http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf

Even with the prodigous detail in your comment, geothermal has got to be at the forefront of our energy portfolio and policy. The major cost factor in geothermal systems is drilling, not all of these resources require EGS and not all of them are “deep.” The point about cost competitiveness is absolutely spot on. The average operations and maintenance costs for geothermal plants is around $0.02/kwh - competitive with fossil. Transmission is identical. Fuel prices add additional cost to fossil plus the deleterious environmental effects.

The only difference remaining is capital cost to construct. The cost of a clean coal plant is now over $1B - or around $2M per MWe. The cost for geothermal on average is $2.5M per MWe. Over the long term due to fuel cost alone, geothermal must be more cost effective for the rate payer. While there are synergistic and desirable environmental benefits, the move to geothermal in a Manhattan Project type way is in the public’s best interest from a cost and climate perspective.

If you have access to the report PDF, read pages 16-17 of Chapter 1 for the context of Figure 1.7, which has the numbers you cite.

Somewhat confusingly, the figure has the total US consumption of energy in 2005, without qualification of what that means.

In fact, it is there to provide an apples-to-apples comparison. That number, which is available from the U.S. Energy Information Agency (see, e.g. http://www.eia.doe.gov/emeu/aer/txt/ptb0101.html), gives the total consumption of energy regardless of use - gasoline, heating with natural gas, electricity generation, etc.

EIA gives it as “99.89 quadrillion btu”, which the google unit conversion “99.89 quadrillion btu in exajoules” will tell you is closer to 105 EJ, rather than 100 EJ of the figure. But 100 is a nicer number to work with.

To go from heat to electricity, you need to specify flow rates, water temperatures, and some power plant details. These would be site specific.

Using a back-of-the-envelope approach outlined in Section 3.5 of the report, the 2 percent recoverable heat estimate would yield about 1,250,000 net MW of electricity. A still conservative 20 percent recoverable heat would yield about 10 times this.

These numbers give the amount of electricity that can be generated at any cost. This is a very, very important point to understand. Regardless of altruistic tendencies, cost drives pretty much everything in this show. For the EGS program to succeed, it absolutely must be cost-competitive with other kinds of electricity generation.

Regulated utility purchases of power must be deemed “prudent” in order for state regulators to allow them (ie, to allow utilities to pass the cost on to ratepayers), which generally means it’s a relatively low-cost item.

Along the West coast - in California, Oregon and Washington - utilities are bringing to the regulators plans for meeting future power needs that include a cost of greenhouse gas generation tacked onto fossil-fuel-based generation - typically $5 per ton of gas - in anticipation of future national regulation along these lines. This makes renewables (mostly wind, at the present) cost competitive with natural gas and coal-fired generation in the long run, and allows regulators to sign off on making renewables part of the generation mix .

It is in this spirit that the report forecasts 100,000 MW of net electrical generation from EGS by 2050 *** at cost-competitive prices ***. This is *not* the amount that is feasible, which as we saw above is much higher. It is the amount that regulators would have no problem deeming prudently priced. In fact, in only 11 years after getting funded, the report says EGS would reach “parity” with market prices (by exploiting the easier portions of the resource, I think), a point when 240 MW of capacity would have been built out (pages 43-44 of Chapter 9).

The report also touches on the concept of “energy parks,” where combined heat and power can be provided by the same resource, an additional value from developing the resource.