Heat is stored and released throughout the earth's crust, often in dramatic forms such as deep rift zones or volcanic activity. In a more benign transfer, however, we can access high-temperature zones that allow heat exchange near the surface, including through heat "mining" at great depth where fracturing and pressurization can deliver a continuous flow of steam heat at the surface.
The heat available increases at depth, not universally, but with a gradient and geographic reach that makes some form of geothermal energy accessible virtually everywhere. Various forms of technology have been developed to utilize earth energy, from residential heat pumps to sophisticated hydrogeologic turbine sites.
Now, thanks to two recent reports, we have new incentive to add geothermal resources to our toolbox of energy technologies.
In 2006, a report from the Massachussetts Institute of Technology outlined the broad availability of heat resources at depth throughout most of North America using enhanced geothermal systems or EGS.
Basically, this form of energy release anticipates drilling wells into hot, dry formations at depths of at lease five kilometres, fracturing and flooding the underlying rock formations, and recirculating hot water and steam at the surface to generate baseload electricity. The potential is impressive, with projected energy supplies sufficient to replace aging coal and nuclear facilities at competitive cost levels in as little as 15 years if we start investing today.
A report by the Institute for Sustainable Energy, Environment and Economy (ISEEE), released in July, that explores some of the deep EGS potential in Alberta, concluded that competitive heat resources are accessible even in a province far from hot zones in contrast to areas of natural heat generation such as Meager Creek area in British Columbia.
The potential for deep geothermal energy is not confined to electricity. Steam for co-processing of foods, drying biomass, pre-processing of oilsands reserves and natural gas fuel substitution are just a partial list of the palette of energy supplements available.
None of this is free, of course. We must develop new drilling techniques for accessing heat at great depth; we must improve our ability to consistently fracture and flood rock at these depths, not to mention improving the efficiency of our generation technologies at the surface. The resource that is closest to the surface is not uniformly distributed, so some geographic areas will be easier to develop than others.
In the meantime, energy needs, especially in electricity generation, continue to grow. Simultaneously, existing power plants face retirement, either through age and inefficiency or through non-compliance with new environmental standards.
Thus, we must not only build new capacity, but replace a significant amount of existing capacity. This is a challenge that requires long-lived investment that will provide attractive investment opportunities as well as strengthen and diversify the grid.
In light of this, exploring the range of heat resources makes good business sense. Moreover, it makes good policy for federal and provincial government leaders. Geothermal energy is clean, with no net carbon contribution, and it may provide sufficient carbon credits in the future to offset much of our residual fossil energy production.
The challenge is to develop a greater understanding of the potential of this energy form, and begin to exploit it systematically and economically.
Recent success in France and Australia in being able to access and stimulate the reservoir gives investors and ultimately grid operators confidence that this is a reliable and cost-effective form of energy.
Future experience with deep recirculation of heat resources may well prove to be a key to reducing dependence on natural gas for heating oilsands and other unconventional oil resources, especially as they become more valuable in the market. The missing link is the incentive to invest in what must still be considered risky technology.
We have experience in this area both in Canada and the U.S., where we support promising technology through tax incentives or actual research and demonstration projects.
So what should we do? We must build the geothermal resource into our energy planning and infrastructure development. To do that, we must begin a comprehensive mapping program to identify the extent and quality of this resource throughout Canada. Further, we must collaborate with researchers in the U.S. and in Europe to identify potential heat zones for demonstration projects.
Finally, we can use this emerging technology as the poster-child for a national policy that integrates smart, sustainable energy technologies with our existing fleet of hydroelectric and fossil generation in ways that respond to power supply and quality challenges through the end of the century.
Planners and policy-makers tend to embrace the next new thing. This one turns out to be right beneath where you are standing.