CALGARY, Alberta, Jan 30 (Reuters) - Suncor Energy Inc (SU.TO: Quote, Profile, Research) said on Wednesday it will spend C$20.6 billion ($20.8 billion) on an expansion scheme that will make it the biggest producer in the oil sands of northern Alberta.

Suncor’s board of directors gave the go-ahead for the Voyageur project, a 200,000 barrel-a-day expansion of the company’s already massive oil sands operations near Fort McMurray, Alberta. Voyageur will boost output to 550,000 barrels a day when complete in 2012.

The project is the latest of more than C$100 billion worth of plans to tap the oil sands to feed demand from U.S. refiners for Canadian oil.

Production from the northern Alberta oil sands, the largest oil reserves outside of the Middle East, is expected to nearly triple to 3 million barrels a day by 2015.

The other interesting thing about the granite is that it has natural horizontal cracks, which can be widened by pumping water into them at great pressure. Because of the natural sideways force or shear stress in that part of Australia, when the flakes of granite settle after the pressure is reduced, the rock on either side of the crack doesn’t mate perfectly. As a result the permeability of the rock - its ability to transmit water - is increased a thousandfold.

The Innamincka geothermal resource extends over 1000 square kilometres. With one hole per square kilometre, and 40 holes per year, the resource would be fully developed in 25 years. The amount of energy it is estimated to be able to produce before the granite temperature is reduced to an uneconomic 150 degrees Celsius is equivalent to 50 billion barrels of oil, or one-fifth the oil reserves of Saudi Arabia, or 12 times the gas reserves of the North West Shelf.”

Not really renewable, then. An unusual form of nuclear power.

Still, emissions free and potentially very useful.

Does this mean that, after seventy years, the heat will run out? Is this actually a renewable resource, or just a stock of energy to be tapped?