The energy potential in the Earth's tides is not really unlimited, nor even fully sustainable. However the creative energy in Canada's coasts may hold more potential than we ever imagined.
In fact, the continuous action of the tides has the effect of gradually draining the Earth's rotational force, to the extent that the Earth rotates more slowly by an infinitesimal amount each year. This effect will be slightly amplified by tidal energy projects, but it would only be noticeable after millions of years.
In Canada there are two conditions which dictate that we should pay extremely close attention to tidal power as a potential energy source.
1. In the Bay of Fundy, Canada has the world's strongest tides, and probably the world's best site for developing tidal energy.
2. Canada has by far the world's longest coastline, almost four times longer than that of the second place country.
Both of these geographic conditions warrant extensive study, in order to better understand the huge potentials implied. In both cases, it appears very obvious that our current understanding is inadequate, to say the least.
The flow of water in the Bay of Fundy has been estimated to exceed that of all the rivers in the world! Despite this, current technology and understanding have only produced a high end estimate of 1,000 MW (one GW) of total generation potential, among several Fundy sites, which is something like a few of the world's larger dams.
Fundy is being studied intensively, by both Nova Scotia and New Brunswick and with the input of Maine as well as many international players such as the U.K.'s Marine Current Turbines.
At present there is only some incidental power generation in experimental projects in Fundy.
There is one large, 200MW+ tidal power station in France, however this 1960s project uses a barrage style technique, where a dam is used to hold and then release the water brought in on the tides. The use of dams implies high capital cost and exaggerated problems with sediment and other environmental issues. Otherwise there are only a few operating tidal systems worldwide, many different approaches are being explored and it is quite likely that the optimal approach for developing Fundy with little environmental impact is yet to be understood.
The concept of exploiting Canada's vast coastlines for tidal power in a less focused way has hardly been scratched as far as I know. Never mind just the simple idea of just exploring our coasts. This has been done in a cursory fashion, of course, but never with an eye towards developing the artistic potential of the whole. The intrinsic cultural, sociological, esthetic and other considerations of Canada as a maritime nation are unmapped in any way.
The length and unknown potentials of Canada's shoreline (not just in terms of tidal power) are truly staggering. At 202,000 kilometers, our coastline is double the length of the Atlantic Ocean coastline and 70,000 km longer than even the Pacific Ocean! To be sure, much of that coastline is located in the far north. However with the advance of global warming, the length of our ice-free coast is growing in leaps and bounds.
This is a scenario that promises huge dividends for those who seek to unlock the creative potential of Canada's coast.