets across Western Europe.
The potential to earn revenue from generating power and selling to willing markets can often over ride political differences, as has been the case between Quebec and Newfoundland with related concerns between Quebec and New Brunswick. Except that the economic gain from generating and selling electric power to outside markets usually exceeds the political gain. It may be on such a foundation that an east-west power connection evolves to connect across and between the politically and culturally very diverse regions of Canada.