A discussion with ChatGPT about Geothermal Power generation and global warming

 Here is an exchange I had with ChatGPT,  for whatever it is worth.   Notice that I asked it a followup question, to which it also replied.   I wonder if its answers were correct.

You said:

Geothermal power moves heat from below ground to the surface. Compare this contribution to global warming with the amount produced by burning fossil fuels. per kilowatt-hour.

ChatGPT said:

ChatGPT

The contribution of geothermal power to global warming per kilowatt-hour (kWh) is significantly lower than that of burning fossil fuels. Here’s a comparison:

Geothermal Power:

• Mechanism: Geothermal power involves extracting heat from beneath the Earth's surface to generate electricity. This process does release some greenhouse gases, but the amounts are minimal.

• Emissions: On average, geothermal power plants emit around 50 grams of CO₂ equivalent per kWh of electricity generated. These emissions come from the release of trace amounts of carbon dioxide, methane, and other gases naturally present in geothermal reservoirs.

Fossil Fuels:

• Coal: Coal-fired power plants are among the highest emitters, producing about 820-1050 grams of CO₂ per kWh.

• Natural Gas: Natural gas plants are cleaner than coal, but still emit about 450-500 grams of CO₂ per kWh.

• Oil: Oil-fired power plants emit roughly 650-900 grams of CO₂ per kWh.

Comparison:

• Geothermal vs. Coal: Geothermal power produces about 16-21 times less CO₂ per kWh compared to coal.

• Geothermal vs. Natural Gas: Geothermal power produces about 9-10 times less CO₂ per kWh compared to natural gas.

• Geothermal vs. Oil: Geothermal power produces about 13-18 times less CO₂ per kWh compared to oil.

Conclusion:

Geothermal energy is a much cleaner alternative compared to fossil fuels in terms of greenhouse gas emissions per kilowatt-hour. While it does contribute some to global warming, the impact is negligible compared to the significant emissions from burning fossil fuels.

4o

You said:

Your answer to my previous question addresses how much CO2 equivalent is produced by geothermal power compared to fossil fuels, per kilowatt-hour, but does NOT address the heat from below ground that is moved above ground in the process. But this, too, warms the atmosphere, doesn't it?

ChatGPT said:

ChatGPT

You are correct that geothermal power involves moving heat from below the Earth's surface to above ground, and this heat can contribute to warming the atmosphere. However, the magnitude of this effect is generally very small compared to the contribution from burning fossil fuels.

Heat Contribution from Geothermal Power:

• Mechanism: In geothermal power generation, heat from the Earth's interior is brought to the surface to produce electricity. Some of this heat is converted into electricity, and the rest is dissipated into the environment.

• Magnitude of Heat Transfer: The amount of heat released into the atmosphere from geothermal power plants is relatively small. For context, a geothermal power plant might produce around 0.01-0.1 watts of thermal energy per square meter of Earth's surface. This is negligible when compared to the vast amount of heat naturally released by the Earth or the heat retained due to greenhouse gases.

Heat Contribution from Fossil Fuels:

• Mechanism: Fossil fuel combustion releases both thermal energy and CO₂, which traps additional heat in the atmosphere. The heat released during combustion is significant and directly warms the surrounding environment.

• Magnitude of Heat Transfer: Fossil fuels release a substantial amount of heat. For example, burning one kilogram of coal releases about 24 megajoules of energy, much of which is dissipated as heat, contributing to atmospheric warming.

Comparing Geothermal Heat Transfer to Fossil Fuel Combustion:

• Geothermal Heat: The heat transferred to the atmosphere from geothermal power is relatively small. It's typically in the range of 0.1% of the Earth's natural geothermal heat flux.

• Fossil Fuel Heat: The heat released by burning fossil fuels is far greater. In addition to the direct heat release, the CO₂ emitted leads to a long-term increase in global temperatures through the greenhouse effect.

Conclusion:

While geothermal power does move heat from below ground to the surface, its contribution to global warming from this heat transfer is minimal compared to the impact of burning fossil fuels. The primary concern with fossil fuels is not just the immediate heat release but the CO₂ emissions, which trap additional heat in the atmosphere and drive significant long-term warming. Geothermal energy remains a low-impact option in terms of both heat transfer and greenhouse gas emissions.

4o