Interesting. I'm getting some very different numbers, but the same basic conclusion. Nevertheless, the given information seems to indicate geothermal, either can not, or simply does not supply the upper levels of power generation.
Currently there are:
54 Nuclear plants producing over 1,000 MegaWatts
13 of which are over 1,250 MegaWatts
12 Coal plants producing over 1,000 MegaWatts
9 of which are over 1,250 MegaWatts
1 Single NatGas plant producing over 1,000 MegaWatts
Geothermal only has 8 plants producing between 100 to 250 MegaWatts.
We have some assumptions to make. It could be that 100-250 range is the upper end for Geothermal plants. But most are smaller, under 50 MegaWatts.
There are larger plants producing more power using Wind, Solar, Oil, Hydro, and even a Biomass plant producing in the 500-750 MegaWatt range.
For example, The Geysers, is the largest Geothermal plant in the world, producing about 725 MegaWatts in California. But after you research it, it's actually a collection of 22 power plants using 350 wells, 19 of those plants, power that area. This means each individual plant is only producing about 38 MegaWatts.
The smallest Nuclear plant is 750 MegaWatts, and the largest over 1,250 MegaWatts.
We would need ~20-33 Geothermal plants to equal one Nuclear plant.
Another issue is cost. Many have claimed that Geothermal is cheaper. It is not. Geothermal is roughly the same cost as a nuclear power plant, per kilowatt of installed capacity. This is a major issue since Geothermal plants tend to drop in energy production as the area being tapped is used.
For example, back to The Geysers. The plant was expanded to an installed Capacity of 2,043 MegaWatts. This would roughly cost the same as two 1 GigaWatt nuclear reactors. However, The Geysers only nets ~725 MegaWatts.
In fact, The Geysers peaked out in 1986, and has been dropping ever since, with some plants currently operating at 25% capacity. That's a heck of a lot of money to end up with production less than half of what you paid for.
This actually dims my view from last time I explored this topic. However, again Geothermal has a good spot in energy generation, but it clearly (as things stand) does not have the ability to replace the big 4 energy sources... being Coal, Nuclear, Natgas and Hydro, which make up ~90% of our energy generation.
